微细通道纳米制冷剂流动沸腾阻力特性

发布时间：2018-03-07 05:38

本文选题：微细通道　切入点：纳米制冷剂　出处：《化工进展》2016年12期 　论文类型：期刊论文

【摘要】：分别以质量分数为0.2%、0.5%和0.8%的Al2O3-R141b纳米制冷剂和纯制冷剂R141b为工质,在水力直径为1333μm的矩形微细通道内进行了流动沸腾实验,分析了纳米颗粒浓度对工质两相摩擦压降的影响,对比了实验前后换热壁面的表面能。研究结果表明:实验工况相同时,质量分数为0.2%、0.5%和0.8%的纳米制冷剂的两相摩擦压降均比纯制冷剂低,降低的最大幅度分别约为11.6%、14.8%和19.2%;实验后纳米颗粒在换热壁面附着,使壁面表面能增大,质量分数为0.2%、0.5%和0.8%的纳米制冷剂实验后换热壁面表面能比实验前分别增大了1.26倍、1.44倍和1.91倍,减小了换热表面的粗糙度和提高其润湿性,使得工质两相摩擦压降减小;根据实验值与模型预测值的对比情况,对Qu-Mudawar模型进行修正,拟合得到的关联式能很好预测实验值,平均绝对误差为9.78%。
[Abstract]:The flow boiling experiments were carried out in a rectangular micro-channel with a hydraulic diameter of 1333 渭 m with 0.5% and 0.8% mass fraction of Al2O3-R141b nano-refrigerant and pure refrigerant R141b, respectively. The effect of the concentration of nanoparticles on the two-phase friction pressure drop was analyzed. The surface energy of heat transfer wall was compared before and after the experiment. The results showed that the two-phase friction pressure drop of the nano-refrigerant with 0.2% and 0.8% mass fraction was lower than that of the pure refrigerant under the same experimental condition. The maximum decrease was about 11.610% and 19.2%, respectively. After the experiment, the nanoparticles attached to the heat transfer wall, which made the wall surface energy increase. The wall surface energy of 0.5% and 0.8% nano-refrigerants increased by 1.26 times and 1.91 times, respectively, which reduced the roughness and wettability of the heat transfer surface, and reduced the friction pressure drop. According to the comparison between the experimental value and the predicted value of the model, the Qu-Mudawar model is modified. The fitting correlation can predict the experimental value well, and the average absolute error is 9.78.
【作者单位】：华南理工大学机械与汽车工程学院;
【基金】：国家自然科学基金项目(21276090)
【分类号】：TK124

【相似文献】