关键词: 微尺度, 流动, 传热, 结构, 纳米粒子, 微重力

Abstract:

The micro-pin-fin structure can effectively increase the heat transfer area and the degree of flow chaos, which has broad application prospect in aerospace, nuclear power plant, air conditioning and other fields. However, the macroscopic heat transfer mechanism may not be applicable in the microscale due to the influence of the microscale effect, which makes the flow and heat transfer in the microscale field affected by more factors. This study reviewed the effects of different structures, nanoparticles, and different gravity levels on the flow and heat transfer mechanism of micro-pin-fins, and summarized the research results in this area. It reveals that the streamlined micro-pin-fin structure has good heat transfer performance. The particles of micron or millimeter scale are liable to settle in the liquid and block the micro-pin-fin channel, while the pressure drop of nanoparticles in the micro-pin-fin channel is small, and it is not easy to precipitate and the thermal conductivity per unit volume is higher. However, the physical properties of nanofluids can only remain stable for a short period of time. The capillary attraction of the micro-pin-fin structure can supply liquid to the heated surface in time and provide stable bubble nucleation sites when it is boiling heat transfer on the earth or under microgravity, which is helpful to improve the heat transfer coefficient. The critical heat flux and the change rule of bubble departure diameter are the focus of research on micro-pin-fins boiling heat transfer under microgravity.

Key words: microscale, flow, heat transfer, structure, nanoparticles, microgravity