FLOW OF FLUIDS MURRAY WEINTRAUB Combustion Section, Branch of Bituminous Coal, Division o f Solid Fuels, Technology, U. S. Bureau of Mines, Pittsburgh 7 3, Per.
IIE science and technology of fluid dynamics cover so great a range of subject matter that only the most general classifications can be used t o organize a review of current developments. The subdivisions for the present review are: singlephase flow, f l o ~through fixed porous media, multiphase flon-, and the mechanics of pump and pipe operation and construction.
T
SINGLE-PHASE FLOW
Several valuable texts have appeared on various broad aspects of fluid mechanics. The book by Daugherty and Ingersoll ( 8 A ) very competently covers all basic phases of the subject. Chapters on fluid properties, hydrostatics, and fluid dynamics are followed by discussions of vortexes, cavitation, compressibility, and unsteady flows as well as instrumentation and rotating machinery. A recent German text ( H A ) covers similar material but places greater emphasis on topics of interest t o the aeronautical designer. Two good books of more restricted subject coverage are those by Shapiro (66A) on supersonic and high subsonic flom and by Rcrry ( S A ) on fans, flow, and ventilating engineering. Closed Conduits. Publications dealing with pipeline flow can generally be classified as studies of skin friction and other wall effects, investigations into momentum and bulk fluid dynamics, and evaluation and compilation of basic empirical data. While this latter group may not add appreciably to a deeper understanding of fluid mechanics, they frequently constitute new tools of great value to the design engineer. Among these tools is an National Advisory Committee for Aeronautics (NACA) collation ( S A ) of formulas and thermodynamic functions of perfect and imperfect gases in compressible flow. Frictional losses for flow of gases at low absolute pressure may be computed more accurately as the result of tkvo recent publications (6A, S1A). Also worth noting by those who may have occasion to deal with the materials in question are a new determination of friction factors for gas pipes (6A) and friction coefficients for white fuming nitric acid (48A). Keyes and Keenan ( 1 9 A ) have pointed out that a serious gap exists in the data available on the properties of steam in the extreme regions that just now are being opened up by new boiler design. They suggest that these data are of such importance that an international organization should be established to carry out the necessary research. In dealing with flow of non-Newtonian fluids, even the application of empirical data is beset with problems. Martin (S7A) discusses thc information required for crude oil-pipeline design, organization of calculations, and comparison between design calculations and observed values. The pour point has frequently been used as an index of pumpability of residual fuel oil. Gill and Russell ( I S A ) show that this is not a satisfactory criterion, as it does not indicate the lower limit of pumpability nor demonstrate any anomalous behavior that may exist. A rational design for such a system requires a knowledge of yield stress and of the functional relationship betn-een rate of shear and shear stress function. The authors discuss the type of equipment necessary
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foi obtaining proper design data. Other papers on the flon of non-Nev tonian liquids include one by RIerrill ( S S A ) on the floa of some Buna-N solutions under high-velocity gradients, and one by Narayanamurti and Handa (44A) on an investigation of the, rhrology of adhesives. The capacity of pressure-relief lines is determined by the attainment of sonic velocity in the expanded gas. Roberts and Cornell (,50A) calculated the proper pipe dimensions for this condition by three different assumptions of gas compressibility. They show that the assumption that the gas under consideration is ideal would give the most conservative result, although all three methods investigated show little difference in the desigii diameter computed for any specified length. Another practical application of a gas compressibility relationship was made by Sukkar and Cornell (61A), who developed tables and curves of integrals that permit direct calculation of the bottom hole pressuies in deep gas wells. Analyzing the mixing of two streams of gas is a problem that occurs in several common engineering situations. Efflux of stack gases into the atmosphere is a phenomenon of great complexity becausc of difference in physical properties of the two gas streams, because of temperature and velocity gradients, and because of the effect of terrain. Btrom and Halitsky (60A) and Sherlock and Leshrr (67A) have investigated similitude requirements for the convei sion of wind-tunnel studies t o practical application. On the basis of ~ i n d - t u n n etests l Ibing ( M A )has deduced quantitative design parameters for the control of chimney domwash. Somewhat more amenable to mathematical and empirical investigation is the miving of strong jets nith atmospheric air. Kocstel ( S d A ) computed velocity and temperature distribution of an air jet leaving a unit heater; Helander, E’en, and Knee (18.4) made an experimental investigation of such a device and studied the effect of variously shaped nozzles. Another study was made by Acharaya (1-4) who investigated the design of a cylindrical injector-i.e., an air jet which induces another air stream in a coaxial enrlosing cylinder. I n a flowing stream, energy is dissipated in the body of the stream because of viscous and turbulent shear, and a t the fluidsolid interface because of skin friction. Investigators have attacked each of these fields separately and have made measurements of over-all energy requirements for various situations. This last approach is typified by the work of Tao and Donovan (&SA), who report their theoretical and experimental stud& of flow through annuli of small clearance. They have analyzed the effect of eccentricity and of motion of the walls. In studies of momentum interchange in a stream of fluid, thc point a t which laminar f l o ~is replaccd by turbulent flow is obviously of great importance. Prengle and Rothfus (47A)have studied this transition by dye-filament injection terhniques. They have previously reported that departure from laminar flow occurs a t a Reynolds number as low as 900. After an investigation to determine how much of this effect is caused by the presence of their dye-injectors, they now report that their injectors do not create a disturbance; the critical Reynolds number is,
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FLOW OF FLUIDS however, a function of the injector diameter. Measurements M itli injectors of several diameters and evtrapolation tso zero diameter raise their estimate of the critical Reynolds number to 1225. Dye-filament waves m r e broken into true eddies a t a hulk Reynolds number of 2130 zk 35. In a study of fully developed turbulent flow in pipes, Sandborn (65A)has found that changes in momentum in the radial direction are as large or larger than the equivalent terms in the longitudinal direction. A number of basic theoretical developments in fluid kinetics have required a knowledge of the velocity distribution within the flowing stream. Rothfus and Monrad (6,9A) present a new correlation of turbulent velocities for tubes and parallel plates. Their parameters are found to be independent of the Reynolds number in the turbulent core. Ferrell, Richardson, and Beatty ( I ?,4) have used a novel dye displacement technique to establish that in laminar flow the predicted parabolic distribution persists to within 0.002 inch of the tube wall, R-hich constitutes the limits of their measurement. The important influences of skin friction and boundary layer upon the total energy requirements in a fluid system have been fiequently pointed out. Nikuradse and others have shown that frictional coefficients for very rough surfaces reach a constant value a t a relatively low Reynolds number. Hoerncr (31A) has noted, however, that certain tests on ship bottoms have contradicted these earlier findings. Hoerner believes that this discrepancy is due to the effect of the concentration of roughness a 3 distinct from the effect of relative roughness. Frictional losses in short lengths of pipe are dependent upon changes in the boundary layer flow. Ross ( 6 1 A ) presents an analytical solution for the development of the boundary layer which permits the calculation of the pressure drop. The ratio of this quantity to the corresponding value for fully developed f l o ~is found to be independent of Reynolds number. Rothfus and others ( 5 S A ) found by direct measurement that entrance effects on annular sections depend upon the Reynolds numher. Dorrance and Dore (9.4 ) have analyzed mathematically the effect of mass transfer on turbulent boundary-layer friction. Eckert, Diaguila, and Donoughe ( 1 1 A ) have investigated this problem experimentally. They have found that an appreciable decrease in the friction factor can be achieved by injecting a few per cent of air into the main channel through the porous valls that constitute the conduit. A novel method of making the boundary-layer transition visible is reported by Main-Smith (S6A). Open Channels. Flow through opcn channels is chiefly the problem of the civil engineer, thus, we find among the papers dealing with this subject one on the computation of channels of complex section vrith m a ~ i m a efficiency l (10-4 ) in \T-hich the word “maximal” implies construction of a rhannel nith minimum e\cavation costs. Other publications of interest to the hydraulic engineer include a compiehensive book on steady flotv in canals and rivers (69A)and a description of a new laboratory for experimental research in high-speed, open-channel flo~v (64A). A paper by Bleines ( 4 A i on flokv in a channel consisting of a deep
MURRAY WEINTRAUB, a native New Yorker, received his B.Ch.E. from the Cooper Union Institute of Technology and M.S. from the University of Pittsburgh. H e is engaged in process development and research in fluid-solid flow at the U. S. Bureau of Mines, Central Experiment Station, Pittsburgh, Pa. Weintraub is a registered professional engineer and a member of the American Chemical Society and AIChE.
