Analysis of ultrasonic composite pulsating heat pipe reinforced phase change material heat storage research

Abstract

Studies have shown that ultrasonic waves can enhance heat transfer in Pulsating Heat Pipes, it also enhances the heat storage of Phase Change Materials, however, there are few studies on ultrasonic composite Pulsating Heat Pipes reinforced phase change material heat storage. In this paper, a phase change material heat storage device under ultrasonic field is designed, and the enhanced heat transfer performance of ultrasonic composite Pulsating Heat Pipes is studied and analyzed. Experimentally observed the change of heat storage efficiency of the heat storage device caused by ultrasonic wave at different power and different positions. The results show that : under the same ultrasonic (28KHz)frequency, after applying power of 50W、100W and 120W ultrasonic fields on one side of the heat storage device, the heat storage efficiency increased by 55.6%、 57.5% and 67.1% respectively ; the heat transfer coefficients under power of 50W and 120W ultrasonic fields are respectively Increased by 6.1% and 12.6% ; after applying 50W、100W and 120W ultrasonic fields on both side of the heat storage device, the heat storage efficiency increased by 44.5% 、 60.4% and 73.4% respectively, and the heat storage efficiency increased non-linearly. Then the heat storage process was analyzed, and it was found that the heat transfer coefficient fluctuated, and the heat transfer coefficient reached the maximum when the phase transition temperature was just reached. In addition, it was found that ultrasonic waves combined with Pulsating Heat Pipes enhanced heat transfer, which significantly shortened the start-up time of pulsating heat pipes, and verified the enhanced heat transfer of supercooled boiling of Pulsating Heat Pipes under ultrasonic fields; the research results can be used to design closed phase change thermal energy storage units, would provide useful inspiration for further development and application of Pulsating Heat Pipes and Phase Change Materials with ultrasonic.