Flow behaviors and transmission characteristics of Knudsen pump with blocked microchannels

Abstract The Knudsen pump driven by temperature difference without moving parts has exciting application prospects in waste heat utilization. The microchannels of Knudsen pump may be blocked during the fabrication and operation, which may affect the internal flow field and transmission characteristics. However, effects of blocked microchannels on the flow and transmission characteristics of Knudsen pump remains unclear. The study of flow behaviors and transmission characteristics of Knudsen pump with blocked microchannels is of great significance for fault diagnosis and maintenance. Effects of a single blocked microchannel at different positions, number of blocked microchannels, and number of series stages on flow behaviors and transmission characteristics of Knudsen pump are studied by the numerical method with slip boundary in this paper. The results show that the transmission capacity with a single blocked microchannel at different positions remains unchanged with the action of overall thermal transpiration flow and Poiseuille flow. The pressure of middle container decreases with the number of blocked microchannels, and the transmission capacity under the effect of Poiseuille flow decreases by 11.41%, 25.7%, 43.7%, and 67.4%, respectively. The unblocked microchannel flow enhances with the number of series stages, which is beneficial for reducing the impact of the blocked microchannels on the transmission capacity. As the number of stages increases, the transmission capacity decreases by 67.4%, 58.7%, 52.4%, and 47.4%, respectively.