scholarly journals Simulation of a two-dimensional binary gas mixture outflow into vacuum through a thin slit on the basis of direct solution of the Boltzmann kinetic equation

2021 ◽  
Vol 2056 (1) ◽  
pp. 012007
Author(s):  
S S Sitnikov ◽  
F G Tcheremissine ◽  
T A Sazykina
Keyword(s):  
Kinetic Equation ◽  
Boltzmann Kinetic Equation ◽  
Gas Mixture ◽  
Two Dimensional ◽  
Direct Solution ◽  
Steady State Regime ◽  
Collision Integrals ◽  
Flow Formation ◽  
Binary Gas Mixture ◽  
State Regime

Abstract Two-dimensional binary gas mixture outflow from a vessel into vacuum through a thin slit is studied on the basis of direct solution of the Boltzmann kinetic equation. For evaluation of collision integrals in the Boltzmann equation a conservative projection method is used. Numerical simulation of a two-dimensional argon-neon gas mixture outflow from a vessel into vacuum was performed. Graphs of mixture components flow rate dependence on time during the flow formation, as well as fields of molecular density and temperature for steady-state regime, were obtained.

THE NUMERICAL SOLUTION OF THE BOLTZMANN KINETIC EQUATION FOR GRANULAR GASES

2019 ◽  
pp. 25-30
Author(s):  
I. Gapyak
Keyword(s):  
Cauchy Problem ◽  
Kinetic Equation ◽  
Numerical Solution ◽  
Dimensional Space ◽  
Boltzmann Kinetic Equation ◽  
Granular Gases ◽  
Two Dimensional ◽  
System Of Particles ◽  
The Cauchy Problem

For a system of particles with a dissipative interaction we consider the Boltzmann type kinetic equation for granular gases. A numerical solution of the Cauchy problem for the Boltzmann type kinetic equation is constructed in two dimensional space and its stability is investigated.

scholarly journals INTEGRATION OF THE NUMERICAL SOLUTION MODULE OF THE KINETIC EQUATION INTO THE CFD PACKAGE FOR THE VOLUME CONDENSATION PROBLEM OF THE VAPOR-GAS MIXTURE FLOW THROUGH A NOZZLE

2021 ◽  
Vol 48 (1) ◽  
pp. 65-75
Author(s):  
A. A. Sidorov ◽  
A. K. Yastrebov
Keyword(s):  
Distribution Function ◽  
Kinetic Equation ◽  
Numerical Solution ◽  
Droplet Size Distribution ◽  
Size Distribution Function ◽  
Gas Mixture ◽  
Two Dimensional ◽  
Mixture Flow ◽  
Volume Condensation ◽  
Flow Through

Objective. Integrating the numerical solution module of the kinetic equation for the droplet size distribution function in a CFD package. Application of the module to volumetric condensation at the supersonic flow of a vapor-gas  mixture through a nozzle in a two-dimensional formulation, comparison of  the results with experimental data of third-party authors.Methods. In this  paper, the problem of volume condensation in the supersonic flow of a vapor-gas mixture through a nozzle is solved by finite element methods in a two-dimensional formulation using user-defined functions.Results. A module for the numerical solution of the kinetic equation for the droplet size distribution function is presented as a user-defined function integrated into the calculated CFD package.Conclusion. The module application to volumetric condensation for a vapor-gas mixture flow through the nozzle gave a qualitative agreement in all areas and a quantitative agreement in the area of intense condensation with  measurement data. The distributions of temperatures, pressures, and  the degree of supersaturation are presented both along the central axis and  on the plane bounded by the contour of the computational domain. It is shown that the module does not depend on the solver type (stationary or non-stationary).

New single vortex generation method for flame/vortex interaction using flow behind a rotating cylinder

2021 ◽  
Author(s):  
Soufyane Hazel ◽  
Yong Huang ◽  
Mokhtar Ait Amirat
Keyword(s):  
Rotation Rate ◽  
Rotating Cylinder ◽  
Two Dimensional ◽  
Vortex Interaction ◽  
Steady State Regime ◽  
Single Vortex ◽  
Rotation Rates ◽  
State Regime ◽  
Feeding Process ◽  
Final Rotation

Abstract This paper investigates a new experimental method to generate a single two-dimensional translated vortex for flame/vortex interaction studies. A rotating cylinder is immersed in a uniform flow and, its rotating speed is impulsively reduced. This sudden action triggers the generation of a single vortex when both the initial and the final rotation speeds are in the range of a steady-state regime. Flow visualization allows confirming the applicability of this method, while a complementary two-dimensional numerical simulation is conducted to understand the vortex formation process. A vorticity layer is detached from the cylinder, initiating a feeding process and gradual growth of a single leading vortex. The feeding process is saturated at a specific distance from the cylinder and, vortex separation from the vorticity layer is observed. At the final stage of the formation process, the generated vortex is advected away and, a steady-state regime is again established behind the cylinder. The vortex characteristics appear to be related to the normalized reduction in the rotation rate ∆α, defined as the initial and final rotation rates difference normalized by the initial rotation rate. Several combinations of initial and final rotation rates corresponding to different normalized reductions are investigated experimentally and numerically. The results allow understanding the effect of this parameter; a higher normalized reduction generates a stronger, more rapidly growing vortex. However, its trajectory is related to the wake deviation corresponding to the final rotation rate.

scholarly journals Influence of Casting Solvents on CO2/CH4 Separation Using Polysulfone Membranes

Membranes ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 286
Author(s):  
Roba M. Almuhtaseb ◽  
Ahmed Awadallah-F ◽  
Shaheen A. Al-Muhtaseb ◽  
Majeda Khraisheh
Keyword(s):  
High Efficiency ◽  
In Situ Synthesis ◽  
Separation Process ◽  
Polymeric Membranes ◽  
Gas Mixture ◽  
Manufacturing Cost ◽  
Binary Gas Mixture ◽  
Maximum Permeability ◽  
Polysulfone Membranes

Polysulfone membranes exhibit resistance to high temperature with low manufacturing cost and high efficiency in the separation process. The composition of gases is an important step that estimates the efficiency of separation in membranes. As membrane types are currently becoming in demand for CO2/CH4 segregation, polysulfone will be an advantageous alternative to have in further studies. Therefore, research is undertaken in this study to evaluate two solvents: chloroform (CF) and tetrahydrofuran (THF). These solvents are tested for casting polymeric membranes from polysulfone (PSF) to separate every single component from a binary gas mixture of CO2/CH4. In addition, the effect of gas pressure was conducted from 1 to 10 bar on the behavior of the permeability and selectivity. The results refer to the fact that the maximum permeability of CO2 and CH4 for THF is 62.32 and 2.06 barrer at 1 and 2 bars, respectively. Further, the maximum permeability of CF is 57.59 and 2.12 barrer at 1 and 2 bars, respectively. The outcome selectivity values are 48 and 36 for THF and CF at 1 bar, accordingly. Furthermore, the study declares that with the increase in pressure, the permeability and selectivity values drop for CF and THF. The performance for polysulfone (PSF) membrane that is manufactured with THF is superior to that of CF relative to the Robeson upper bound. Therefore, through the results, it can be deduced that the solvent during in-situ synthesis has a significant influence on the gas separation of a binary mixture of CO2/CH4.

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