Article pubs.acs.org/jced
Cite This: J. Chem. Eng. Data XXXX, XXX, XXX−XXX
Measurement of Viscosity of cis-1,1,1,4,4,4-Hexafluoro-2-butene (R1336mzz(Z)) by Tandem Capillary Tubes Method Md Jahangir Alam,† Akio Miyara,*,‡,§ Keishi Kariya,‡ and Konstantinos Kostas Kontomaris∥ †
Graduate School of Science and Engineering, Saga University, Saga 840-8502, Japan Department of Mechanical Engineering, Saga University, Saga 840-8502, Japan § International Institute for Carbon-Neutral Energy Research, Kyushu University, Fukuoka 819-0385, Japan ∥ Chemours Fluorochemicals R&D, Wilmington, Delaware 19899, United States ‡
ABSTRACT: The principal goals of the present work are to measure the viscosity of vapor and liquid cis-1,1,1,4,4,4-hexafluoro-2-butene (R-1336mzz(Z)) and propose simplified correlations of the extracted data under saturation conditions for industrial design and simulation. R-1336mzz(Z), a hydro-fluoro-olefin with a low global warming potential and attractive environmental properties, can be considered as a potential working fluid for high-temperature heat pumps and organic Rankine cycles. Nevertheless, reliable experimental R-1336mzz(Z) viscosity data are lacking. This study presents R-1336mzz(Z) viscosity data measured by a tandem capillary tube method at temperatures from 314 (40.85 °C) to 434 K (160.85 °C) and 375 (101.85 °C) to 475 K (201.85 °C) for liquid and vapor phases, respectively, at pressures up to 4.06 MPa. Total standard uncertainties in liquid and gas viscosity measurements were lower than 3.04 and 3.21%, respectively.
1. INTRODUCTION Awareness of the potential impact of refrigerants with high global warming potential (GWP) on the Earth’s climate has been increasing in recent years. Conventional refrigerants such as hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs), and their mixtures have high GWPs1 and necessitate the introduction of more environmentally sustainable replacement refrigerants for use in common applications including heat pumps and organic rankine cycles (ORCs). Hydro-fluoroolefin (HFO) refrigerant R-1336mzz(Z) is now of great interest to researchers as a potential working fluid with favorable properties including low toxicity, no flammability, short atmospheric lifetime, zero ozone depleting potential (ODP), and low GWP.2−7 It has been introduced as the main component in R-514A, as a refrigerant for air-conditioning chillers,8 and as a working fluid for high-temperature heat pumps,9 and ORCs.5 Therefore, physical properties of R1336mzz(Z), such as viscosity and thermal conductivity, have become of increasing interest in designing practical R1336mzz(Z) applications. The molecular structure and basic thermophysical properties of R-1336mzz(Z) are presented in Figure 1 and are listed in Table 1, respectively. R-1336mzz(Z) has an atmospheric lifetime of 22 days and a global warming potential (GWP) of 2,10,11 which are much lower than those of others such as R-245fa used in similar applications. The ozone depletion potential (ODP) of R-1336mzz(Z) is zero. It belongs to safety class10,12 A1 (low toxicity, no flammability) according to ASHRAE Standard 34. The above basic thermophysical properties are strong evidence of the smaller environmental impact of R-1336mzz(Z). © XXXX American Chemical Society
Figure 1. Molecular structure of R-1336mzz(Z).
Table 1. Thermophysical Properties of R-1336mzz(Z) parameters
value
reference
chemical formula CASRN critical temperature (K) critical pressure (MPa) critical density (kg m−3) molecular weight (g mol−1) flammability boiling point (K) atmospheric lifetime ODP GWP (100 year)
CF3CHCHCF3 692-49-9 444.50 2.895 507 164.056 nonflammable 306.55 22 days 0 2
Tanaka et al., 20173 Tanaka et al., 20173 Tanaka et al., 20173 Kontomaris, 201410 ASTM E681-200413 Kontomaris, 201410 Myhre et al., 201311 Kontomaris, 20128 Myhre et al., 201311
As a consequence, the experimental thermophysical properties of R-1336mzz(Z) are required to assess its feasibility as a working fluid in commercial systems. Alam et al.2 presented experimental liquid and gas R-1336mzz(Z) thermal conductivReceived: January 11, 2018 Accepted: March 30, 2018
A
DOI: 10.1021/acs.jced.8b00036 J. Chem. Eng. Data XXXX, XXX, XXX−XXX
Journal of Chemical & Engineering Data
Article
Figure 2. Schematic flow diagram of a tandem capillary tube viscometer.
