Numerical and experimental study of a two-phase thermofluidic oscillator with regenerator achieving low temperature-differential oscillation

Abstract In this work, a two-phase thermofluidic oscillator with regenerator is numerically and experimentally investigated, focusing on the mechanism of regenerator in lowering the onset temperature. A modified acoustic-electric analogy model, considering the thermophysical properties of regenerator, is developed to predict the onset temperature difference and resonant frequency at onset point, which is then verified by experiments. The influences of the material and type of regenerator on the onset temperature difference, resonant frequency and pressure amplitude have been investigated. By inserting the regenerator packed with copper mesh screens, the onset temperature difference is decreased from 35.1°C to 7.0°C, which is lowest ever reported in the literatures. Additionally, the pressure amplitude is increased from 4.5 kPa to 10.7 kPa at a hot temperature of 46°C. The merits of simple construction, free maintenance and low temperature-differential onset enable this updated two-phase thermofluidic oscillator suitable for low-grade heat harvesting.