基于碳化硅纳米流体射流冷却过程传热与流动特性研究

Heat Transfer and Flow Characteristics of Microjet Cooler with Silicon Carbide Nanofluid as Cooling Medium

聚光太阳能电池工作过程中,大部分光能转换成热能导致电池温度升高、寿命缩短、光电转化效率降低。因此,有效降低太阳能电池的温度、开发高效的电池冷却装置变得非常必要。射流冷却技术具有换热系数大、均温性好的特点,将纳米流体应用于射流换热中可充分发挥射流技术与纳米流体的换热性能好的优势,获得较好的冷却效果。使用分散法制备了碳化硅纳米流体,设计了一种冲击射流与微通道结构相耦合的热沉,并分别以碳化硅纳米流体与水作为工质,对其传热和流动特性进行了数值研究。结果表明:采用纳米级粒子明显改善工质的传热特性,可以使聚光太阳能电池在1800倍聚光条件下高效稳定地工作,同种条件下比水冷却表面温度低7℃,换热系数提高12.2%。数值模拟结果为碳化硅纳米流体进一步研究提供了可靠的理论基础和数据支撑。

During the working process of concentrated solar cells,most of the light energy is converted into heat energy,which leads to increase in device temperature,shortening in life and decrease in photoelectric conversion efficiency.Therefore,i t is necessary to develop efficient cooling devices to effectively dissipate the heat to keep sufficiently low temperature of the solar cells.Jet cooling technology has the characteristics of high heat transfer coefficient and uniform distribution of temperatu re.Perfect cooling performance of microjet cooler can be obtained when using nanofluid as the cooling medium.Silicon c arbide nanofluids were prepared by using dispersion method,while a heat sink coupled with impingent jet and microchannel structure was designed in this work.The heat transfer and flow characteristics of the heat sink with silicon carbide nanofluids and w ater as cooling medium were studied numerically.It is observed that the concentrating solar cell can work efficiently and stably aft er shinning concentrating light for 1800 times,when the silicon carbide nanofluid was employed as cooling medium.Compared with water,the silicon carbide nanofluid can reduce the surface temperature by 7℃and increase the heat transfer coefficient by 12.2%.The numerical results provide a reliable theoretical basis and data support for the further study of microjet cooler.