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Combined Forced and Thermocreep Convection through a Long Horizontal Microchannel.
1Department of Mechanical Engineering, Chung Yuan Christian University, Taoyuan 32023, Taiwan. hcweng@cycu.edu.tw.
Micromachines
|November 9, 2018
Summary
Thermal creep significantly impacts microchannel mixed convection, affecting velocity, flow rate, and heat transfer. This effect is more pronounced with lower pressure drops or higher Knudsen numbers.
Area of Science:
- Fluid dynamics
- Heat transfer
- Microscale transport phenomena
Background:
- Microchannels are crucial in various applications, requiring understanding of fluid flow and heat transfer.
- Thermal creep, a rarefaction effect, influences gas behavior near surfaces at microscale.
- Mixed convection involves both buoyancy and forced flow, common in microscale heat exchangers.
Purpose of the Study:
- To investigate the influence of thermal creep on mixed convection in horizontal parallel-plate microchannels.
- To derive analytical solutions for thermal-flow fields considering thermal creep and Maxwell boundary conditions.
- To analyze the impact of thermal creep on key flow and heat transfer characteristics.
Main Methods:
- Analytical solution derivation for fully developed thermal-flow fields.
- Application of Maxwell boundary conditions to account for thermal creep.
- Presentation of results for air properties at standard reference conditions.
Main Results:
- Thermal creep significantly affects velocity slip, flow rate, and heat transfer rate.
- The effect of thermal creep on flow drag is negligible.
- Decreasing pressure drop or increasing Knudsen number magnifies the thermal creep effect.
Conclusions:
- Thermal creep is a critical factor in microchannel mixed convection analysis.
- Accurate modeling of microscale gas flows necessitates considering thermal creep.
- Design optimization of microfluidic devices should account for thermal creep's influence on performance.
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