March 1956
“main portion with shallow ledge may be of use in computations of flood control. Flow Through Equipment. The patterns of flow through process equipment and systems are frequently so involved that they can be resolved only through the process of establishing a parallel problem in another physical system that is governed by analogous laws and for which independent and dependent variables can be measured more easily than in the parent system. Isakoff (84A) shows the analogy between pressure and flow fluctuations and electrical oscillations and demonstrates the solution of unsteady fluid-flow problems by direct electrical aualogs. He gives examples of many types of problems and their solutions, such as those involving surges, frequency response, and pressure transmission in measurement and control. Hahnemann and Ehret (15A) explain how the principles of analogy permit use of an electrolytic tank for solutions in two- and three-dimensional fluid-flow problems. I n some cases the laws of fluid flow lead to simplified representations of other systems. Thus, Juhasa (2YA) uses a hydraulic analogy to determine heat-transfer coefficients for multipass, cross-flow heat exchangers and is able to include in his analogy an allowance for variation of the specific heat of fluid with temperature. Laitone ( S S A ) describes the use of hydraulic analogs for studying compressible gas flows. Another technique in studying complicated flona consists of introducing smoke or dust tracing filaments into the fluid stream. This method is, of course, not applicable where the equipment under study is not transparent. Herzig and TIansen (19A) make effective use of a novel technique to study vortexes and radial flon- in bladed rotating machinery. In one set of experiments, these investigators painted the blades with a white lead paint and introduced hydrogen sulfide gas into the flowing air stream; the resultant discolorations in the paint gave an accurate representation of gas f l o a~t the surface of the blade. These investigators found that vortexes generated a t blade surfaces accumulate in critical spots and cause flow disturbances and changes in the effective angle of attack on adjacent blades. Simple barriere that can direct these vortexes to less critical spots can cause an appreciable reduction in energy losses. Among all process equipment involving complex flow patterns, combustion systems probably represent the ones of greatest economic value and the ones for Tvhich the fluid-dynamic processes involved are the least understood. Thring (67A) suggests that some of the major unkno\Yns in combustion systems could be resolved by a frontal attack consisting of model tests on the lines of the Ijmuiden trials for open-hearth furnaces. The large dimensions of modern petroleum distillation columns make control of the liquid distribution of major importance. May and Frank (38A) traced cyclic disturbances in pressures and flow in several large towers to hydraulic gradient generated by gas drag along the surface of the liquid. When the cause of the difficulty was demonstrated, the solution was relatively simple; the submergence of the bubble slots was adjusted to provide approximately uniform hydranlic gradient. I n this adjustment, adequate consideration had to be given to preventing overcompensation a t different flows. Munk ( @ A ) presents a summary of the available correlations of fluid mcchanics that govern distillation tray design and of graphical means for rapid calculations. A problem that occurs in distillation-column design, in certain types of heat exchangers, and in other rhemical process apparatus, is that involvccl in liquid moving as a film dorm the side of a tube. By dissolving radioactive material in a liquid, Jackson (%$) found that liquids with viscosities less than that of water exhihited an average film thickness equal t o that expected for viscous flow, despite the formation of waves a t low flow rates. More viscous liquids showed films thinner than predicted; the amount of deviation is a function of viscosity. Problems of pressure drop in heat-exchange equipment arise chiefly because of the limitless forms that this equipment can
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UNIT OPERATIONS REVIEW
Sonic and mechanical agitation can affect operability of a fluidized bed..
amume. Grmsmann and Hildesheimer ( 4 4 ) describe a heat exchanger in which loose-fitting orifice plates surrounding the heat-exchanger tubes create accelerated gas flow and high turbulence, thereby increasing heat-transfer rates. Frictional data for porcupine-like tubes are presented by Hobson and Weber (2OA). Other equipment problems for which fluid mechanics studies have provided solutions include those of perforated-plate absorption columns (68A), continuous flow reactors in which variable residence time creates problems ( H A ) , and hydrostatically lubricated bearings ( 7 A). Metering and Control. About one third of the year's developments in metering deal with the application of the orifice and related types of meter to situations not covercd by the AG-4ASMK standards. The other papers describe developments in the use of other types of flou--met,ers. Murdock, Faltz, and Gregory (43A)discuss the deviation that results when the straightening length preccding an orifice plate is less than the minimum rccommended by the AGA-ASME. Experimentally detcrmined curves show the amount by d i i c h the indicated flow is in error. Thrasher and Binder (66A) explore the effect of edge thickness on small-orifice meters. If the edge thickness is greater than 1/40 of the pipe diameter, the discharge coefficient increases with edge thickness. Thibessard (66A) discusses the effect of elastic deformation of flow-mcasureinent orifices and Hutton (%?A) analyzes the effect of wall roughness on Venturi-meter coefficients. A fairly common source of error in fluid meteiing is oscillation produced either by fluid pulsations or by vibrations evternal t o the meter. IIaughton and Gorton (16A)have measured errors as great as 83% with an external axial vibration of 5 g. a t 150 cycles per second. The effects of transverse vibrations \?-ere not as important as axial ones. Zarek ( 7 2 A ) states that imdcr pulsating flow a U-tube manometer indicates the mean differential pressure across the orifice, but that the coefficient of discharge, as defined for steadystate conditions, is no longer applicabIe. Oppenheim and Chilton (46A)made a comprehensive survey of the literature of pulsating-flow measurement. They made a critical analysis of various approaches to all phases of the subject from primary elements through translation of the signal to ultimate recording. Yew primary metering elements and modification of old elements are constantly being described, each with advantagcs claimed in specific metering situations. A device that provides a high measurable pressure drop with a very 10x5 permanent head loss is the Dall flow tube ( @ A ) . This element, dvllich combines the characteristics of both orifice and FTenturi,secures i t s advantage a t the cost of several disadvantages, such as sensitivity t o solids, and narrowness of range of constant coefficient. The theory of another device for securing low permanent head loss, the rounded-entrance flov meter, is lxell worked out by Rivas and Shapiro (49A). Jorissen (26A)discusses discharge measurements at lorn Reynolds numbers and the development of a new primary elemcnt with constant discharge coefficients at low flows. Another meter with adjustable sensitivity for low rates of flow is described by Wenger (71A). Other metering elements have also come under the scrutiny of various investigators. MacMillan (56.4) measured viscous effects on Pitot tubes a t Reynolds numbers from about 15 to 1000. Swirles (62A) studied the effects of yaw, instrument acceleration, traversing, and the position of the operator on the handheld vane anemometer frequently usrd in mine airways. €Iaw kins (17.4) devised a vane anemometer that gives a continuous electrical indication of q-ind velocity. Vernotte (69A) discusses
