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1.
V. A. Gruzdev S. G. Komarov S. V. Stankus 《International Journal of Thermophysics》2008,29(2):557-567
The density (300–363 K, up to 3.5 MPa) and speed of sound (293–373 K, 7.5–480 kPa) in gaseous R-404a have been studied by
an isochoric piezometer method and an ultrasonic interferometer, respectively. The pressures of the saturated vapor along
the dew line were measured from 298 to 330 K. The experimental uncertainties of the temperature, pressure, density, and speed-of-sound
measurements were estimated to be within ±20 mK, ±1.5 kPa, ±0.15%, and ±(0.1–0.2)%, respectively. On the basis of the obtained
data, the isobaric molar heat capacity of R-404a was calculated for the ideal-gas state. An eight-coefficient Benedict–Webb–Rubin
equation of state has been developed for the gaseous phase of R-404a. 相似文献
2.
The speed of sound and the density of the gaseous R-406A refrigerant within the temperature range 293–373 K and at the pressures from 0.05 MPa up to 0.6–2.3 MPa were investigated by means of an ultrasound interferometer and a constant volume piezometer. The measurement errors for the temperature, the pressure, and the speed of sound were ±20 mK, ±4 kPa, and ±(0.1–0.3)%, respectively. The approximation dependences of the investigated properties of the R-406A vapor are obtained and their errors are estimated. The obtained results are compared with the calculations using the REFPROP software. 相似文献
3.
The speed of sound in the R-415A refrigerant vapor and its density and pressure on the condensation line were measured by the ultrasonic interferometer and constant-volume piezometer methods within a range of temperatures from 293 to 373 K and pressures from 0.04 to 0.5–2.45 MPa. The temperature, pressure, density and speed of sound measurement errors were ±20 mK, ±4 kPa, and ±(0.1–0.2)%, respectively. The temperature dependence of the ideal-gas heat capacity was calculated on the basis of the obtained data. The obtained results were compared with the properties calculated by the REFPROP software. 相似文献
4.
V. A. Gruzdev R. A. Khairulin S. G. Komarov S. V. Stankus 《International Journal of Thermophysics》2008,29(2):546-556
The density of gaseous and liquid 1,1,1,2,3,3-hexafluoropropane (HFC-236ea) and the speed of sound in liquid HFC-236ea have
been studied by a γ-attenuation technique, an ultrasonic interferometer, and an isochoric piezometer method over the temperature range of 263–423 K
at pressures up to 4.05 MPa. The purity of the samples used throughout the measurements is 99.68 mol%. The pressures of the
saturated vapor were measured over the same temperature range. The experimental uncertainties of the temperature, pressure,
density, and speed-of-sound measurements were estimated to be within ±20 mK, ±1.5 kPa, ±(0.05–0.30)%, and ±(0.05–0.10)%, respectively. 相似文献
5.
We have measured the gas-phasePVT properties of 1,1,1,2,3,3,-hexafluoro-propane (R-236ea), which is considered to be a promising candidate for the replacement
of 1,2-dichlorotetrafluoroethane (R-114). The measurements have been performed with a Burnett apparatus over a temperature
range of 340 390 K and at pressures of 0.10–2.11 MPa. The experimental uncertainties of the measurements were estimated to
be within ±0.5 kPa in pressure. ±8 mK in temperature, and ±0.15% in density. A truncated virial equation of state was developed
to represent thePVT data and the second virial coefficients were also derived. The saturated vapor densities were also calculated by extrapolating
the gas-phase isotherms to the vapor pressures. The critical density estimated from the rectilinear diameter was compared
with the experimental value. The purity of the R-236ea sample used in the present measurements was 99.9 mol%.
Paper presented at the Fourth Asian Thermophysical Properties Conference, September 5–8, 1995, Tokyo, Japan. 相似文献
6.
