开孔泡沫金属微结构强化传热性能的数值模拟研究

发布时间：2018-06-05 23:17

本文选题：泡沫金属 + 对流换热　；参考：《华东理工大学》2015年硕士论文

【摘要】：泡沫金属材料是一种新型的功能材料,其复杂的三维网状结构使其具有强化传热的效果,因此其在热交换方面具有广泛应用前景。但是,因为开孔泡沫金属具有非常复杂的内部结构,目前还没有其较为完善的强化传热机理及传热与阻力特性影响因素的系统研究。由于试验研究成本高,时间周期长,且其结构复杂性,使得通过试验来观察开孔泡沫金属内流体的流动情况较为不易。而数值模拟方面,目前所采用的模型存在结构简单、计算结果误差较大或模型较为精确而计算耗时且计算硬件要求太高等问题。因此,本文提出了一种简化的六面体结构模型,采用商业CFD软件,对开孔泡沫金属开展了系统的传热与阻力性能模拟分析。本文基于开孔泡沫金属的微观结构分析,提出了一种简化的六面体结构模型,通过与文献试验结果对比,验证了该模型和数值模拟方法的可靠性和准确性；基于提出的模型和方法,分析了泡沫金属内流体流场及温度场分布的特点；结合综合性能评价指标,考察分析了泡沫金属孔隙率、孔密度、材料热导率等关键参数对泡沫金属传热和阻力性能的影响,并进一步得到了该泡沫金属的传热因子j和摩擦因子f的关联式；最后,分析了不同孔结构的湍动能场、速度场、温度场及压力场分布特点,进一步从明确了泡沫金属的强化传热机理,为板泡式换热器的设计、优化和工程应用推广提供基础。
[Abstract]:Foamed metal material is a new type of functional material. It has the effect of enhancing heat transfer due to its complex three-dimensional network structure, so it has a wide application prospect in heat exchange. However, due to its complex internal structure, there is no systematic study on the mechanism of heat transfer enhancement and the influence factors of heat transfer and resistance characteristics. Because of the high cost, long time period and complicated structure, it is difficult to observe the flow of fluid in porous metal foam by experiment. However, in numerical simulation, the current model has some problems, such as simple structure, large error of calculation result or accuracy of model, time consuming and too high hardware requirement. Therefore, a simplified hexahedron structure model is presented in this paper. Commercial CFD software is used to simulate the heat transfer and resistance performance of porous metal foam. In this paper, a simplified hexahedron structure model is proposed based on the microstructure analysis of porous metal foam. The reliability and accuracy of the model and numerical simulation method are verified by comparing with the experimental results in literature. Based on the proposed model and method, the characteristics of fluid flow field and temperature field distribution in foam metal are analyzed, and the porosity and pore density of foam metal are investigated and analyzed in combination with the comprehensive performance evaluation index. The influence of material thermal conductivity and other key parameters on the heat transfer and resistance performance of foamed metal is obtained, and the correlation between the heat transfer factor j and friction factor f of the foam metal is obtained. Finally, the turbulent kinetic energy field and velocity field of different pore structures are analyzed. The distribution of temperature field and pressure field further clarified the mechanism of heat transfer enhancement of foam metal, which provided the basis for the design, optimization and engineering application of plate bubble heat exchanger.
【学位授予单位】：华东理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB34

【参考文献】