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difficulties in the use of the hot-wire anemometer in the region
of Reynolds nunibers about unity. A portable electric velometer for lowvelocity liquids is described by Misener ( 4 1 A ) . Kindsvater and Carter (9OA) developed an equation that permits the determination of flow of a liquid by observation of the fall in the surface that occurs a t an area constriction of the open channel through which the liquid is flowing. A pulse technique is used by Voice, Bell, and Gledhill (70A) for the determination of gas flow in large ducts a t high temperatures and high or reduced pressures by the sudden introduction of a known amount of radioactive gas. Rumble (548)described an ingenious combination of rotameter and an intcgrally mounted, clock-operated chart for the mcasuremcnt of flow within oil wells a t different levels. A rubber ring, inflatable a t signal, seals the meter t o the casing .crall a t any dcsired point. When pressuie is changing rapidly with time, there is often a significant lag in the transmission of the signal down the connecting tubing. The components of this transmission lag are discussed by Xewman (46,4), who derives a formula for computing the magnitude of the effcct. TranRmission lags can be reduced by the use of electrical transducers, but in high-speed oscillatory phenomena the effects may still be significant. Lamhead ( 5 4 8 ) demonstrates that analytical methods can account for transmission effect, if the amplitude is small; otherwise, experimental data are needed for (1) transmission effect, (2) spurious responses caused by probe, and (3) attenuation due t o gas in liquid-transmission lines. Other inaccuracies that must be guarded against in high-speed oscillatory phenomena are those caused by frcquency dependence of the pick-up calibration, sensitivity to mechanical vibration, and probe effect. FLOW THROUGH POROUS MEDIA
A generally applicable cor1elation for predicting pressure drops during fluid flow through porous media still an aits development. Wag~taffand Nirmaier (3B) made some measurcmcnts for air flow through beds of differently sized wooden blocks and compared their data with values predicted by five different published correlations in an attempt to deduce which formula was most accurate. Their results, however, were inconclusivc, as the measured deviation from values predicted by any individual formula was greater than the deviation in average values between formulas. I t seems probable that a controlling element in these measurcnients n as bed configuration, a statistical concept with which none of the formulas published to date can cope. I n a study of the effect of porosity and particle shapc on the KozenyCarman constants, Wyllie and Gregory (10B) paid careful attention t o the experimental detail of srcuring randomness of packing; they charged their packing mateiial through a threedimensional Galton quincunx and rejected data if the pressure drops measured over each of five sections did not agree within 5%. Their tcchnique involved determination of a tortuosity factor by electrical resistance methods. They concluded that the Kozeny-Carman constant is a marked function of both particle shape and porosity. These investigators point out that the Kozeny-Carman equation is valid only for packings of relatively uniform particle size, as the small particles determine to a great extent the friction-generating surface, whereas the large particles have a greater effect on flow. Another possible source of error in their work is the assumed but unproved relationRhip between electrical tortuosity and hydraulic tol-tuosity. Investigations like these demonstrate the necessity for caution in applying airpcrineability methods for measuring surface a r e a . A novel but simple adaptation of this method has been presented by Kamack
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FLOW OF FLUIDS (6B). Another approach to the problem of specifying bed configuration is made by Happel and coworkers (3B, 4B) who present a mathematical and experimental study of the pressure drop through a cubic assemblage of fixed immobilized spheres. A number of additional complicating factors enter the problem when the fluid is other than 5 homogeneous gas phase. Michaels and Lin ( 7 B )found that the permeability of a kaolinite sediment varied by a factor of 20 to 1, depending upon the fluid used, despite equal void ratios for the measurements. Furthermore, a variation of permeability with voidage disagrecd substantially with the Kozeny-Carnian prediction. Surface flow and electro-osomotic effects entered into the problem t o a certain extent, but thc major cause of the difference is apparently a change in the degiee of agglomeration created by the original huspending fluid. Irmay (6B)suggests that a major factor in the coefficient of permeability for the flow of water through soils is the fact that a portion of the pore water remains stagnant due to re-entrant angles. When gas flow occurs simultaneously with liquid flow, the soil is designated as “unsaturated.” Irmay’s principal conclusion, after a series of mcasuremcnts, is that the ratio of unsaturated t o saturated specific permeabilities varies parabolically with the degree of saturation. A similar situation occurs when the two fluids prescnt in a porous bed are immiscible liquids, such as petroleum and water. Croes and Schwarz ( 1 B ) *how that the per cent displacement of petroleum by water is given as a function of viscosity ratio and quantity of the niixtuie displaced. Their calculations seem to show that relative permeability is a function of the oil saturation and is independent of relative viscosities. They also seem to substantiate the hypothesis that the oil-water interface is a plane surface, perpendicular to the direction of AOT, as opposed to the Dietz theory that the water-oil front consist9 of a curved finger of water. The authors state, however, that both theories are valid in different rangcs of bed thickness. A common chemical-process operation dependent on flox through porous media is filtration. Cunningham, Broughton, and Kraybill ( 2 B ) present their findings on flow through textile filter media. Over a specificd range of air flow, they report that pressure drop can be expressed as AP = kwv; k is further correlated for many materials in terms of cloth weight. A correlation for liquids is difficult t o obtain becauw of the importance of netting characteristics. Tiller has previourly presented a graphical application of the Kozeny function to constant rate filtration. TTe now ( 8 B ) develops an analytical method, similar to his graphical one, but modified to allow for empirically observed changes in the specific filtration resistance greater than that corresponding to the Iiozeny function. MULTIPHASE FLOW
This section is subdivided according to thr varions comhinations of solid, liquid, and gas phases studied. Solid-gas system5 may be further classified according t o the mobility of the solid particles-Le., fluidized beds, moving beds, and gas streams with entrained solids. Solid-Gas Systems. No sound foundation has been laid down, as yet, €or an understanding of the fluidization process whereby the properties and behavior of a fluidized bed may he predicted from considerations of aerodynaniics and simple particle dynamics. One reason for this state of affairs may be found in the rrsults of two papers that rather pointedly demonstrate that frcquently aerodynamic forces may not be the controlling factors in fluidization. Morse (S2C) found that the injection of sonic energy into a fluidized bed may profoundly affect the state of fluidization, while Reed and Fenske (SSC) found that mechanical agitation can also produce marked effects. Morse reports that he could not produce any mensurable changes in fluidization of ordinaiily good fluidizing materials, but he obtained very large improvements for poor fluidizing materials such as plaster of Paris.
