Thermal transpiration based pumping and power generation devices

A combustion-driven thermal transpiration-based combustor is presented. The combustor was successfully applied in a self-sustaining gas pump system having no moving parts and using readily storable hydrocarbon fuel. Thermal transpiration was accomplished by meeting two essential conditions: (1) gas flow in the transitional or molecular regime using glass microfiber filters as transpiration membranes and (2) a temperature gradient through the membrane using catalytic combustion downstream of the membrane. The effect of the transpiration membrane pore size on the performance of the gas pump was studied, and the experimental result which was quantitatively consistent with theoretical predictions was reported. The gas pump system was then converted to a novel, complete portable power generation system by incorporating a single-chamber solid-oxide fuel cell (SOFC). The SOFC exhibited a maximum power density of 40 mW/cm² at the temperature and fuel/oxygen concentrations within the transpiration gas pump.