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制备了粒度分布为11~50nm的TiO2-H2O纳米流体,测量了纳米流体的相变潜热、表面张力和过冷度。相对于去离子水,质量分数为1%的纳米流体相变潜热减小了2.4%,表面张力增大了1.6%,过冷度降低了66.2%。纳米流体过冷度随TiO2浓度增大而降低,表面张力随TiO2浓度增大没有明显变化。运用相变动力学原理,对纳米流体过冷度降低的机理进行了分析。
The TiO2-H2O nanofluid with particle size distribution of 11 ~ 50nm was prepared. The latent heat, surface tension and undercooling of nanofluids were measured. Compared with deionized water, the latent heat of nanofluid with mass fraction of 1% decreased by 2.4%, the surface tension increased by 1.6% and the undercooling decreased by 66.2%. The degree of supercooling of nanofluids decreases with the increase of TiO2 concentration. The surface tension does not change significantly with the increase of TiO2 concentration. The mechanism of the reduction of undercooling of nanofluids was analyzed by using the principle of phase change kinetics.