scholarly journals Investigation of applicability of Peng–Robinson and GERG-2008 equations of state of real gas for calculating properties of Freons for refrigeration machines and compressors

2021 ◽  
Vol 5 (1) ◽  
pp. 34-43
Author(s):  
M. I. Sokolov ◽  
◽  
Yu. V. Kozhukhov ◽  
Keyword(s):  
Experimental Data ◽  
Vapor Pressure ◽  
Mathematical Modelling ◽  
Equations Of State ◽  
Saturated Vapor Pressure ◽  
Saturated Vapor ◽  
Saturation Pressure ◽  
State Equations ◽  
Real Gas ◽  
Enthalpy And Entropy

A study of real gas state equations Peng–Robinson and GERG-2008 with respect to calculation of Freons R404A, R408A and R410A has been carried out. Four Freon parameters are calculated during the study: saturated vapor pressure at the saturation line at some Freon temperature, Freon density at saturation pressure and some temperature, enthalpy and entropy at the same pressures and temperature. The data obtained from the calculation of Freon by the above equations are compared with the experimental data for each of the above Freons. As a result of this work, data have been obtained to evaluate the accuracy of the Peng–Robinson and GERG-2008 equations of state for each of the three CFCs, to evaluate the effectiveness of these equations, and to provide recommendations for the calculation and application of these equations in the design and mathematical modelling of refrigeration machines

Influence of Nano-Refrigeration-Oil on Saturated Vapor Pressure of R22

2011 ◽  
Vol 694 ◽  
pp. 309-314 ◽  
Author(s):  
Jiang Feng Lou ◽  
Rui Xiang Wang ◽  
Min Zhang
Keyword(s):  
Experimental Data ◽  
Vapor Pressure ◽  
Mass Fraction ◽  
Saturated Vapor Pressure ◽  
Saturated Vapor ◽  
Experimental Results ◽  
Vapor Pressures ◽  
Temperature Range ◽  
Mass Fractions

The saturated vapor pressures of R22 uniformly mixed with refrigeration oil and nano- refrigeration-oil were measured experimentally at a temperature range from 263 to 333K and mass fractions from 1 to 5%. The experimental results showed that the saturated vapor pressure of R22/KT56 mixture was lower than that of pure R22; the pressure deviation between them increased with a raising mass fraction of refrigeration oil and temperature. After adding nano-NiFe2O4 and nano-fullerene into KT56, the pressure deviation increased at the same mass fraction and temperature. A saturated vapor pressure correlation for R22 and refrigeration oil/nano-refrigeration-oil mixture was proposed, and the calculated values agreed with the experimental data within the deviation of ± 0.77%.

Dependence of the Equation of State in Surface Tension Prediction by the Theory of Capillarity

2009 ◽  
Author(s):  
Aaron P. Wemhoff
Keyword(s):  
Experimental Data ◽  
Surface Tension ◽  
Vapor Pressure ◽  
Interfacial Tension ◽  
Saturated Vapor ◽  
Saturation Pressure ◽  
Liquid Density ◽  
Fluid Models ◽  
Vapor Density ◽  
Surface Tension Data

The theory of capillarity was originally developed by J. D. van der Waals to provide a means of predicting interfacial (surface) tension data using saturation pressure and liquid-vapor density data. This theory was recently extended to the Redlich-Kwong, Soave-Redlich-Kwong, and Peng-Robinson fluid models. The latter two equations of state are more advanced than the Redlich-Kwong model in that they use an acentric factor to predict saturated vapor pressure values more in agreement with experimental data. However, the agreement in the predicted interfacial tension values is worse for the latter two models compared to the Redlich-Kwong model. This study features a sensitivity analysis to show that the predicted interfacial tension values are more sensitive to vapor density than liquid density and vapor pressure, and that increasing the vapor density reduces the corresponding predicted interfacial tension value. Furthermore, all three fluid models tend to overpredict interfacial tension when experimental data are applied in their predictive equations. This study finds that the reason why the simpler Redlich-Kwong model predicts better interfacial tension values than the two advanced models is because the former overpredicts vapor density moreso than the two advanced cubic fluid models, and this in turn reduces the prediction of interfacial tension to make its value more comparable to experimental data.

A PROPERTY OF THE SATURATED VAPOR PRESSURE: RESULTS FROM EQUATIONS OF STATE

2009 ◽  
Vol 23 (26) ◽  
pp. 3091-3096 ◽  
Author(s):  
JIANXIANG TIAN ◽  
HUA JIANG ◽  
YI XU
Keyword(s):  
Critical Temperature ◽  
Equation Of State ◽  
Vapor Pressure ◽  
Hard Sphere ◽  
Critical Pressure ◽  
Equations Of State ◽  
Saturated Vapor Pressure ◽  
Saturated Vapor ◽  
Maximum Point ◽  
Critical Amplitudes

Experimentally, a maximum point in the curve of the saturated property ψ=(1-Tr)Pr versus the saturated temperature was postulated (High Temp.-High Press.26 (1994) 427). Here, Tr is the saturated temperature reduced by the critical temperature and Pr is the saturated pressure reduced by the critical pressure. Later, this behavior was applied to assure the saturated vapor pressure critical amplitudes (Appl. Phys. Lett.90 (2007) 141905). In this paper, we indicate that theory of equation of state (EOS) can predict this maximum point. The EOSs we study are the combinations of the hard sphere repulsions and some normally used attractions such as the Redlich–Kwong attraction. We find the EOSs with Redlich–Kwong attractive terms give out the results in the experimental range.

