微翅片扁管中纳米流体的流动换热特性研究

An Experimental Study on Flow and Heat Transfer Characteristics of Nanofluids in Micro-fin Flat Tube

本文对SiC-水纳米流体在3种多孔平行流矩形通道扁管中的流动与换热特性进行了实验研究。第一种扁管是光滑管,另外两种是带有不同间距的微翅片结构的管道。纳米流体的体积分数为0.005%、0.01%和0.1%,Re范围为150～5300。实验结果表明:微翅片结构对纳米流体的流动特性没有明显的影响;微翅片肋片间距对纳米流体的换热特性有一定的影响。微翅片的存在引起纳米流体在微翅片管段的强化程度低于光滑管道。最后,利用性能评价标准对纳米流体的综合性能进行了评定,表明在光滑管中Re≈5100时,0.01%的纳米流体的PEC达到最大值为1.68。

This study experimentally investigated SiC-water nanofluids flow and heat transfer characteristics in three types of structure multiport rectangular minichannel flat tube, including smooth tube and micro-fin tube with two different spacing of fins. The volume concentrations of nanofluids is 0.005%, 0.01% and 0.1%. The range of Reynolds number is 150-5300.The experimental results indicate that the micro-fin structure has no effect on the flow characteristic of nanofluids.However, the spacing of micro-fin has some effect on the heat transfer characteristic of nanofluids.The increase ratio of nanofluids heat transfer in micro-fin tube is lower than that of smooth tube,which attributes to the presence of micro-fin. Finally, it is shown that the maximum PEC of 0.01%nanofluids is 1.68 at Re ≈5100 in smooth tube.