ZrO2纳米流体的对流换热系数测定及机理浅析

建立了测量圆管内纳米流体流动与传热性能的实验系统,测量了不同粒子浓度的ZrO2/水纳米流体在雷诺数为3 000～18 000范围内的管内对流换热系数以及不同位置处纳米流体对流换热系数的变化情况.实验结果显示,在液体中添加纳米粒子显著增大了液体的管内对流换热系数,例如,在相同雷诺数时,与纯水相比,如果纳米粒子的质量浓度从1.6%增大到4.1%,则纳米流体的对流换热系数增加的比例从1.09增大到1.2.此外,从颗粒的浓度、粒径两方面分析纳米流体强化传热的机理.

MEASUREMENT AND ANALYSIS OF THE CONVECTIVE HEAT TRANSFER COEFFICIENT OF ZrO2 NANOFLUID

An experimental system is set up to investigate the convective heat transfer and flow characteristics of the nanofluid flowing in a tube. For the Reynolds number 3000~18000, the convective heat transfer coefficient of ZrO2-water nanofluid is measured. The experimental results show that compared with the convective heat transfer coefficient of the base fluid, that of nanofluid remarkably increases. For example,the ratio of h of ZrO2-water nanofluids to that of water varies from 1.09 to 1.2,while the quality fraction of ZrO2 nanoparticles increases from 1.6% to 4.1%. In order to investigate the mechanism , both quality fraction and dimension are analyzed.