A. P. Fröba H. Kremer A. Leipertz F. Flohr C. Meurer 《International Journal of Thermophysics》2007,28(2):449-480
This work presents a comprehensive experimental study of various thermophysical properties of an azeotropic refrigerant mixture
of 65 mass% R365mfc (1,1,1,3,3-pentafluorobutane) and 35 mass% Galden? HT 55 (perfluoropolyether). Light scattering from bulk fluids has been applied for measuring both the thermal diffusivity
and the speed of sound in the liquid and vapor phases under saturation conditions, between 293 K and the liquid–vapor critical
point at 450.7 K. Furthermore, the speed of sound has been measured for the superheated-vapor phase along nine isotherms,
between 393 and 523 K and up to a maximum pressure of about 2.5 MPa. For temperatures between 253 and 413 K, light scattering
by surface waves on a horizontal liquid–vapor interface has been used for simultaneous determination of the surface tension
and kinematic viscosity of the liquid phase. With light scattering techniques, uncertainties of less than ±2.0%, ±0.5%, ±1.5%,
and ±1.5% have been achieved for the thermal diffusivity, sound speed, kinematic viscosity, and surface tension, respectively.
In addition to vapor-pressure measurements between 304 and 448 K, the density was measured between 273 and 443 K using a vibrating-tube
method. Here, measurements have been performed in the compressed- and saturated-liquid phases with uncertainties of ±0.3%
and ±0.1%, respectively, as well as for the superheated vapor up to a maximum pressure of about 3 MPa with an uncertainty
between ±0.3% and ±3%. Critical-point parameters were derived by combining the data obtained by different techniques. 相似文献
7.
Thermal conductivity of the gaseous R-407C refrigerant was investigated by the coaxial cylinders method within the temperature
range of 303–425 K and the pressure range of 0.7–2.1 MPa. Approximating dependence of thermal conductivity on pressure and
temperature was obtained. Thermal conductivity on dew line and in ideal gas state was calculated. The comparison is performed
of the data obtained with those available in the literature. 相似文献
8.
H. Sunaga R. Tillner-Roth H. Sato K. Watanabe 《International Journal of Thermophysics》1998,19(6):1623-1635
We developed a fundamental equation of state for pentafluoroethane (R-125, CHF2CF3) which is represented in terms of a non-dimensional Helmholtz free energy. The equation has been established on the basis of selected measurements of the pressure-density-temperature relation, speed of sound, heat capacities, and saturation properties. Linear and non-linear regression analysis was employed to determine the functional form and the numerical parameters. The equation represents all the thermodynamic properties of R-125 in the liquid and gaseous phases for temperatures between the triple point and 470 K, and pressures up to 35 MPa. The uncertainties are estimated to be about ±0.05% or 0.1 kPa for the vapor pressure, ± 0.05 % for the liquid and vapor densities, about ± 1 % for the isobaric and isochoric heat capacities in the liquid, and ± 0.5 % or ± 0.02 % for the speed of sound in the liquid and vapor, respectively. 相似文献
9.
Ryo Akasaka 《International Journal of Thermophysics》2011,32(6):1125-1147
New fundamental equations of state explicit in the Helmholtz energy with a common functional form are presented for 2,3,3,3-tetrafluoropropene
(R-1234yf) and trans-1,3,3,3-tetrafluoropropene (R-1234ze(E)). The independent variables of the equations of state are the
temperature and density. The equations of state are based on reliable experimental data for the vapor pressure, density, heat
capacities, and speed of sound. The equation for R-1234yf covers temperatures between 240 K and 400 K for pressures up to
40 MPa with uncertainties of 0.1 % in liquid density, 0.3 % in vapor density, 2 % in liquid heat capacities, 0.05 % in the
vapor-phase speed of sound, and 0.1 % in vapor pressure. The equation for R-1234ze(E) is valid for temperatures from 240 K
to 420 K and for pressures up to 15 MPa with uncertainties of 0.1 % in liquid density, 0.2 % in vapor density, 3 % in liquid
heat capacities, 0.05 % in the vapor-phase speed of sound, and 0.1 % in vapor pressure. Both equations exhibit reasonable
behavior in extrapolated regions outside the range of the experimental data. 相似文献
10.
V. A. Belogol'skii S. S. Sekoyan L. M. Samorukova S. R. Stefanov V. I. Levtsov 《Measurement Techniques》1999,42(4):406-413
The sound velocity is measured in distilled water in the pressure range 0.1–60 MPa and in the temperature range 0–40°C. The
results are given in the form of tables and an equation derived by least-squares processing of the experimental data.
Translated from Izmeritel'naya Tekhnika, No. 4, pp. 66–69, April, 1999. 相似文献
11.