March 1956
Frequency, amplitude, and quality of fluidization were interrelated by a complex function. Reed and Fenske inserted screens and perforated horizontal plates into fluidized beds; thc screens and plates were oscillated vertically. In purely fluidized beds a t low air rates, incrcasing frequency caused increases in bed height and in pressure drop, presumably due to a reduction of channeling. Improvement was greatest a t low air rates, indicating that i t was due to a n increase in local gas t o solid velocities. Where the gas velocity was greater than the plate motion, improvement was negligible. From a study of the transient heating of coal particles in a hot gas stream, Wamsley and Johanson (46C) conclude that a fluidized bed cannot be considered equivalent to a uniformly expanded, fixed bed, and that a portion of the entering gas must be regarded as effectively bypassing the solid particles. Henwood and Thomas ( I 7 C ) also report the results of a study of the quality of fluidization of coal. Their conclusions are based on an analysis of pressure fluctuations. A British patent (SdC) has been issued that covers an improvement in the conveying action of gas introduccd through a permeable support by electromagnetically vibrating the support. Under certain conditions, a stream of air injected upwrard into a column of granular material will not cause the bed to fluidize uniformly, but will channel-Le., the air will blow up through the bed in discrete paths in which a low concentration of solids will be transported while the rest of the bed is relatively slow-moving or inert. Mathur and Gishler (SOC) studied the means of generating a single rontrolled channel for the purpose of obtaining some of the advantages of the fluidized bed for materials that cannot ordinarily be fluidized. They describe their system as a new process distinct from fluidization. The results will probably be useful for the claimed objective of improving bed fluidity, but even greater benefits may possibly accrue from the application of their observations to the reduction of channeling in fluidized beds. The paper provides measurements of distribution of air and solids velocity and discusses the effects of bed height, airinlet diameter, column diameter, and inlet-cone angle. Yen process applications of fluidization include a pilot-plant coal-gasification unit (26C), a TI aste-heat boiler (7C) in which the r coils are immersed in a fluidized hed, and an activated charcoal adsorption unit (8C) \vhich is similar in many respects to a bubble-plate toxver. A novel fluid-coking unit (gC) meets the probleni of particle gron th in process by continuously removing the larger particles and replacing them by “seeds” that arc produced by direct grinding. Kithin recent years a number of processes have becn devrloped in which granular solids move downvarrl in a reartor in aerated but unfluidizcd flovr-. Mechanical design of systems of this type is desciibcd by Berg (SC) who discusses reactor solids flow production and control, vapor introduction and removal, solids conveyance and flow control outside of thc reactor, and the application of the system to typical processes. -4 number of investigators have studied t h r flo\v of suspcnsions of solids in gases. With few exceptions, these studies have dealt with practical problems of dust separation. Among the exceptions may be mentioned a Russian paper (382)that constitutes a mathematical investigation of the movement of SUEpended particles in turbulent or laminar flow. Hattersley, Naguire, and Tye (15C) describe an apparatus for the production of dust clouds of relatively constant size distribution and concentration. A chemical process that is conducted in SUEpension is describcd in a British patent (4SC). In this process pulverized metal oxide, carbon, and limestone are entrained in an oxygen-containing gas and reacted a t a temperature above 2000” F. to produce a liquid metal from the oxide and a gas with a high content of carbon monoxide and hydrogen. Small particles may be removed from gas streams by the application of inertial forces, electrostatic forces, or adhesive forces. The best method for any given situation is determined by consideration of particle size, gas rates, and environmental conditions, such
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UNIT OPERATIONS REVIEW diffusion, and settling. Some factors affecting electrostatic precipitator performance in pulverized fuel-fired boilers are discussed by Flodin and Haaland ( I S C ) . A recently issued patent ( I 6 C ) claims that the collection efficiency of a precipitator may be increased if coal of size less than 10 microns is added to the dust in the gas streams in amount of 10 to 20%. Solid-Liquid Systems. No general rules can be given for the measurement of solidliquid flows because of the almost infinite range of properties such mixtures can have. A fairly common type of fluid is typified by setmge. Betz ( 4 C ) describes the problem of metering and controlling raw sludge flow and the solutions to these problems as developed in the Los Angeles continuous semage-treatment plant, Venturis are used with manometer taps continuously purged by metered u ater flows; sludge deposition on the Venturi surfaces make yearly cleaning and relatively continuous flow accounting necessary. Valve positioncrs are adjusted to compensate for the necessary oversixing of valves. Hull (18C) outlines the use of radioactive tracers iri refineries for the mensurement of liquid :?rid solid-flow rate, flow pattern, and mixing rate. Resin kettles demonstrate complexities in valving and piping of modern Hydraulic conveyance of solids, while used dyestuff and organic intermediate manufacturing plant by a number of industries for short-distance conveyance, is still in the very elementary phase of engineering development. Some data on the pumping of raw peat are provided as temperature. Tigges and ICarlsson ( 4 5 C ) discuss methods of by FVilliarns ( 4 7 C ) , n40 reports on the pressure and energy reremoving fines in a high-temperature zone and consider the quired to pump this material through 540 feet of a 6-inch steel effects of the position of the dust-separator upon the general pipeline. A British patent (26C)suggests that, t o produce an efficiency of a furnace. The coal-fired gas turbine has a number easily pumped suspension of coal in water, sufficient colloidal of economic advantages, but its general applicability is restricted clay be added to the water to reduce the settling rate of the solid hy the deteriorating action of the coal ash in the combustion to a specificd value by regulating the viscosity and density of gases upon the turbine blades. Leason ( M C ) discusses recent the swpending fluid. One of the major difficulties associated investigations into methods for removing ash particles from the with hydraulic transportation of solids is wear and erosion of gas. The most generally used inertial type of dust srparator is the pumping equipment. Three patents by Jones ($42)describe the centrifugal or cyclone type. Johnson and others ( S I C ) arrangements for moving the slurry by high-pressure n