Gas Separator with the Thermal Transpiration in a Rarefied Gas

A gas separator that makes use of the thermal transpiration in a rarefied gas is proposed, and its gas separation performance is investigated numerically. The separator consists of two kinds of flow channels with different length scales. An array of micro-channels is used to induce the gas separation effect by the thermal transpiration at intermediate Knudsen number, and two larger channels are used to accumulate the extracted molecules by the gas flows with larger flow velocities. Numerical example shows that the molar fractions of a gas in the two larger channels differ by several percent when the Mach numbers are approximately 0.2 there. The possibility of larger concentration difference is also discussed.