泡沫陶瓷多孔介质内流体流动及表面传热模拟

Simulation of fluid flow and surface heat transfer in porous media with foam ceramics

中文关键词: 泡沫陶瓷碳化硅  三维模拟  流动传热

英文关键词: SiC foam ceramics  three dimensional simulation  flow and heat transfer

中文摘要:

      气隙扩散蒸馏脱盐技术利用具有大比表面积的多孔介质作为蒸发器，海水在多孔介质内部流动并在表面蒸发，多孔介质起到了强化液体蒸发的作用;但由于多孔介质结构极其复杂，很难使用传统的实验技术从微观水平观测到多孔介质孔隙通道内流体的流动状态以及传热现象。针对此问题采用计算机数值模拟方法，拍摄实际碳化硅泡沫陶瓷CT图片，构建三维模型进行有限元模拟分析。结果表明，多孔介质内流体会优先通过较大孔隙通道。流体在多孔介质表面向环境空气的散热量随孔隙密度增大而增大，孔隙密度从10提高至30 PPI，散热量提高约1.43倍。进口热流体与环境空气温差越大，向环境的散热量越大，孔隙密度在30 PPI条件下，进口热流体温度从49.38增加至68.67 ℃，散热量提高近2.07倍。

英文摘要:

      The air-gap diffusion distillation desalination technology utilizes the porous medium with large specific surface area as the evaporator; seawater flows inside the porous medium and evaporates on the surface; Which enhances liquid evaporation. However, due to the extremely complex structure of porous media, it is difficult to observe the fluid flow state and heat transfer phenomenon in the pore channels of porous medium from the microscopic level using traditional experimental techniques. To solve this problem, the computer numerical simulation method was used to take CT images of actual SiC foam ceramics, and built a three-dimensional model for finite element simulation analysis. The results show that the flow in porous media will preferentially pass through larger pore channels. The heat dissipation from fluid to ambient air on the surface of porous media increases with the increase of pore density. The pore density increases from 10ppi to 30ppi, and the heat dissipation increases by about 1.43 times. The greater the temperature differ-ence between the inlet hot fluid and the ambient air, the greater the heat dissipation to the environment. Under the condition of pore density of 30 PPI, the temperature of the inlet hot fluid increases from 49.38℃ to 68.67℃, and the heat dissipation increases by nearly 2.07 times.