ater, studied the performance of two types of centrifugal dust collecthereby avoiding direct contact between slurry and pump. tors; each was operated both dry and with water spraj s. They Another paper on hydraulic transportation with a somewhat measured the effect on collection eficiency of various parameters different point of view from those previously discussed is by of the watcr and air flon-s. Depending upon the design, the Hunt ( I Q C ) ,who discusses deposition of silt in open canals. xater may function in one or more of three wajs: (a)its particle A correlation for friction factors of solid-liquid suspensions in conditioner, ( b ) as particle agglomerator or collector by impact, vertical columns was found by Bhattacharya and Roy (5C), who or ( c ) as a wall washer. Part of the improvement in efficiency dcscribe all of their data by an empirical formula relating pressure provided by water sprays is lost by disturbances generated by drop with tube length and diameter and with slurry velocity and the presence of nozzles. Improved application of the inertial concentration. They found by using the type of analysis principles is claimed for a louver-type dust, separator (38C), developcd by Vogt and White for air suspensions, that a simple n nianifoldcd arrangement of several small cyclones (IOC),and equation adequately described their data also, but the equation a device with motor-driven cylinders for increasing the cenembodied a constant that was different for each system studied. tiifugal forces ( 3 7 C ) . Another operating parameter, which lias Orr and Blocker (SSC) suggest that the introduction of two not received much consideration heretofore, is discussed in a constants, one of n-hich is an exponent, into Einstein’s equation pipri ( 1 2 C ) that analyzes the effect of air flow from the solid-disfor dilute suspensions will modify it so that it becomes applicable chaige end on the efficiency of a cyclone dust separator. to concentrated suspensions. They find that their constants are Inertial forces are completely inadequate for the removal of functions of the settled sediments volume fraction and of a particles of subniicron size. In a foundry that produced a geometric standard deviation for size distribution. An evaluasnioke nith an average particle size of 0 061 micron, tcsts made tion of published data provides substantiation of their new forwith various types of collectors led to the choice of a bag-type mula. Starkey (40C) finds qualitative support for his theory that filter with reverse air flow, and a collection efficiency of 99 9 % flow of suspension is controlled by the existence of molecular vortexes of which the suspended particles formed nuclei. In a (ZOC). A paper by Chen ( 9 C ) provides a comprehensive review of particle filtration by fibrous media. In this review, a discusstudy of dispersions of calcium carbonate (0.1 to 0.4 micron) in sion of flow patterns around isolated cylinders is followed by an polybutene oil, Zettlemoyer and Lower (48C)find that the smaller analysis of collection efficiency by inertia, interception, Brownian particle sizes cause an increase in viscosity a t a given loading,
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FLOW OF FLUIDS particle-size distribution has no effect; surface-active agents reduce the viscosity. They explained these effects as being due to a layer of vehicle, which is immobilized on the surface of the particle thereby increasing the effective particle volume prcportional to the surface of solids prescnt. These observations seemed to be in disagierment with those of Orr and Blocker who say that size, not distribution, is important; however, the sizes ronsidered by the two groups of investig:itor s are quite cliff erent. The economic importance of separating solids from fluids is being inci easingly emphasiaed, both in recovery of valuitble solids and in minimizing w.tter pollution. -4mechanical means for accomplishing this separation is discussed by Teuteberg (4ZC), who describes the functioning of a centrifugal separator consisting of a housing containing a hello\\ rotor and filled with a heavy medium suspension and an aqueous suspension Aith a clear adjustable boundary between the two. Methods of designing thickeners and scttlers are discussed by Talmadye and Fitch (41C). Settling and concentration take place through several different types of lnycrs The capacity of an) thickening unit is determined by the slowest of these layers The authors show how adequate consideration must be given to this controlling layer and that sizable errois are possible if the design is based only on the initial settling rate Comings, Pruiss, and DeRord (11C) developed general expressions for hindered settling oi nonflocculent slurries. They find that the mechanism of settling under slow stirring apparently differs greatly from the mechanism of settling mithout stirring and that therefore, hatch settling tests can be applied to practical designs of thickeners only x+ith the greatest caution. Thompsou and Vilbrandt (44C) have studied the effect of ultrasonic energy on the settling of solids and report that an intensity below the cavitation level increased coagulation and settling rate 5 times, whereas an intensity above the cavitation level broke up agglomerates, increased thixotropy, and retarded settling. Gas-Liquid System. Study of the flow of gas-liquid mixtures is complicated by the multiplicity of physicat forms in which these systems can appear. Thus, the degree of turbulence of the gas and the liquid phases are independently determined; and flow can proceed as a mixture of bubbles and liquid, as a mist, as dugs, as an annular arrangement of liquid about the gas, etc. Johnson ( d 2 C ) provides some data for viscous-turbulent flow of oil and air mixtures in a steam-heated, horizontal pipe. From an industrial viewpoint, one of the most important gas-liquid systems is the steam-nyater combination occurring in boilers. Koel (S7C) develops formulas for the calculation of pressure drop in tubes in which evaporation is occurring, The theory is applied to the stability problem of parallel evaporation tubes of steam boilers. Hahnemann ( l 4 C ) discusses an experimental investigation into the density distribution, the water and steam velocity, and pressure drop in vertical and horizontal tubes of boilers. In vertical tubes, the steam always flo~vsin the center of the tube, even a t very high load, the tube wall is covered with nater and overheating is unlikely. I n horizontal tubes, watrr and steam separate after travprsing a length of a few tube diameters, so that the upper part of the tube may easily become overheated. Data are provided for the relative velocity of steam and n ater as affected by load and pressure, and for friction cocfficicnt of watersteam mixture. A mathematical study of the behavior of water globules in steam is undeitaken by Ryley (56C), n-ho estimates the time and distance required by a miter particle to reach 90% of its terminal velocitv hen falling in a stlearn of steam. He also computes the incidence of fracture of particles n-hen either their size or their velocity relative to the gas exceeds a critical value. A British patent ( I C ) details some fluid paths that are effective in separating steam and water. The difficult problem of accurately metering the flow of saturated boiler water is undertaken by Monroe ( S I C ) who passes the stream through a series of knife-edged orifices and develops an equation that gives the relationship among the number of orifices in series, mass-flow,
