scholarly journals Experimental study of R-32/R-125 (75/25 wt.%) thermal conductivity in the vapor phase

2021 ◽  
Vol 2119 (1) ◽  
pp. 012144
Author(s):  
E P Raschektaeva ◽  
S V Stankus
Keyword(s):  
Thermal Conductivity ◽  
Experimental Study ◽  
Binary Mixture ◽  
Vapor Phase ◽  
Pressure Range ◽  
Ideal Gas ◽  
Coaxial Cylinders ◽  
Temperature Range ◽  
Dew Line ◽  
The Ideal

Abstract The article presents the investigation of the thermal conductivity of binary mixture R-32/R-125 (75/25) in the gas state. Measurements were taken with a coaxial cylinders method in the temperature range of 305-426 K and the pressure range of 0.1-1.8 MPa. The dependence of thermal conductivity on pressure and temperature was discussed. The equations for thermal conductivity on the dew line and in the ideal gas state were obtained.

scholarly journals Inverse Chapman–Enskog Derivation of the Thermohydrodynamic Lattice-BGK Model for the Ideal Gas

1998 ◽  
Vol 09 (08) ◽  
pp. 1231-1245 ◽  
Author(s):  
B. M. Boghosian ◽  
P. V. Coveney
Keyword(s):  
Thermal Conductivity ◽  
Distribution Function ◽  
Relaxation Time ◽  
Equilibrium Distribution ◽  
Transport Coefficients ◽  
Ideal Gas ◽  
Equilibrium Distribution Function ◽  
Bgk Model ◽  
Constant Relaxation Time ◽  
The Ideal

A thermohydrodynamic lattice-BGK model for the ideal gas was derived by Alexander et al. in 1993, and generalized by McNamara et al. in the same year. In these works, particular forms for the equilibrium distribution function and the transport coefficients were posited and shown to work, thereby establishing the sufficiency of the model. In this paper, we rederive the model from a minimal set of assumptions, and thereby show that the forms assumed for the shear and bulk viscosities are also necessary, but that the form assumed for the thermal conductivity is not. We derive the most general form allowable for the thermal conductivity, and the concomitant generalization of the equilibrium distribution. In this way, we show that it is possible to achieve variable (albeit density-dependent) Prandtl number even within a single-relaxation-time lattice-BGK model. We accomplish this by demanding analyticity of the third moments and traces of the fourth moments of the equilibrium distribution function. The method of derivation demonstrates that certain undesirable features of the model — such as the unphysical dependence of the viscosity coefficients on temperature — cannot be corrected within the scope of lattice-BGK models with constant relaxation time.

Experimental study of thermal conductivity of refrigerant R-409A in vapor phase

2011 ◽  
Vol 18 (4) ◽  
pp. 661-664 ◽  
Author(s):  
O. I. Verba ◽  
E. P. Raschektaeva ◽  
S. V. Stankus
Keyword(s):  
Thermal Conductivity ◽  
Experimental Study ◽  
Vapor Phase

Experimental study of thermal conductivity of the R-406A refrigerant in the vapor phase

2014 ◽  
Vol 52 (1) ◽  
pp. 135-137 ◽  
Author(s):  
O. I. Verba ◽  
E. P. Raschektaeva ◽  
S. V. Stankus
Keyword(s):  
Thermal Conductivity ◽  
Experimental Study ◽  
Vapor Phase

A comparative study of thermodynamic models to describe the VLE of the ternary electrolytic mixture H2O–NH3–CO2

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Licianne P. S. Rosa ◽  
Natan Cruz ◽  
Glória M. N. Costa ◽  
Karen V. Pontes
Keyword(s):  
Experimental Data ◽  
Liquid Phase ◽  
Equation Of State ◽  
Activity Coefficient ◽  
Vapor Phase ◽  
Large Scale ◽  
Optimization Problems ◽  
Ideal Gas ◽  
Simultaneous Optimization ◽  
The Ideal

Abstract This study aims to ascertain the influence of the activity coefficient model and equation of state for predicting the vapor–liquid equilibrium (VLE) of the multi-electrolytic system H2O–NH3–CO2. The non-idealities of the liquid phase are described by the eUNIQUAC and eNRTL models. The vapor phase is modeled with the Nakamura equation, which is compared with the ideal gas assumption. The models are validated with experimental data from literature on total pressure and ammonia partial pressure. Results show that the models UNIQUAC and NRTL without dissociation can only reproduce the experimental conditions in the absence of CO2. When the electrolytic term is considered, the eUNIQUAC model is able to reproduce the experimental data with greater accuracy than the eNRTL. The equation of state which describes the vapor phase plays no major role in the accuracy of the VLE prediction in the operational conditions evaluated here. Indeed, the accuracy relies on the activity coefficient, therefore the ideal gas equation can be considered if the non-idealities of the liquid phase are described by a well-tuned model. These findings could be useful for equipment design, flowsheet simulations and large-scale simultaneous optimization problems.

Experimental Study of Thermal Conductivity of R-125/R-134A (39/61) Mixture in Vapor Phase

2020 ◽  
Vol 29 (2) ◽  
pp. 205-208
Author(s):  
E. P. Raschektaeva ◽  
S. V. Stankus ◽  
O. I. Verba
Keyword(s):  
Thermal Conductivity ◽  
Experimental Study ◽  
Vapor Phase ◽  
R 134A
Sign in / Sign up

Export Citation Format

Share Document