ity data by well-known transient hot wire method at temperatures from 314 (40.85 °C) to 496 K (222.85 °C) and pressures up to 4.00 MPa. The pρT properties, critical parameters, vapor pressure, saturated liquid, and vapor density were measured by Tanaka et al.3,14 In addition, Akasaka and Lemmon15 delivered a Helmholtz energy equation of state for R-1336mzz(Z). Proper knowledge of viscosity and thermal conductivity of test fluid is necessary to design the heat exchangers to describe its flow behavior, convection characteristics, and two-phase heat transfer and pressure drop.16 In conclusion, viscosity is an important physical property to design this fluid for the purpose of commercial area, but there is no experimental data so far in the literature. Therefore, in the present study, the liquid and vapor viscosities of R-1336mzz(Z) were measured using the tandem capillary tubes method at temperatures from 314 (40.85 °C) to 434 K (160.85 °C) and 375 (101.85 °C) to 475 K (201.85 °C), respectively, for pressures up to 4.06 MPa. The correlations expressing the saturation viscosity of R-1336mzz(Z) were obtained from the experimental data by extrapolation method.
η=
πa 4ΔP 8Lq
(1)
where q is the flow rate of test fluid. It is surprising that radius a is raised to the fourth power in the above Hagen−Poiseuille equation, which means any change in the radius of a tube has a very large effect on viscosity. By considering kinetic energy and end effects, the Hagen−Poiseuille equation can be written as follows η=
mρ q πa 4ΔP − 8q(L + na) 8π (L + na)
(2)
where n and m are the correction coefficients of pipe end and kinetic energy, respectively, and ρ represents the density of test fluid. In the apparatus, two capillary tubes with different lengths are connected in series to eliminate the pressure drop at both the inlet and the outlet of the tube, and thus this method enables us to measure with better accuracy than the single capillary tube method. In the tandem capillary tubes method, the test fluid flows under a laminar flow (the range of Reynolds numbers are from 300 to 1300) condition. For this method, eq 2 can be written as the following
2. EXPERIMENTAL MEASUREMENT 2.1. Principle of Tandem Capillary Tubes Method. The viscosity of test fluid was measured by tandem capillary tube viscometer in this study. The capillary tube method is a technique of determining the viscosity from a measured value of the pressure drop of test fluid flowing in a laminar flow and is one of the most established measuring methods based on the Hagen−Poiseuille theory. The relationship between viscosity η and pressure drop ΔP of a fluid flowing through a horizontal tube of radius a and length L is presented by the following equation of Hagen−Poiseuille as
ηl =
mρ q πal 4ΔPl − 8q(L l + nal) 8π (L l + nal)
(3)
ηs =
mρ q πas 4ΔPs − 8q(Ls + nas) 8π (Ls + nas)
(4)
where subscripts l and s represent long and short tube, respectively. For a test fluid η = ηl = ηs, it can be found from eqs 3, 4 as π (al 4ΔPl − as 4ΔPs) = 8qη[(L l − Ls) + n(al − as)] B
(5)
DOI: 10.1021/acs.jced.8b00036 J. Chem. Eng. Data XXXX, XXX, XXX−XXX
Journal of Chemical & Engineering Data
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Figure 3. Pressure distribution in tandem capillary tubes.
but (Ll − Ls) ≫ n(al − as); therefore, it is possible to be concluded as η=
π (al 4ΔPl − as 4ΔPs) 8q(L l − Ls)
the reference refrigerant R134a is used with >99.5% purity, supplied by Du Pont-Mitsui Fluorochemicals Co. Ltd. The fluids were analyzed in the experiment without further purification.
(6)
3. RESULTS AND DISCUSSION 3.1. Apparatus Reliability Test. Before the test fluid viscosity measurements, the reliability of the experimental apparatus should be checked.17,18 In this study, R134a was used as a reference fluid to confirm the reliability and stability of the measurements. The viscosity of R134a was measured at temperatures from 313 (39.85 °C) to 356 K (82.85 °C), and pressure of 1.70 to 4.16 MPa at liquid phase. The combined standard uncertainty of measurements of liquid R-134a is obtained better than 3.01%. The experimental data were compared with data calculated by using REFPROP v9.1 (in this version, Huber et al., 2003 experimental data were included),19 as shown in Figure 4 and listed in Table 3. The maximum and
This is the ultimate equation to determine viscosity of fluids by the tandem capillary tubes method. 2.2. Experimental Apparatus. The experimental apparatus to determine viscosity by the tandem capillary tubes method is shown in Figure 2, and the schematic diagram of pressure distribution in tandem capillary tubes can be observed from Figure 3. In this viscometer, the test fluids or refrigerants are circulated at a very small flow rate through two vessels, A and D, by a nonpulsation pump through a Coriolis (mini CORIFLOW M12) flowmeter. Inside viscometer vessel A, refrigerant flows in two different length capillaries of Pyrex tubes (B), which are in series connection; the inner diameters are 0.1269 and 0.1268 mm and the lengths are 99.85 and 50.16 mm for long and short tubes, respectively. An electric heater C and a thermostatic water bath M are used to maintain experimental conditions. A sight glass E connected to pressure vessel D is used to confirm the liquid level of test fluid placed in the thermostatic water bath. A helium cylinder is connected to pressure vessel D to get the desired pressure. A platinum resistance thermometer pt100 of diameter 1.6 mm is used to measure the temperature, and pressure transducers (model PG100 KU, KYOWA) were used to measure the system pressure. The pressure loss in each capillary was measured with a differential pressure gauge O (model PDU-A-50KP, KYOWA). The length and the inner diameter of the capillary tube were measured by reading microscope and gravimetric method using liquid mercury, respectively. 2.3. Sample Materials. The test fluid R-1336mzz(Z) was supplied by Chemours company (a multinational company headquartered in the USA). The specified purity is 99.95% mass fraction by supplier’s analysis, the CAS number is 692-499, and the sample information is listed in Table 2. Moreover,
Figure 4. Deviations between experimentally measured viscosity and REFPROP of liquid R-134a: ⊕, 313 K; ⊞, 333 K; □, at 356 K.