March 1956
viscosity, temperature, density, and pressure drop across all the orifices. Chemical processes which are highly dependent for their operability upon proper bubble flow are absorption and distillation in packed towers. Leva, Lucas, and Frahnie (SOC) show that flooding is greatly influenced by the ability of the packing support plate to permit disengagement of bubbles from the liquid. Their criterion for proper design is the change in pressure drop across the plate when a single layer of packing is applied. Another important application of the interaction of liquid and gas is the atomization of liquids. Ritron ( 6 C ) finds that the Sukiyania-Tanasam a equation of size distribution may be extended into the supersonic air velocity range The use of the Venturi atomizer for aerosol collection is irivcstigated by Johnstone, Feild, and Tassler (R3C) Rho analyzed the effect of inertial forces, electrostatic forces, and Brownian movement on small particles, antl showed that for the Venturi atomizer, inei tin1 impaction is the major effective mechanism. This v a s suhstantiatcd by finding that collection efficiency is controlled by the geometry and the size and density of the particles and not 11y the nature of the aerosol-i.e., an equivdent collection eficienc.y was obtained for a \vnter-soIuble mist antl a hydrophobic oil. MECHANICAL DESkGN
This section is subdivided into discussions of metering from the viewpoint of mechanical design as distinguished from fluiddynamic considerations in previous sections, discussions of prohlems common to all types of pumps, such as cavitation, stresses, and bearing construction, and discussions of the various in& vidual types of pumps and equipment. Metering. Seven paper8 from a symposium on nictcring and control of fluid and solids flou are reviewed by Glasheen ( I f D). These papers include discussion of turbine-type flom meters, rontrolled-volume pumps, the use of gamma radiation and strain gager in various measurements, gravimetric feeders for solids, and the iisc of differential transformers in various instruments. Another type of pressure-sensing instrument, involving capacity changes, is described by Frank and Gibson (101)). Cusick ( 6 D ) outlines general factors to be considered in deciding where to put meter bodirs and in installing piping and accessories. Testing large steam turbines can be an expensive operation, hut Pollock (1Q1)) explains the costs and henpfits obtainable from more accurate hnowledge of turbine performance. He shows that where neigh tanks can he integrated into the flow cycle, their additional cost is more than offset by the benefits from inrreased accuracy in analysis of the turbine performance, General Considerations. The creation and collapse of vapor bubbles n ithin a liquid pump ronstitutes the phenomenon of cavitation which can create serious erosion problems in high-speed impellers and has very deleterious efrects on the performance of several types of pumps. -4 rewin(’ of the present status of cavitation research R i presented by Iinapp (141)). Baron (ID) shows how to anticipate and prevent the sudden onset of cavitation that occasionally occurs in the recirculating type of boilcrfeedwater pumps. Water-tunnel experiments by Kermeen and roa-orkers (131)) show that the inception of cavitation depends not only on flow parameters but also on the model scale velocaity and hydrofoil shape. Hysteresis effect was also notcd- i e., the pressur? t o start cavitation nyas lower than that necessar? to maintain it. Ferro (91)) shows both experimentally and theoretically that for high-lift pumps cavitation may cause a sudden change in flow fiom normal to zero. He compared the formulas of six different authors and found fairly good agreement with expeiimentnl noih a t high head and low flows, but large deviations a t Ion suctions and high flous. Chilton and IIandley (SD)developed design methods for gascushioned surge tanks for liquid pumps in which they computed the relative pulse amplitude for various types of reciprocating pumps as a function of displacement over surge-tank volume
INDUSTRIAL AND ENGINEERING CHEMISTRY
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UNIT OPERATIONS REVIEW Piping design problems associated with internal conditions of temperature and pressure are now well resolved. Changes in these conditions with time, however, make themselves manifest in piping stress. The first of a series of thrce papers intended t o provide a simple method of analysis of piping flexibility problems has now appeared (240). This method is of adequate accuracy for common applications. The combined stresses produced by fluid pressure plus that produced by thermal gradients are emphasized in nuclear plants because of the high heat generation within the material and because of the use of unfamiliar materials. Langer ( 1 6 0 ) s h o w , however, that thermal stresses are generally self-relaxing and hence the combined stresses are frequently less than expected for simple addition. Where thermal cycling is encountered, these calculations evplain previously observcd anomalies of tube endurance well above steadystate fatigue limits. Other aspects of the mechanical design of nuclear reactors cooled with liquid metal are discussed by Stahl ( W D ) . Several other piping problems have been relieved by the commercial development of plastic piping, valves, and duct work. Seymour ($OD) discusses the choice of a proper plastic for various duties in respect to cost, temperature resistance, and chemical resistance. Evaluations of pumps should be based not only on hydraulic requirements, but also on the mechanical design of bearings, shafts, etc., in reference to duty requirements. Ullock ( 2 5 0 ) outlines methods for calculating bearing loads, shaft deflections, and proper bearing protection, and explains how these are affected by fluid propcrties. Proper repair and reassembly of pumps is discussed. Norton ( l 8 D ) details 13 ways to solve various packing problems, including control of abrasives, lantern ring and flushing fluid control, excessive shaft deflection and wear, and deterioration of packing and seals. Pumps and Compressors. A symposium on centrifugal compressors ( 4 0 , 60,8D, 16D, 17D, 21 D, E?D)provides in relatively simple but considerably detailed terms the theory of operation, important performance characteristirs, process and mechanical design, specifications and selection, and operation and maintenance. The Johnston Pump Co. has issued a reference book (eo)providing similar but more dctailed coverage on vertical turbine and propeller pumps. A pump that has come into recent proniinence because of its advantages p;ith respect t o Cost and ability to handle mixtures of gases, liquids, and solids, has