Modelling and experimental investigation of a thermally driven self-oscillating pump

This paper explores the pumping characteristics and behaviour of a thermally driven self-oscillating pump. The pump consists of a single wickless capillary tube with a circular cross-section. The tube is closed at one end and has a T-section with two check valves at the other end to provide for a one directional flow. An experimental setup was built to investigate the output mass flow and pressure head of the pump. During the experiments, the performance of the check valves had a negative influence on the output mass flow. To determine this influence, a video analysis of the fluid oscillation without the check valves was conducted and compared to results with check valves. The average output mass flow with valves was approximately 0.0010. kg/s with a maximum measured pump flow of 0.0013. kg/s. The maximum pressure head delivered was 0.25. bar. A numerical model of the vapour bubble oscillation was developed to get a better understanding of the pump and its working principles. The model is based on the conservation of mass, momentum and energy, and resulted in a non-linear system of coupled differential equations. Overall, the experiments conducted with the thermally driven self-oscillating pump have shown that the pump has good potential to be used in aerospace applications.