Properties of Refrigerants from Cubic Equations of State

2008 ◽  
Vol 59 (5) ◽  
Author(s):  
Viorel Feroiu ◽  
Dan Geana ◽  
Catinca Secuianu
Keyword(s):  
Experimental Data ◽  
Vapor Pressure ◽  
Equations Of State ◽  
Ternary Mixtures ◽  
Volumetric Properties ◽  
Mixing Rules ◽  
Saturation Curve ◽  
Equilibrium Thermodynamic ◽  
Liquid Equilibrium ◽  
Binary And Ternary Mixtures

Vapour � liquid equilibrium, thermodynamic and volumetric properties were predicted for three pure hydrofluorocarbons: difluoromethane (R32), pentafluoroethane (R125) and 1,1,1,2 � tetrafluoroethane (R134a) as well as for binary and ternary mixtures of these refrigerants. Three cubic equations of state GEOS3C, SRK (Soave � Redlich � Kwong) and PR (Peng � Robinson) were used. A wide comparison with literature experimental data was made. For the refrigerant mixtures, classical van der Waals mixing rules without interaction parameters were used. The GEOS3C equation, with three parameters estimated by matching several points on the saturation curve (vapor pressure and corresponding liquid volumes), compares favorably to other equations in literature, being simple enough for applications.

scholarly journals Effects of nanoparticles on hydraulic cavitation

2018 ◽  
Vol 240 ◽  
pp. 03004
Author(s):  
Min-rui Chen ◽  
Jin-yuan Qian ◽  
Zan Wu ◽  
Chen Yang ◽  
Zhi-jiang Jin ◽  
...  
Keyword(s):  
Vapor Pressure ◽  
Saturated Vapor Pressure ◽  
Saturated Vapor ◽  
Geometric Model ◽  
Pressure Ratio ◽  
Perforated Plate ◽  
Significant Parameter ◽  
Operation Conditions ◽  
Small Bubbles ◽  
Crucial Condition

When liquids flowing through a throttling element, such as a perforated plate, the velocity increases and the pressure decreases. If the pressure is below the saturated vapor pressure, the liquid will vaporize into small bubbles, which is called hydraulic cavitation. In fact, vaporization nucleus is another crucial condition for vaporizing. The nanoparticles contained in the nanofluids play a significant role in vaporization of liquids. In this paper, the effects of the nanoparticles on hydraulic cavitation are investigated. Firstly, a geometric model of a pipe channel equipped with a perforated plate is established. Then with different nanoparticle volume fractions and diameters, the nanofluids flowing through the channel is numerically simulated based on a validated numerical method. The operation conditions, such as the temperature and the pressure ratio of inlet to outlet, are the considered variables. As a significant parameter, cavitation numbers under different operation conditions are achieved to investigate the effects of nanoparticles on hydraulic cavitation. Meanwhile, the contours are extracted to research the distribution of bubbles for further investigation. This study is of interests for researchers working on hydraulic cavitation or nanofluids.

Porous Hydroxyapatite with Tailored Crystal Surface Prepared by Hydrothermal Method

2005 ◽  
Vol 284-286 ◽  
pp. 353-356 ◽  
Author(s):  
Koji Ioku ◽  
Giichiro Kawachi ◽  
Nakamichi Yamasaki ◽  
Hirotaka Fujimori ◽  
Seishi Goto
Keyword(s):  
Aspect Ratio ◽  
Vapor Pressure ◽  
Hydrothermal Method ◽  
Saturated Vapor Pressure ◽  
Crystal Surface ◽  
Saturated Vapor ◽  
Pure Water ◽  
Porous Hydroxyapatite ◽  
Exposure Method ◽  
The Mean

Porous plates of hydroxyapatite (Ca10(PO4)6(OH)2; HA) with about 0.5 to 5 mm in thickness and porous HA granules of about 40 µm to 1 mm in size with tailored crystal surface were prepared by the hydrothermal vapor exposure method at the temperatures above 105 °C under saturated vapor pressure of pure water. Porous HA plates with about 75 % porosity prepared at 120 °C were composed of rod-shaped crystals of about 20 µm in length. Porous HA granules prepared at 160 °C were also composed of rod-shaped crystals of about 20 µm in length with the mean aspect ratio of 30. These crystals were elongated along the c-axis. Rod-shaped HA crystals were locked together to make micro-pores of about 0.1 to 0.5 µm in size. Both of materials were nonstoichiometric HA with calcium deficient composition. These materials must have the advantage of adsorptive activity, because they had large specific crystal surface and much micro-pores.

scholarly journals Application of a Micro-Flow Regulating Valve in Saturated Vapor Pressure Measurements

Daxue Huaxue ◽  
2021 ◽  
Vol 0 (0) ◽  
pp. 2107062-0
Author(s):  
Shuai Zhang ◽  
Jian Zhang ◽  
Shaowei Bian ◽  
Yaping Zhao ◽  
Li Shen ◽  
...  
Keyword(s):  
Vapor Pressure ◽  
Saturated Vapor Pressure ◽  
Saturated Vapor ◽  
Pressure Measurements ◽  
Micro Flow ◽  
Vapor Pressure Measurements
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