Models representing the thermodynamic behavior of the CO2–H2O mixture have been developed. The single-phase model is based upon the thermodynamic property mixture model proposed by Lemmon and Jacobsen. The model represents the single-phase vapor states over the temperature range of 323–1074 K, up to a pressure of 100 MPa over the entire composition range. The experimental data used to develop these formulations include pressure–density–temperature-composition, second virial coefficients, and excess enthalpy. A nonlinear regression algorithm was used to determine the various adjustable parameters of the model. The model can be used to compute density values of the mixture to within ±0.1%. Due to a lack of single-phase liquid data for the mixture, the Peng–Robinson equation of state (PREOS) was used to predict the vapor–liquid equilibrium (VLE) properties of the mixture. Comparisons of values computed from the Peng–Robinson VLE predictions using standard binary interaction parameters to experimental data are presented to verify the accuracy of this calculation. The VLE calculation is shown to be accurate to within ±3 K in temperature over a temperature range of 323–624 K up to 20 MPa. The accuracy from 20 to 100 MPa is ±3 K up to ±30 K in temperature, being worse for higher pressures. Bubble-point mole fractions can be determined within ±0.05 for CO2. 相似文献
12.
S. P. Andersson O. Andersson G. Bäckström 《International Journal of Thermophysics》1997,18(1):209-219
The thermal conductivity, λ of amorphous Teflon AF 1600 [poly(1,3-dioxole-4,5-difluoro-2,2-bis(trifluoromethyl)-co-tetrafluoroethylene)]
has been measured at pressures up to 2 GPa in the temperature range 93–392 K. At 295 K and atmospheric pressure, we obtained
λ=0.116, W·m−1·K−1. The bulk modulus was measured up to 1.0 GPa in the temperature range 150–296 K and the combined data yielded the following
values ofg=(∂ln λ ∂lnp)
r
:2.8±0.2 at 296 K, 3.0±0.2 at 258 K, 3.0±0.2 at 236 K. 3.4±0.2 at 200 K. and 3.4±0.2 at 150 K. 相似文献
13.
T. S. Khasanshin V. S. Samuilov A. P. Shchemelev 《Journal of Engineering Physics and Thermophysics》2008,81(4):760-765
This paper describes an improved experimental facility for measuring the speed of sound in liquids with an accuracy of up
to 0.1%. Measurements of the speed of sound in liquid n-hexane, n-octane, n-decane, and n-hexadecane at temperatures of 298–433
K and pressures of 0.1–100 MPa have been made. It has been shown that in the possible comparison range the obtained values
of the speed of sound are in good agreement with the literature data.
Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 81, No. 4, pp. 732–736, July–August, 2008. 相似文献
14.
L. E. A. Berlouis P. Honnor P. J. Hall S. Morris S. B. Dodd 《Journal of Materials Science》2006,41(19):6403-6408
The effect of additives Ti, Pd and Zr on the rate of hydrogen desorption from MgH2 is investigated using high-pressure differential scanning calorimetry. Van’t Hoff analysis as well as X-ray powder diffraction measurements confirm that no new intermetallic phases are formed in these systems but enhanced dehydriding kinetics are obtained in the presence of Pd and Zr. For the Mg–Zr composite, Zr precipitates are formed throughout the material on heating to 500 °C but these do not grow with further thermal cycling. The desorption rate for all the composites was found to increase with temperature as well as pressure difference between experimental and equilibrium pressures. A value of 114 ± 4 kJ mol−1 was obtained for the activation energy for dehydriding of the Mg–Ti–Pd composite. 相似文献
15.
On the basis of experimental data an analytical relationship is obtained between the thermal conductivity of liquids and sound
velocity in them for wide temperature and pressure ranges.
Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 70, No. 1, pp. 27–29, January–February, 1997. 相似文献
16.
We are developing an absorption air cooling system which can supply 2°C chilled water for air cooling by the usage of dilute
solutions of LiBr in water with an evaporating temperature of −6°C as a nonfreezing refrigerant. However, there are few published
data for the thermal properties of dilute LiBr water solutions (0 to 30%) below 10°C. In this paper, the freezing temperature
and the saturated vapor pressure are reported. The results clearly show the possibility of developing a new type of LiBr absorption
refrigerating machine to generate evaporating temperatures below 0°C. To obtain accurate data for the design of this new type
of absorption refrigerating machine, an apparatus has been developed to measure the thermal properties of dilute LiBr water
solutions below 10°C. The experimental arrangement consists of a cooling bath (340×240×190 mm) filled with fluorocarbon, a
glass measuring bottle (ϕ120×100 mm), and an absolute pressure gauge (0–1.3 kPa). The accuracy of the temperature, pressure,
and density are within ±0.1°C, 0.01 kPa, and ±0.005%, respectively.
