多孔泡沫金属散热模型数值模拟与分析

Numerical Simulation And Analysis Of Heat Dissipation Model Of Porous Metal Foam

中文关键词: 多孔泡沫  孔隙率  传热特性  阻力特性

英文关键词: Porous foam  Porosity  Heat transfer characteristics  Resistance characteristics

中文摘要:

      多孔泡沫金属在紧凑型换热器领域具有广阔的应用前景。本文对具有随机结构的多孔介质中的流动和传热进行了耦合分析。采用有限元法研究了不同孔隙率(30%、50%、70%和90%)泡沫多孔材料的传热特性和阻力特性。利用 作为性能评价指标，即h越大，Δp越小，换热性能越好。通过改变孔隙度和入口流速从而分析整体的换热性能。结果表明，对于换热特性，泡沫金属的对流换热在高度方向上存在明显的温度梯度，边界层沿流动方向可以很好地发展，在高流速下具有更好地换热能力。随着孔隙率的增大，流体扰动变少从而局部速度将会减小，因此换热量也会降低。对于阻力特性，随着孔隙率的减小，内部压力显著增大，压力损失也显著变大。孔隙率为70%时，多孔泡沫金属具有更高的均匀性，同时通过实验验证了模型具有一定的有效性。

英文摘要:

      Porous metal foams have broad application prospects in the field of compact heat exchangers. In this paper, the coupled analysis of flow and heat transfer in porous media with random structure is carried out. The heat transfer and resistance characteristics of foamed porous materials with different porosity (30%, 50%, 70% and 90%) were studied by finite element method. Use as a performance evaluation index, that is, the larger H, Δ P is smaller, the better the heat transfer performance. The overall heat transfer performance is analyzed by changing the porosity and inlet flow rate. The results show that for the heat transfer characteristics, the convective heat transfer of metal foams has an obvious temperature gradient in the direction of height, and the boundary layer can develop well in the direction of flow, and has a better heat transfer ability at high flow rate. As the porosity increases, there will be less fluid disturbance and therefore less local velocity and therefore less heat transfer. For the resistance characteristics, with the decrease of porosity, the internal pressure increases significantly and the pressure loss also increases significantly. When the porosity is 70%, the porous metal foams have higher uniformity, and the validity of the model is verified by experiments.