scholarly journals Particle simulation of micro-scale gas flows

2001 ◽  
Author(s):  
Iain Boyd ◽  
Quanhua Sun
Keyword(s):  
Particle Simulation ◽  
Gas Flows ◽  
Micro Scale

scholarly journals Development of an Efficient Particle Approach for Micro-Scale Gas Flow Simulations

2009 ◽  
Author(s):  
Quanhua Sun ◽  
Feng Li ◽  
Jing Fan ◽  
Chunpei Cai
Keyword(s):  
Cell Size ◽  
Gas Flow ◽  
Rarefied Gas ◽  
Direct Simulation Monte Carlo ◽  
Gas Flows ◽  
Dsmc Method ◽  
Low Speed ◽  
Micro Scale ◽  
Information Preservation ◽  
Cfd Method

The micro-scale gas flows are usually low-speed flows and exhibit rarefied gas effects. It is challenging to simulate these flows because traditional CFD method is unable to capture the rarefied gas effects and the direct simulation Monte Carlo (DSMC) method is very inefficient for low-speed flows. In this study we combine two techniques to improve the efficiency of the DSMC method. The information preservation technique is used to reduce the statistical noise and the cell-size relaxed technique is employed to increase the effective cell size. The new cell-size relaxed IP method is found capable of simulating micro-scale gas flows as shown by the 2D lid-driven cavity flows.

Influence of Surface Roughness on Micro-Scale Rarefied Gas Flows

2008 ◽  
Author(s):  
O. A. Aksenova ◽  
L. A. Khalidov ◽  
Takashi Abe
Keyword(s):  
Surface Roughness ◽  
Rarefied Gas ◽  
Gas Flows ◽  
Micro Scale ◽  
Rarefied Gas Flows

Study on the micro-scale effect in the micro–nano organic pores of a shale reservoir

2017 ◽  
Vol 232 (3) ◽  
pp. 491-501
Author(s):  
Zisen Wu ◽  
Pingchuan Dong ◽  
Gang Lei ◽  
Nai Cao ◽  
Yudan Li ◽  
...  
Keyword(s):  
Surface Diffusion ◽  
Scale Effect ◽  
Mass Flow ◽  
Lattice Boltzmann Model ◽  
Gas Flows ◽  
Adsorption Effect ◽  
Free Gas ◽  
Micro Scale ◽  
Slippage Effect ◽  
Organic Pores

The micro-scale effect occurs because of the gas flows in shale reservoirs containing small organic pores. In this study, based on a lattice Boltzmann model incorporating the bounce-back and specular-reflection boundary conditions, the gas flow through two parallel plates driven by differential pressures is simulated, which in turn verifies the model. Considering the effects of the slippage, surface diffusion, and adsorption, the gas flow in the organic channels is simulated based on the proposed lattice Boltzmann model. It is shown that the micro-scale effect is significant in the gas flows in the micro-scale channels. The compression effect leads to a nonlinear distribution of pressures along the centreline of the flow channels, and the nonlinearity increases with an increase in the pressure difference between the two sides of the flow channel. In case of gas flows in organic pores, the adsorption effect decreases the free-gas velocities, and with a decrease in pore sizes, the average free-gas velocity is reduced owing to the increased adsorption effect. The slippage effect and surface diffusion have a significant impact on the free-gas velocity of the mass flow. Compared to the slippage effect, surface diffusion contributes more to the mass flow of gas in organic pores. An increase in the Knudsen number intensifies the slippage effect and surface diffusion and enhances the mass flow.

Simulation of Rarefied Gas Flows in MEMS/NEMS Using a Molecular Method

2009 ◽  
Author(s):  
Hadi Ghezel Sofloo ◽  
Reza Ebrahimi ◽  
Alireza Shams
Keyword(s):  
Rarefied Gas ◽  
Molecular Model ◽  
Direct Simulation Monte Carlo ◽  
Boltzmann Distribution ◽  
Gas Flows ◽  
Air Bearing ◽  
Molecular Collision ◽  
Micro Scale ◽  
Rarefied Gas Flows ◽  
Slider Air Bearing

In this work, the development of a two-dimensional Direct Simulation Monte Carlo (DSMC) Program for pressure boundaries using unstructured cells and its applications to typical micro-scale gas flows are described. For the molecular collision kinetics, variable hard sphere molecular model and no time counter collision sampling scheme have been used. Applications to micro-scale gas flows include micro-nozzel, nano channel and slider air bearing. The aim is to further test the treatment of pressure boundaries. For slider air bearing gas flows of the computer hard drive, the simulated gas pressures, at different rotating speeds, have a very good agreement with previous studies. The applicability of the treatment of pressure boundaries using the equilibrium Maxwell-Boltzmann distribution function was discussed in terms of the magnitude of the local Knudsen number at the pressure boundary for micro-nozzles and slider air bearing applications.

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