纳米流体对倾斜朝下加热面沸腾换热特性的影响

Influence of Nanofluids on Boiling Heat Transfer Characteristics of Inclined Downward-facing Heating Surface

本文通过在工质中加热不同纳米颗粒进行倾斜朝下表面的池沸腾实验来研究纳米材料改善沸腾传热的特性。常压下,倾斜角为0°、15°、30°时,在去离子水,体积浓度为0.01%、0.02%、0.05%的Al2O3纳米流体,体积浓度为0.001%、0.005%、0.01%的Cu-20纳米流体,体积浓度为0.01%的Cu-100纳米流体的工况下进行池沸腾试验。同时利用高速摄像设备对气泡的运动进行图像采集,结合试验结果对纳米流体影响沸腾传热的特性进行研究。研究表明:相较于去离子水,Al2O3纳米流体的换热系数增加了23.1%,而Cu-20纳米流体的换热系数增加了42.5%,Cu-100纳米流体的换热系数增加了92.9%;对于Cu-20纳米流体,体积浓度变大,换热系数增加。

This paper aims to investigate how nanometer materials improve boiling heat transfer characteristics through a pool boiling experiment from a downward-facing surface at atmosphere pressure.Under inclined angle 0°,15°and 30°,several pool boiling experiments were conducted in deionized water and different nanofluids.Visualization of boiling phenomena and bubble movement were recorded by utilizing a high-speed digital camera.Compared with deionized water,boiling heat transfer coefficient increases by23.1% for Al2O3 nanofluids,42.5% for Cu-20 nanofluids and 92.9% for Cu-100 nanofluids.It is found that boiling heat transfer coefficient increases with the volume concentration for Cu-20 nanofluids.