Using the rarefied gas dynamic phenomenon of thermal edge flow, a micropump with a built-in thermal bimorph microvalve is proposed to provide pumping needs for systems such as micro fuel cells. A thermal bimorph cantilever used as a microvalve is located within one gas molecular mean free path away from a narrow flow channel, which connects two larger size connectors on either side. The sharp edge of the heated microvalve, whose length is several times of the gas molecular mean free path, can induce flows along its surface and into the narrow channel. Using the DSMC (Direct Simulation Monte Carlo) simulation technique, the thermal edge flow characteristics are studied computationally to determine the feasibility of the proposed design. The result for a closed simulation domains at steady state determined that a pressure ratio of 1.22 can be achieved by the proposed design. The average flow velocities in open simulation domains were found to be closely related to the heater location. This preliminary computational study has proven that with particular parameters, such as the microvalve's size and location, matching the gas mean free path, the proposed micropump with a built-in microvalve design appears to be viable to drive the thermal edge gas flows and create noticeable pressure difference to serve as a micropump.
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