【作者】 门玉宾；

【导师】 何玉荣；

【作者基本信息】 哈尔滨工业大学 ， 热能工程， 2010， 硕士

【摘要】 随着传热技术和材料应用的发展,人们对于材料传热性能的要求逐渐提高,寻找传热性能好的载热材料已经成为必然的趋势。液态金属较好的流动和传热特性,已经成为了解决此问题的关键之一,而由于纳米流体的广泛应用,作为当代的高新技术之一,纳米流体有较广泛的应用前景。但是在强化传热和复杂流动中的机理仍没有进行过深入的研究,在实际应用中还有一定的困难。鉴于纳米技术表现出的强大生命力和在热科学领域中潜在的广阔应用前景,本文主要研究了以液态金属及其纳米流体为换热介质,运用商业软件,考虑运用单相流体模型、DPM模型和E-E模型,研究其在强制对流、自然对流情况下的流动和换热效果。在强制对流的工况条件下,经模拟计算表明:液态金属镓的流动和传热特性明显的高于相同条件下水的流动和传热特性,而加入了纳米级颗粒的液态金属纳米流体流动和传热的特性也明显的高于相同条件下的液态金属流体,其中选用不同的模型如单相流体模型、DPM模型、E-E模型得到的流动和传热结果仍有一定的区别。在自然对流的工况条件下,经模拟计算表明:液态金属流体三维的流动和换热的特性与简化的二维的模型模拟的流动和换热的特性基本一致,而加入纳米级颗粒的纳米流体流动和换热的基本特性与纯液态金属的流动和换热特性其趋势是基本一致的,而且在一定条件下传热效果明显增加,随着格拉晓夫数的增加,他们的流动和换热的特性也有较大幅度的变化,由开始以导热为主,变为对流换热占据了较大的比例。更多还原

【Abstract】 With the development of heat transfer and material application, it has been a trend that we need a kind of material with a good heat carrying ability. Liquid metal has a good heat transfer characteristic, so it has been a key point to this problem. However, the research, especially the investigation on flow and heat transfer characteristics of nanofluids is just at its outset and far from being understood.In view of the fact that the power of the nanotechnology and its many potential applications in the thermal science, the flow and heat transfer characteristics of nanofluids are numerically investigated under the forced convection and natural convection conditions with a commercial software using the single phase model, DPM model and E-E model in this thesis.Under the forced convective condition, the results show that the characteristic of liquid metal fluid is better than water in flow and heat transfer under the same condition. Moreover, the characteristic of liquid metal nanofluids is more better than liquid metal fluid in flow and heat transfer. At the same time using the single phase model, DPM model and E-E model, the results are a bit different.Under the natural convective condition, we obtained the flow field, vector field and temperature field in 2D and 3D models. Both results are almost identical. Therefore we can perform the simulation work using a 2D model instead of a 3D model. For the liquid metal nanofluid, it has a similar trend in the flow and heat transfer characteristic, but it can enhance the natural convective heat transfer under a special condition. With increasing the Gr number, the flow and heat transfer characteristics of the fluids change greatly from conduction to convection.更多还原