Thermally Induced Flow Analysis for Narrow Channels Exposed to Temperature Gradient

The Knudsen pump uses the molecular Knudsen effect to transfer fluid without power or moving parts. The Knudsen pump has shown promise for various applications in microdevice technology, particularly in microfluidics, where precise control and manipulation of small volumes of fluids are essential. However, the lack of heat transfer engineering instruments is a major barrier to the development of microdevice technology such as narrow channels and microchannels. This paper investigated the effects of using different materials and channel diameters (6, 8, and 10 mm) in a single-stage Knudsen pump on temperature distribution. The experimental setup consists of a heater, a heat sink, and narrow channels fabricated from glassGlass, aluminum, and copper. The test area along the narrow channel is subjected to a temperature gradientGradient by placing a heater on one side and a heat sink on the other. The heater was set to a temperature of 200 °C. The time–temperature diagram of the narrow channel was evaluated, and it was discovered that the Knudsen pump can generate a flow of gas despite the absence of any moving parts or other sources of power from the outside. Hence the observation of thermally induced flow in the narrow channel is significant evidence that there is indeed flow occurring in the Knudsen pump.