been variously called the periphery, turbulence, friction, turbine pump, or regenerative pump. The geometry and performance of this pump are discussed by Wilson and Santalo (27D). Iversen ( l d D ) analyzes its performance in terms of shear-stress coefficients and vane velocity in agreement with the originally assumed mechanism that the pump operates by frictional drag of the fluid. I n the formal discussion of this paper, exception was taken to this simple mechanism and the hypothesis was advanred that the action is due to local centrifugal action of flow within pockets of the vanes. A newly availahle pump ( d 6 D ) is capable of handling suspensions of abrasive, friable, or ‘[oveisize” materials. The fluid is moved by centrifugal forces imparted by a vortev created by an impeller that is out of the line of flow so solids do not have to pass through this impeller. A high-vacuum pump ( 7 D ) , capable of removing large quantities of gas a t extremely low pressures, has eliminated the use of organic vapors and high-vapor pressure materials by utilizing the evaporation of titanium.
Bibliography SINGLE-PHASE FLOW
(1A) Acharaya, Y.V. G., A&. Sci. Res. -4-5, 4 (1955).
(2A) Amos Research Staff, Natl. Advisory Comm. Aeronaut. Repts., 1135 (1953). (3A) Berry, C. H.,“Flow and Fan,” Industrial l’ress, New York, 1954. (4A) Bleines, W., Bauingenieur 29,339(1954).
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(5.4) Bohnet, W. J., Stinson, L. S., Trans. Am. SOC.Mech. Engrs. 77, 683 (1955). (6A) Coke and Gbr 16,323 (August 1954). (7A) Corey, T. L., Kip, E. M., Machine Design 27,189(March 1955). (8A) Daugherty, R. L., Ingersoll, A. C., “Fluid Mechanics With
Engineering Applications,” 5th ed., McGraw-Hill, New York, 1954. (SA) Dorrance, W.H., Dore, F. J., J . Aeronaut. Sci. 21,404 (1954). (10A) Drhimsheli, G.A.,Cddrotekh. StroiteE. 22, No. 11, 36 (1953). (11A) Eckert, E. R. G., Diaguila, A. J., Donoughe, P. L., Natl. Advisory Comm. Aeronaut., Tech Note 3339 (1955). (12A) Ferrell, J. K., Richardson, hl., Beatty, K. O., Jr., IND.ENG. C H E M . 29 ~ ~(1955). , (13A) Gill, F., Russell, R. J., Ibid., 46, 1264 (1954). (14.4) Grassmann, P., Hildesheimcr, II., Chem.-Ing.-Tech. 26, 601 (November 1954). (15A) Hahnemann, H. W..Ehret, L., Forsch. Gebiete Ingenieurw. 20, No. 5,141; No. 6,171 (1954). (16.4) Haughton, C. B.,Gorton, R. E., Am. Soc. Mech. Rngrs. Paper54-A-113 (1954). (17A) Hawkins, A.E., S&.Instr. 31,404 (1954). (18.4) Helander, L., Yen, S. M., Knee, L. B., Heating, Piping Air Conditioning 26,141 (September 1954). (19A) Hereig, H. Z., Hansen, A. G., Trans. Am. SOC.Mech. Engrs. 77, 249 (1955). (20-4)Hobson, M., Weber, J. H., IND.ENG.CHEM.46, 2290 (1954). (214) Hoerner, S.F., J . A m . SOC.NavaE Engrs. 66, 497 (May 1954). (22.4) Hutton, S. P., Proc. Insl. Ciuil Enps. 3, part 3, 216 (April 1954). (23-1)Ibing, R., Z.Ver. deut. Ing. 96,1085 (Nov. 11, 1954). (24-4)Isakoff, S. E.,IND.HNG. CHEM.47, 413 (1955). (25.1) Jackson, M. L.,J . Am. Inst. Chem. Engrs. 1, 231 (June 1955). (%A) Jorissen, B L., Am. SOC.hlech. Engrs., Paper 54-A-I90(1954). (27A) Juhasz, S.l.,Ibid., 54-A-137(1954). (28A) Kaufmann, W., “Technische Ilydro- und Aeromechanik,” Springer-Verlag. Berlin, 1954. (29.2) Keyes, F. G., Keenan, J. €I., Am. SOC.Rlech. Engrs. Paper 54-A-237(1954). (306) Kindsvater, C. E., Carter, R. Tir., Proc. Am. Soc. CioiE Engrs. 80,Separate 467 (1954). (31-4)Knapp, W.C., Meteger, J. W., Trans. A m . SOC.Mech. Engrs. 77,675(1955). (32.4) KoesteS, A., Heatiw, . Piping . . Air Conditioning 26, 143 (June 1954). (33 2) T,aitone, E. V., PubEs. sci. et tech. niinistlre air (France) 203, 1954. (34-4)Lawhead, R. B.,IND. ENG.CHmf. 47, 1184 (1955). (356) RlachliUan, F.A., J.Roy. Aeronaut. SOC.58,570 (August 1954). (36.1) hIain-Smith, J. D., Aeronaut. Research Council London Rep. Mem. 2755, February 1950,publd. 1954. (379) Martin, M., Am. SOC.Mech. Engrs., Paper 54-PET-10,1954. (38.1) Jlay, J. A., Frank, J. C., Chem. Eng. Progr. 51, 189 (1955). (396) MerrilS, E. W.,J . Colloid Sci. 9,132 (April 1954). (40-\)Miner, I. O.,Am. SOC.Mech. Engrs. Paper 54-A-139,1954. (41-4)Misener, A. I)., Can. J . Technol. 32, 242 (November 1954). (42.1) Munk, P., PetroZeumRefiner 34, 104 (July 1955). (434) Murdock, J. W.,Faltz, C. J., Gregory, C., Jr., Am. SOC. Mech. Engrs. Paper 54-A-122,1954. (44.1) Narayanamurti, D., Handa, B. K., KoEZoid Z., 135, 140 (March 1954). (45.1) Newman, B. G., Natl. Aeronaut. Establ. Canada. LR-100, Ami1 1954. (46.2) Oppkheim, A. K., Cliilton, E. G., Trans. Am. Soc. Mech. Engrs. 77,231 (1955). (47-1)Prengle, R. S., Rothfus, R. It., Ixu. KNG. CHEM.47, 379 (1955). (48A) Reese, B.A.,Graham, B. W., Katl. Advisory Comm. Aeronaut., Tech. Notes3181,1954. (49-4)Rivas, 11. A , , Shapiro, A . €€., Am. SOC.Mech. Engrs., Paper 54-A-98,1954. (50A) Roberts, R. W., Corneli, D., Petroleum Refiner 34, 141 (July 1955). (51A) Ross, D., Ani. SOC. Mech. Engrs., Paper 54-A-89,1954. (524) Rothfus, R. R., Nonrad, C. C., IND.ENG. CHEM.47, 1144 (1955). (53A) Rothfus, R. It., others, Ibid., 47,913 (1955). ( M A ) Rumble, R. C.,J . Petrolezrin Technol. 7, 53 (March 1955). (55A) Sandborn, V. 9..Natl. Advisory Comm. Aeronaut. Tech. Kotes, 3266,1955. (56A) Shapiro, A. H., “Dynamics and Thermodynamics of Compressible Fluid Flow,” Ronald Prcss, Kew York, 1954. (57A) Sherlock, R.H.,Lcsher, E. J., Trans. Am. SOC.Mech. Engrs. 77, l(1955). (58A) Sherwood, T. K.,Chern. Eng. Progr. 51, 303 (1955). (59A) Silber, R., “atude et Trace des acouleinents Permanents en Canaux et Rivibres,” Dunod, Paris, 1954.
INDUSTRIAL AND ENGINEERING CHEMISTRY
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FLOW OF FLUIDS Strom, G. H., Halitsky, J., h I . SOC.hlech. Engrs. Paper 54SA-141,1954. Sukkar, Y. K., Cornell, D., Am. Inst. Mia. Engrs. Petroleum Trans. 204,43 (March 1955). Swirles, J., Colliery Eng. 31, 508 (December 1954). Tao, L. N., Donovan, W., Am. SOC. hlech. Engrs. Paper 54-A-175,1954. Teofilato, s., Publs. sci. et tech. ministbre air (France) 319, 1954. Thibessard, G., Reu. universelle mines 10, 38 (February 1954). Thrasher. L. W., Binder, R. C., Instruments and Butoination 27,1810 (November 1954). Thring, 111. W.,Heating and Ventilating Engineer (London) 28, 23 (July 1954). Umholtz, C . L., Tan Winkle, hf,, Petroleum Refiner 34, 114 (July 1955). Vernotte, P., I‘ubls. sci. et tech. ministdre air (France) 407, 1954. Voice, E. W., Bell, E. B., Glcdhll, P. K., J . Iron Steel Znst (London) 177,423 ( A u w s t 1954). Wenger, F., Anal. Chim. Acta 11, 229 (September 1958). Zarek, J. &I., Engineering 179, 17 (Jan. 7, 1955). THROUGH POROUS MEDIA
Croes, G. A., Schwarz, h*.,A m . Inst. Jdin. Engrs. Petroleum Trans. 204,35 (Marrh 1955). Cunningham, G . E., Rrougtiton, G., Iiraybill, R. 1L. IND. ENG.CHEM. 46,1197 (1954). Happel, J., Byrne, B. J., Ibid.,46,1181 (1954). Happel, J., Epstein, K.,Zbid., 46, 1187 (1954). Irmay, S., Trans. Am. Geophys. Union 35, 463 (June 1954). Kamack, B. J., Anal. Che9hem. 26,1623 (1954). Michaels, A. S.,Lin, C . s.,IND.ENG.CHEJI.46, 1239 (1954). Tiller, F. M., Chem. Eng. I’rogr. 51,282 (1955). Wagstaff, J. B., Sirmaier, E. A., INn. ENG.C m x 47, 1129 (1955). Wyllie, M. It. J , Gregory, A. R., Ibid., 47, 1379 (1955).