minimum deviations between the experimental and calculated data were −2.10 and −0.12%, respectively, and most of the measured data are within ±1.5% deviations. Therefore, the measured viscosity of R-134a shows a good agreement with calculated value of REFPROP. These results imply the confirmation of the reliability of measurement apparatus and technique. 3.2. Viscosity of R-1336mzz(Z). The viscosity of R1336mzz(Z) was measured by using the tandem capillary tubes method along a wide range of temperatures and pressures for
Table 2. Sample Information sample R-1336mzz(Z) R-134ab a
a
CASRN
purity (%)
manufacturer
692-49-9 811-97-2
99.95 99.50
Chemours company Du Pont-Mitsui Fluorochemicals Co. Ltd.
cis-1,1,1,4,4,4-Hexafluoro-2-butene. b1,1,1,2-Tetrafluoroethane. C
DOI: 10.1021/acs.jced.8b00036 J. Chem. Eng. Data XXXX, XXX, XXX−XXX
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Table 3. Experimental Viscosity η of R-134a at Liquid Phasea,b T (K)
P (MPa)
313.50 313.01 312.96 312.83 312.82 312.76 312.75 312.77 312.78 312.78 332.81 332.81 332.80 332.80 332.79 332.79 354.96 355.51 355.94
1.796 1.763 1.701 1.706 4.048 4.069 4.064 3.061 3.061 3.042 4.011 4.008 4.005 3.079 3.083 3.072 4.007 4.078 4.155
Table 4. Experimental Viscosity η of R-1336mzz(Z) at Liquid Phasea
ηexp (μPa·s) ηREFP (μPa·s)c 100(ηexp − ηREFP)/ηREFP 165.57 165.39 164.99 165.57 173.03 173.14 172.28 168.06 168.17 168.42 132.52 132.45 132.52 128.23 128.41 127.88 95.65 94.07 93.35
163.72 164.65 164.51 164.82 173.44 173.64 173.65 170.00 169.98 169.90 134.49 134.48 134.48 130.64 130.67 130.62 95.77 95.22 94.94
1.13 0.45 0.29 0.46 −0.24 −0.29 −0.79 −1.14 −1.07 −0.87 −1.47 −1.51 −1.46 −1.84 −1.73 −2.10 −0.12 −1.21 −1.67
a
Standard uncertainties u are u(T) = 0.027 K, u(P) = 0.003 MPa, and ur(η) = 0.0301. bηexp is the experimental viscosity and ηREFP is the REFPROP viscosity. cHuber et al.,19 2003
both liquid and vapor states in the present study. The measurement-covering regions for temperature and pressure are shown in Figure 5. In this Figure, the vapor liquid saturation
T (K)
P (MPa)
η (μPa·s)
T (K)
P (MPa)
η (μPa·s)
313.95 313.94 313.96 313.94 313.95 313.94 313.95 313.94 313.92 314.27 314.26 314.31 313.84 313.84 313.83 331.87 331.85 331.84 331.94 331.94 331.94 331.57 331.57 331.57 331.82 331.83 331.81 331.50 331.50 331.51 353.79 353.80 353.80 354.10 354.08 354.00
4.049 4.041 4.002 3.001 3.000 2.996 2.025 2.037 2.053 1.041 1.040 1.050 0.514 0.513 0.513 4.059 4.047 4.062 3.040 3.026 3.039 2.033 2.020 2.020 1.017 1.015 1.002 0.503 0.505 0.506 4.019 4.020 4.020 3.021 3.022 2.064
319.70 319.78 319.40 314.57 314.28 314.32 309.77 309.67 311.45 306.84 307.37 308.11 303.64 303.45 303.74 265.13 265.19 265.83 261.72 260.77 261.72 259.96 259.28 259.91 259.04 258.79 257.90 257.74 257.86 257.79 212.18 212.02 211.71 203.17 204.66 201.01
353.99 353.99 354.24 354.23 354.23 374.43 374.44 374.43 374.75 374.74 374.74 374.44 374.45 374.46 393.65 393.65 393.65 393.65 393.64 393.63 394.03 394.01 394.00 413.56 413.56 413.55 413.63 413.63 413.75 434.37 434.37 434.37 434.13 434.12 434.12
2.066 2.067 1.031 1.032 1.033 4.050 4.050 4.056 3.026 3.026 3.026 2.025 2.025 2.025 4.017 4.017 4.017 3.044 3.044 3.044 2.016 2.016 2.016 4.047 4.047 4.046 3.011 3.015 3.010 4.014 4.014 4.014 3.016 3.016 3.016
201.10 201.06 193.03 194.37 194.17 170.23 170.52 170.16 163.49 163.21 164.47 161.30 161.81 161.11 137.71 137.99 137.81 133.19 133.93 133.61 128.22 128.00 127.85 110.03 110.03 110.44 102.99 103.02 102.88 80.47 80.72 80.96 70.45 70.44 70.94
a
Standard uncertainties u are u(T) = 0.027 K, u(P) = 0.003 MPa, and ur(η) = 0.0304.
