Aerogel, a highly porous material with less than several percent of solids, has been utilized in applications requiring high precision thermal managements due to its extremely low thermal conductivity. Combining the advantages of high porosities and low thermal conductivities, aerogels were used as thermal creep membranes in Knudsen Compressors, micro/meso-scale pumps/compressors with no moving parts. Heating one side of the thermal creep membrane to create a temperature gradient, a Knudsen Compressor is operated based on the rarefied gas phenomenon of thermal creep to create flows and to induce a pressure gradient from the cold side to the hot side of the membrane. Adding carbon particles in silica aerogels creates an optically thick, opacified carbon aerogel that can absorb radiation energies to heat up one side of the aerogel membrane in a Knudsen Compressor to create thermal creep flows. An analytical model was developed to predict the temperature profile inside of the carbon opacified aerogel thermal creep membrane for the Knudsen Compressor. Applying this temperature model, pressure ratios achieved by the optically heated Knudsen Compressors for given operating conditions were also studied and correlations between the membrane thickness and the maximum pressure increase were determined.

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