(25C) Kansas City Testing Laboratory, Brit. Patent 716,911 (Appl. date Aug. 29,1952). (26C) Kennar, G. A., Moulton, R. W., Trend. Eng. Univ. Wash. 6 , 9 (October 1954). (27C) Koel, J. C., Ingenieur 66, No. 13, W. 19 (March 1954). (28C) Lcason, D. B., Research 8, 22 (January 1955). (29C) Leva, M., Lucas, J. hf., Frahme, H. H., IND. ENG.CHEW46, 1225 (1954). (30C) Mathur, K. B., Gishler, P. E., J. Am. Inat. Chem. E n v s . 1, No. 2, 157 (1955). (31C) Monroe, E. S., Am. SOC. Mech. Engrs., Paper 54-A-118, 1954. (32C) Morse, R. D., IND. ENG.CHEX 47, 1170 (1955). (33C) Orr, C., Jr., Blocker, H. C., J . ColEoid Sci. 10, No. 1, 24 (1955). (34C) Polysius G.m.b.H., Brit. Patent 712,593 (Appl. date Dec. 5, 1952). R., IND.ENG.CHEM.47, 275 (35C) Reed, T. hI., 111, Fenske, (1955). (36C) Ryley, D. J., Engineer (London) 198, 74 (July 1954). (37C) Simon, H., Ltd., others, Brit. Patent 717,848 (Appl. date Jan. 7, 1952). (38C) Slezkin, N. A., Shustov, S.K., Doklady Akad. Nauk. S.S.S.R. 96, S o . 5, 933 (June 1954). (39C) Smith, J. L., Goglia, 31. J., Am. Soc. Mech. Engrs., Paper 54-A-134, 1954. (40C) Starkey, T. V., Brit. J.A p p l . Phys. 6, 34 (1955). (41C) Talmadge, W. P., Pitch. E. B., IKD.ENG.CHEM.47, 38 (1955). (42C) Teuteberg, R., (Jlzickauf 90, 1276 (Scpt. 25, 1954). (43C) Texaco Developrncnt Corp., Brit. Patent 712,929 (Appl. date Feb. 8, 1951). (44C) Thompson, D., T’ilbrandt, F. C., IND.ENG.CHEX 46, 1172 (1954). (45C) Tigges, A. J., Karlsson, I$., Am. SOC.Mech. Engrs., Papcr 54-A-247, 1954. (46C) Wamsley, W. IT., Johanson, L. N., Chem. Eng. Progr. 50,347 (1954). (47C) Williams, E. E., Intern. Peat Symposium, Dublin, July 12, 1954; abstracted in ,J. Inat. Fuel 27, 567 (Nov. 1954). (4%) Zrttlemoger, A. C., Lower, G. W., J . CoZZoid Sci. 10, No. 1, 29 (1955).
MUTIPHASE FLOW
(IC) Babcock and Wilrox, Ltd , Brit. Patent 719,837 (Appl. date July 6, 1951). (2C) Barr, F. T.. Jahnig, C. E. Chem. Eng.Progr. 51, 167 (1955). (3C) Berg, C., Ibid.,51,326 (1955). (4C) Bets, J. h‘l., Instrumentdon8, S o . 1 , 7 (1955). (5C) Bhattacharya, A., ltoy, A. N.,IKD.ENG.CHEhf.47, 268 (1955). (6C) Bitron, M. D., Ibid., 47, 23 (1955). (7C) Campbell, 0. F.. Am. Soc. IIech. Engrs. Paper 54-A-20, 1954. (8C) Chem. Eng. 62, KO.3, 120 (1955). (OC) Chen, C. Y., Chem. Reis. 55, S o . 3,595 (1955). (IOC) Coke and Gas 16,497 (December 1954). (1lC) Comings, E. W., Pruiss, C. E., DeBord, C., ISD.ENG.CHCM. 46,1164 (1954). (12C) Ebbenhorst-Tengbcrgen, 11. J., van, h i . Soc Ilech. Engrs , Intern. Air Pollution Congr , Paper 55-APC-8, 1955. (13C) Flodm, C. R., Haaland, H. IT. Am Soc. Mech. Engrs. Paper 54-A-212,1954. (14C) IIahneniann, 11. W , Z.Ver. deut. Zng. 96, 1016 (Oct. 21, 1954). (15C) Hattersley, G., Maguire, B. A., Tye, D. L., Ministry in Fuel and Power, Safety in Mines Research Fstab., Research Rept. 103, Septemher 1984. (16C) Hedberg, C. W. J., Brook, B.. Winterniute, H., U. S. Patent 2,677,434 (-\ppl. date Dec. 27, 1950). (17C) Henwood, G. A., Thomas, D. G. 8., Instrumentation Practice 8,606 (July 1954). (18C) Hull, D. E., Nurleonics 13, 18 (April 1955). (19C) Hunt, J. N., Proc. Roy. SOC.A224,322 (1954). (20C) Industry and Power 67,51 (November 1954). (21C) Johnson, G. A., othcr8, Chem. Eng. Progr. 51, 176 (1955). (22C) Johnson, H. A,, Am. SOC.hfech. Engr. Paper 54-A-150, 1954. (23C) Johnstone, H. F., Feild, R. R., Tassler, M. C., IND. EXG.CHEX 46,1601 (1955). (24C) Jones, S. A., Reichl, E. H., U. S. Patent 2,672,370; 2,672,371 ; 2,672,372 (Appl. Jan. 15,1951).
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MECHANICAL DESIGN
(1D) Baron, S., Power Eng. 58, KO,7, 75 (1954). (2D) Chem. Eng. Progr. 51, No. 4, 24 (1955). (3D) Chilton, E G., Handley, L. R., Trans. A m Soc. Mech. Engrs. 77, 225 (1955). (4D) Cole, S. L., Peet, G. D., Petroleum Refiner 34, No. 1, 140 (1965). (5D) Crego, D. F., Ibid., 34, No. 1, 143 (1955). (6D) Cusiek, P.,Instrumentation 7, No. 4, 44 (1954). (7D) Daviq, R.II., Divatia, A . S , Rea. Sci. Znstr. 25, 1193 (1954). (8D) Erb, 11. A , Petroleurn Refiner 34, No. 1, 123 (1955). Ingegnere (Milan) 29, No. 1, 9 (1955). (9D) Ferro, -4., (10D) Frank, W.E., Gibson, R. J., J . Franklin Indt. 258, No. 1, 21 (July 1954). (11D) Glasheen. R. W., Chem. Eng. Progr. 50,487 (1954). (12D) Iversen, H. W., Trans. A m . SOC.Mech. Engis. 77, 19 (1955). (13D) Kermeen, K.W..McGraw, J. T., Parkin, €3. R., Ibid., 77, 533 (1955). (141)) Knapp, R T., Mech. Eng. 76, 731 (1954). (15D) Langer, 13. F.,Trans. Am. Soc. Mech. Engrs. 77, 661 (1955). (16D) Latimor, T. P., Petroleum Refiner 34, KO.1, 130 (1955). (17D) Lowell, W.O., Ibid.,34, KO.1, 118 (1955). (18D) Norton, R. D., Chem. Bng 62, hTo. 3, 183 (1955). (19D) Pollock, W.A , Trans Am. Soc. Mech. Engrs. 77, 79 (1955). (20D) Seymour, X.B., IND.ENG.C m m 47, 1335 (1955). (21D) Shields, C., Petroleum Refiner 34, No. 1, 132 (1955). (22D) Smith, 0. A., Ibid., 34, KO. 1, 136 (1965). (23D) Stahl, C. R., Am. SOC.Mech. Engrs., Paper 54-SA-60, 1954. (24D) Tube Turns Research Staff, Piping Engincering, FiIe 4.03, April 1955. (25D) Ullock, D. S., Chem. Eiag. Progr. 51, 207 (1955). (26D) Western Machinery Comp., San Francisco, Calif., Bull. PSB10, 1955. (27D) Wilson, W. A., Santalo, h‘l. A., Am. SOC.RIech. Engrs., Paper 54-A-60, 1954.
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