TiO_2-H_2O纳米流体热物性研究

Investigation on thermal properties of TiO_2-H_2O nanofluids

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。

TiO2-H2O nanofluids whose particle size ranged from llnm to 50nm was prepared. The latent heat of melting, the surface tension and the degree of supercooling of TiO2-H2O nanofluids were measured experimentaly. Com- pared with deionized water, the latent heat of melting of nanofluids （1 % mass fraction）reduced 2.4 %, the surface tension increased 1.6%,and the degree of supercooling reduced 66. 2%. With the increase of concentration of TiO2-H2O nanoflu- ids, the degree of supercooling reduced correspondingly, but the surface tension had no obvious change. The reduction of de- gree of supercooling of nanofluids was analyzed based on the theory of phase change dynamics.