【摘要】 为了探求新型冷却介质——纳米流体的换热效果,制备了不同粒子体积分数的氧化铝有机纳米流体,并在车用机油冷却器中进行了换热性能的试验研究。研究结果表明:添加纳米粒子能够有效提高纳米流体基础液体的换热能力,且换热能力随着粒子体积分数的增加而增高。在不同温度和温差条件下,粒子体积分数为5%的纳米流体的传热量和换热系数均超过常规冷却介质(水和防冻液)。纳米流体的黏度和流动阻力亦随着粒子体积分数增加而增加。当冷、热介质的进口温差不变时,提高冷却介质的进口温度能在明显增强换热能力的同时大幅度降低流动阻力,并且纳米流体换热能力的增幅要高于防冻液和基础液体。更多还原

【Abstract】 To investigate heat exchange effect of the new type coolant(nanofluids),alumina organic nanofluids of various particle volume fractions were produced and heat exchange characteristics in vehicle oil cooler were investigated.The results show that nanoparticle addition can efficiently enhance heat exchange capability of the base fluid,and the enhancement effect increases with particle volume fraction increasing.Under different inlet temperatures and temperature differences,both heat exchange capacity and heat exchange coefficient for the 5% nanofluids are higher than conventional coolants(water and antifreeze).Increasing volumetic fraction may also raise the viscosity and flow resistance of the nanofluids.Under the same temperature difference between cold and hot mediums,elevating cooling medium inlet temperature can considerably intensify heat exchange and dramatically reduce the flow resistance,and the heat exchange enhancement effect of nanofluids is greater than that of antifreeze and base fluid.更多还原