分别以0、0． 031%、0． 062%、0． 155%、0． 248% 浓度的Al₂O₃-R141b 纳米制冷剂为工质，在水力直径为1． 33mm 的矩形铝基微细通道内进行了流动沸腾实验，研究了不同浓度纳米制冷剂实验后槽道表面能的变化情况． 结果表明: 加入少量纳米颗粒后，壁面形成大量的活化核心，使得沸腾起始点ONB 提前，强化了传热; 浓度为0． 062% 纳米制冷剂的强化传热效果最好，传热系数比纯制冷剂最大可提高48． 1% ; 当纳米颗粒浓度超过最佳浓度而继续增大时，颗粒在表面沉积现象越来越严重，使槽道表面能增大，换热热阻也随之增大，强化传热效果反而依次降低． 浓度为0． 031%、0． 062%、0． 155%、0． 248% 纳米制冷剂实验后的槽道表面能，比槽道原始表面能分别增长了0． 47、1． 39、1． 89、2． 14 倍．

The nano-refrigerants respectively of 0,0. 031%,0. 062%,0. 155% and 0. 248% ( volume fraction) Al₂O₃-R141b particles,were taken as the working fluids to perform flow boiling experiments in the aluminum-based rectangular microchannels of a hydraulic diameter of 1. 33mm,so as to reveal the influence of the nanoparticle concentrations on the surface energy of the microchannels after the experiments.The results show that ( 1) after adding a small amount of nanoparticles,a massive amount of activation nucleuses form on the wall surface,which brings forward the onset of nucleation boiling ( ONB) and then enhances the heat transfer; ( 2) the nanorefrigerant of 0. 062% Al₂O₃-R141b achieves the best effect in enhancing the heat transfer,and its heat transfer coefficient can be increased by a maximum of 48. 1% in comparison with that of pure R141b refrigerant; ( 3) when the nanoparticle concentration is greater than the optimal concentration of 0. 062%,the particle deposition on the surface becomes serious with the increase of the nanoparticle concentration,which causes the surface energy and heat flow resistance of microchannels to increase,but with a decrease in the heat transfer enhancement; and ( 4) the surface energy of the microchannels treated with the nano-refrigerants respectively of 0. 031%,0. 062%,0. 155%,0. 248% Al₂O₃-R141b particles,increases respectively by 0. 47,1. 39,1. 89 and 2. 14 times,in comparison with that of the original microchannels before the experiments.