I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
1952
Vol. 46, No. 9
ACKNOWLEDGMENT
The authors thank E. I. du Pont de Kernours & Co. for financing this investigation. N OMENCLATCJRE
R
TEMPERATURE,
Figure 14.
"F.
Thermal Conductivity o f Fin Oil
thermistor constant in absolute tempemture (it actually had a small positive temperature coefficient) D1 .- outside diameter of inside cylinder, 0.9972 =k 0.0003 inch 112 = inside diameter of outside cylinder, 1,1272 rt- 0,0003 inches k~ = thermal conductivity, B.t'.u. per hour (square foot) ( ' F.) per foot k, = thermal conductivity of aluminum, 120 13.t.u. per hour (square foot)( F.) per foot I, = iengbh of test section, 1.9764 inches i 0.4% iyGr = Grashof's modulus XP,.= Prandtl'ii modulus = rate of heat flow, B.t.u. per hour = resistance a t absolute t'emperature ?', ohins Rn = resistance a t absolute tempcrat'ure T o ,ohms S = shape factor for conduction in feet (a function only of the ayea of the fluid perpendicular to the heat, fiow and the distance the heat flows through the liquid) T and T o = absolute temperatures At = temperature difference T - 2'0, degrees F%hr.ctrlrt.it A . ~ L = temperature drop acroes liquid 1ayc.r = thickness of liquid layer, 0.0650 inch ZL za = tbickncas of aliiminum =
k
TEMPERATURE,
O F
Figure 15. Thermal Conductititg of Circo XXX Heat Transfer Oil
LITERATGRE CITED
3:.
8ZO" my
55
TEMPERATURE,
OF.
Figure 16. Thermal Conductivity of Aroclor 1254
reported by Riedel (18). Here again, the value a t the highest temperature, 162' F., is probably about 2 per cent high, owing to was 1400. convection, as (iVprN~r) The data for olive oil (Figure 10) are in excellent agreement with those reported by Kaye and Higgins ( I S ) , D a v k ( 9 ) , and B o a s (7). In the case of Aroclor 1248 (Figure 11) a t 102" F., the author's value agrees within 3% with t h a t found by Smith (do), b u t it differs a t higher temperatures. T h e authors found a decrease with increasing tempwature, whereas Smith reported a very slight increase. CO~C1,USIONs
It i,i believed that the data obtained in this investigation contain errors of less than 2.501,, except for three liquids where the values for the highest temperature were about 2% high, owing t o convection. The data obtained with water proved that the experimental apparatus and procedures I\ ere reliable; th(3 largest measurement errors were associated with the use of u atrr in the annulus. D a t a were obtained for five liquids which had not been previously studied (Figures 12 to 16): Dowthelm A, Dowtherm E, Gn oil, Circo XXX heat transfer oil, and cZroclor 1254. Previously published data for olive oil, Dater, and Aroclor 1248 were substantiated by this investigation. Some disagreement was found in the data for carbon tetrachloride, chloroform, glycerol, ethylene glycol, propylene glycol, and trichloroethylenr. These discrepancics were partly due t o the purity of the sample7 used by the various investigators.
(1) Bates, 0 . K., I N D . ENG.CHEM.,25, 431 (1933). (2) Bates, 0. K., IND.EXG.CHEM.,ANAL,ED., 8, 494 (1936). (3) Bates, 0 . I
