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Gas flow through rough microchannels in the transition flow regime.
Zilong Deng1, Yongping Chen1, Chenxi Shao1
1Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing, Jiangsu 210096, People's Republic of China.
Physical Review. E
|February 13, 2016
Summary
Surface roughness significantly impacts rarefied gas flow in microchannels, especially in the transition regime. Flow behavior is more sensitive to roughness height than fractal dimension as the Knudsen number increases.
Area of Science:
- Fluid dynamics
- Microfluidics
- Computational physics
Background:
- Microchannel gas flow is crucial for micro-electromechanical systems (MEMS).
- Rarefaction and surface roughness effects are significant in microscale flows.
- Understanding transition flow regime behavior is essential for device design.
Purpose of the Study:
- To investigate rarefied gas flow in microchannels with fractal roughness.
- To elucidate coupled effects of roughness and rarefaction in the transition flow regime.
- To analyze the influence of roughness height and fractal dimension on microscale gas flow.
Main Methods:
- Development of a multiple-relaxation-time lattice Boltzmann model.
- Simulation of Couette flow in microchannels with fractal roughness.
- Analysis of gas flow behavior across varying Knudsen numbers.
Main Results:
- Surface roughness effects intensify with increasing Knudsen number.
- Transition flow regime is more sensitive to roughness height than slip flow regime.
- Fractal dimension has a lesser impact on rarefied gas flow compared to roughness height.
Conclusions:
- Surface roughness and rarefaction critically influence microchannel gas flow.
- Roughness height is a dominant factor in the transition flow regime.
- The study provides insights into designing microfluidic devices operating in rarefied conditions.
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