Paper presented at the Fourth Asian Thermophysical Properties Conference, September 5–8, 1995, Tokyo, Japan. 相似文献
17.
The critical point of nickel and the phase diagram near the critical point are numerically evaluated using molecular dynamics
(MD) computations. Thermodynamic states on the phase diagram are calculated for a homogeneous material at equilibrium states.
Isothermal lines on p–v diagrams are constructed at temperatures below and above the critical temperature, and the liquid-gas coexistence lines and
regimes are obtained. The critical point of nickel is obtained as T
c
= 9460± 20 K, ρ
c
= 2560± 100 kg· m−3, and p
c
= 1.08± 0.01 GPa. The method used in this work can be used to estimate thermodynamic properties of other materials at high
temperature/pressure. 相似文献
18.
A newly designed experimental apparatus has been used to measure the speed of sound u in high-purity water on nine isotherms between 274 and 394 K and at pressures up to 90 MPa. The measurement technique is
based on a traditional double-reflector pulse-echo method with a single piezoceramic transducer placed at unequal distances
from two stainless steel reflectors. The transit times of an acoustic pulse are measured at a high sampling rate by a digital
oscilloscope. The distances between the transducer and the reflectors were obtained at ambient temperature and pressure by
direct measurements with a coordinate measuring machine. The speeds of sound are subject to an overall estimated uncertainty
of 0.05 %. The acoustic data were combined with available values of density ρ and isobaric heat capacity cp along one isobar at atmospheric pressure to calculate the same quantities over the whole temperature and pressure range by
means of a numerical integration technique. These results were compared with those calculated from the IAPWS-95 formulation
with corresponding relative deviations which are within 0.1%.
Paper presented at the Fifteenth Symposium on Thermophysical Properties, June 22–27, 2003, Boulder, Colorado, U.S.A. 相似文献
19.
T. S. Khasanshin V. S. Samuilov A. P. Shchemelev F. M. Mosbach 《Journal of Engineering Physics and Thermophysics》2010,83(5):1043-1053
By the method of direct measurement of the pulse-passage time, the velocity of sound in a binary liquid mixture n-dodecane+n-hexadecane has been investigated in the temperature range 298–433 K and in the pressure range 0.1–100.1 MPa. The maximum
measurement error is 0.1%. Experimental data on the velocity of sound for the investigated mixture have been obtained for
the first time. On the basis of the data on the velocity of sound, we have determined the density, the isobaric expansion
coefficient, the isobaric and isochoric heat capacities, and the isothermal compressibility coefficient of a mixture of three
compositions in the 298–433 K temperature range and in the 0.1–100.1 MPa range of pressures. The coefficients of the Tate
equations in the above range of parameters have been calculated. A table of thermodynamic properties of the mixture is presented. 相似文献
20.
Andreas Paul Fröba Cristina Botero Heiko Kremer Alfred Leipertz 《International Journal of Thermophysics》2007,28(3):743-757
Dynamic light scattering (DLS) has been used for the measurement of several thermophysical properties of a quaternary refrigerant
mixture R-125/143a/32/134a in its liquid phase under saturation conditions. The thermal diffusivity and sound speed have been
obtained by light scattering from bulk fluids over a temperature range from about 293 K up to the liquid–vapor critical point.
By applying the method of DLS to a liquid–vapor interface, also called surface light scattering (SLS), the saturated liquid
kinematic viscosity and surface tension can be determined simultaneously. These properties have been measured from about 243
to 343 K. The results are discussed in comparison with literature data and with a simple prediction method based on the mass-weighted
properties of the pure components, expressed as functions of the reduced temperature. Once again, the simple prediction method
was shown to be applicable for the calculation of different transport and other thermophysical properties of multicomponent
refrigerant mixtures and this with sufficiently high accuracy for technical practice. Moreover, the input data for the simple
prediction scheme can be reduced without loss of accuracy by treating binary or ternary mixtures as a subset of the multicomponent
mixture. 相似文献