Table 5. Experimental Viscosity η of R-1336mzz(Z) at Vapor Phasea
Figure 5. Temperature and pressure ranges for the experimental points of R-1336mzz(Z): red ■, critical point.
line was drawn using the equation of state from Akasaka and Lemmon,15 and the critical temperature and pressure are 444.50 K (171.35 °C) and 2.895 MPa, respectively.3 The viscosity of liquid R-1336mzz(Z) was reported over the temperature range of 314 to 434 K up to 4.06 MPa, and those of vapor R-1336mzz(Z) are reported from 375 to 475 K up to 2.00 MPa. The experimental viscosity data for both liquid and vapor state are presented in Tables 4 and 5. The measurements’ combined standard uncertainties of R-1336mzz(Z) in both liquid and vapor phases are reported in Tables 4 and 5. The uncertainties of viscosity measurements were estimated following the law of propagation of uncertain-
T (K)
P (MPa)
η (μPa·s)
T (K)
P (MPa)
η (μPa·s)
374.87 374.88 394.16 394.19 414.21 413.99 414.24 414.29 414.29 434.28 434.28 434.23 434.23
0.492 0.492 0.499 0.499 0.503 0.503 1.014 1.033 1.033 1.012 1.011 0.503 0.502
13.00 13.05 13.48 13.43 13.61 13.78 14.49 14.34 14.44 14.43 14.51 13.84 13.88
454.24 454.27 454.34 454.34 454.57 454.58 474.84 474.83 474.85 474.82 473.27 474.69 474.67
0.506 0.506 1.003 1.003 2.031 2.030 2.004 2.004 1.000 0.999 0.509 0.500 0.500
14.29 14.30 15.47 15.68 16.28 16.33 16.61 16.90 15.79 15.87 21.01 15.19 15.20
a Standard uncertainties u are u(T) = 0.027 K, u(P) = 0.003 MPa, and ur(η) = 0.0321.
D
DOI: 10.1021/acs.jced.8b00036 J. Chem. Eng. Data XXXX, XXX, XXX−XXX
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ties.20−23 The errors due to pressure drop, diameter and length of capillary tube, flow rate, as well as measurement temperature and pressure are included to evaluate the uncertainty of measurements. The estimated uncertainties of flow rate show different values for liquid and vapor phases. In Figure 6, the experimental viscosity data are presented as a function of density, which was calculated from the measured
Figure 7. Viscosity of vapor R-1336mzz(Z) as a function of density: ○, 375 K; △, 394 K; ■, 414 K; ●, 434 K; half-filled triangle, 454 K; ◓, 475 K.
working fluid R-1336mzz(Z) at saturation state is a very important tool to design the energy system in the heat transfer area and simulation. The extrapolation method to get saturated viscosity of liquid R-1336mzz(Z) by identical temperature is understandable from Figure 8. In the case of vapor, the
Figure 6. Viscosity of liquid R-1336mzz(Z) as a function of density: ⊕, 314 K; ⊞, 332 K; □, 354 K; ○, 374 K; △, 394 K; ■, 414 K; ●, 434 K.
temperature and pressure with the equation of state of Akasaka and Lemmon.15 The viscosity of liquid R-1336mmz(Z) was measured in a temperature range from 314 to 434 K and for pressure 0.5 to 4.06 MPa. A typical change in viscosity is shown in the Figure with temperature and density. As the temperature increases, the viscosity of liquid R-1336mzz(Z) decreases. The combined standard uncertainty of measurements at the liquid phase was estimated to be
