Numerical analysis of thermal transpiration flows for a nano-pore aerogel membrane.

Thermal transpiration flows in nano-pore aero-gel membranes are investigated for the performance optimization of a Knudsen compressor. Critical elements that drive the Knudsen compressor are its thermal transpiration membranes. The membranes are based on aerogel, or on machined aerogel. In our study, aerogel is modeled as a single microflow channel. The effects of wall temperature distribution on thermal transpiration flow patterns are examined. The flow has a pumping effect, and the mass flow rates through the channel are calculated. The results show that a steady one-way flow is induced for a wide range of Knudsen numbers. The direct simulation Monte Carlo (DSMC) method, with a variable hard sphere (VHS) model and no time counter (NTC) technique, is applied to obtain numerical solutions.