建立了碳遮光石英气凝胶传热机制及热性能数值模拟方法,在交叉立方阵列导热模型、热辐射传输谱带模型、辐射导热耦合传热模型基础上,采用蒙特卡罗方法与有限体积法数值模拟了气凝胶内的热辐射传输及辐射导热耦合传热,并以表观导热系数描述气凝胶传热性能.以某石英气凝胶为例,定量模拟了热性能、各种传热方式的作用及温度依赖性,分析了应用Rosseland扩散近似引起的误差.
Abstract A numerical simulation method was proposed for predicting heat transfer mechanism in a carbon opacified aerogel and its thermal performance.Based upon physical models including cubic array model for solid and gas combined conduction,spectral band model for thermal radiation transfer,coupled conduction and radiation heat transfer model,the radiation and coupled heat transfer processes in aerogels were simulated by Monte Carlo and finite volume methods,respectively.The heat transfer performance was characterized by apparent thermal conductivities for aerogels.In addition,the thermal performance,the roles of various heat transfer modes and their dependence on temperature were simulated quantitatively for a specified aerogel.Finally,the discrepancy in using Rosseland approximation method was analyzed.
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