共查询到19条相似文献,搜索用时 125 毫秒
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求解辐射传递的非结构混合有限体积/有限元法 总被引:1,自引:0,他引:1
本文给了一种适用于任意非结构网格的有限体积/有限元法的混合算法用于求解多维半透明吸收、发射、散射性灰矩形介质内的辐射传递.该方法使用有限元法进行角度离散,有限体积法进行空间离散.与基于辐射传递离散坐标方程的方法不同的是,该方法在迭代求解的过程中,针对每一个空间体元,所有角度方向的辐射强度同时耦合求出.通过两个算例验证了该解法的正确性. 相似文献
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用DT法求解三维圆柱体半透明介质内辐射与导热的非稳态复合换热 总被引:3,自引:0,他引:3
采用控制容积法,离散传递(DT)法,结合谱带模型,研究了第一类及第三类非线性边界条件下三维圆柱体半透明介质内辐射与导热非稳态复合换热的数值计算方法,经与区域法,改进型蒙特卡洛法的计算结果比较表明,本方法的计算结果的可信的,精度也较高。 相似文献
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非灰气体中辐射全交换面积的计算 总被引:5,自引:1,他引:4
将描术非灰气体辐射特性的指数宽带模型引入均匀离散射线法,推导了非灰气体参与介质条件下,辐射全交换面积的计算式,并计算了二维封闭体系的辐射全交换面积。结果表明,均匀离散射线法可用于模拟非灰气体中的辐射换热问题。 相似文献
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非灰介质中辐射直接交换面积的计算 总被引:2,自引:2,他引:0
用宽带胶其修正模型模拟非灰介质的辐射特性,并将它用于区域法模型,计算了非灰气体介质中表面一表面之间的辐射直接交换面积。结果表明,修正的宽带模型对气体辐射特性的描述是比较准确的,且它易于与区域法相结合。 相似文献
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碳遮光石英气凝胶传热机制与热性能数值模拟 总被引:1,自引:0,他引:1
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. 相似文献
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采用间断有限元法(discontinuous finite element method,DFEM)求解非规则形状介质内的辐射导热耦合传热问题,得到了典型非规则形状介质内辐射导热耦合传热问题的高精度数值结果.和传统连续型有限元方法不同,DFEM将计算区域划分成相互独立的离散单元,形函数的构造、未知量的加权近似以及控制方程的求解均在每一个离散单元上进行.通过在单元之间施加迎风格式的数值通量,DFEM保证了整个计算区域的连续性,因此这种方法兼具良好的几何灵活性和局部守恒性.推导了辐射传输方程和能量扩散方程的射导热耦合传热问题,得到了典型非规则形状介质内辐射导热耦合传热的高精度数值结果. 相似文献
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本文采用射线踪迹结合节点分析法和谱带模型,研究了漫反射不透明边界下吸收、发射、各向异性散射介质内的热辐射传递过程。考虑介质辐射能的入射和散射方向,导出漫反射、不透明边界、各向异性散射介质的辐射传递系数。在辐射平衡的情况下,考察了表面发射率和散射反照率对介质内辐射热流和温度场的影响。研究表明,介质不透明边界处存在温度跃迁现象,而且,内界面发射率越大,相应界面温度跃迁越小。 相似文献
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《Revue Generale de Thermique》1998,37(6):475-487
Combined radiation and natural convection in a participating medium between concentric or vertically eccentric horizontal cylinders is investigated numerically. The annular medium is considered as a gray, emitting, absorbing, and isotropically scattering gas. The equations of steady, laminar, two-dimensional, thermal, natural convection are written by using a two-cylindrical coordinate system, the stream function, and the vorticity. The finite volumes method is used to discretize the coupled equations of momentum, energy, and radiative transfer. To solve the global nonlinear algebraic equations the successive-over-relaxation iterating scheme is applied. Numerical solutions are obtained for a Rayleigh number in the range 103–105 and radiation-conduction parameter ranging from 0 to ∞. The influences of radiation-conduction parameter, Rayleigh number and other parameters on flow and temperature distributions and heat transfer are discussed. 相似文献
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L.H. Liu 《Journal of Quantitative Spectroscopy & Radiative Transfer》2002,74(1):97-114
A method is developed to analyze the transient coupled radiation-conduction in infinite semitransparent cylinders surrounded by isothermal black walls. The radiative heat source term is calculated by the radiative transfer coefficients and the transient energy equation is solved by an implicit finite difference method. The radiative transfer coefficients are deduced by use of the ray tracing method in combination with the Hottel and Sarofim zonal method. The effects of the related parameters on the transient radiative heat source and temperature distribution are analyzed. It is found that the peak of the dimensionless radial radiative heat source can be located at the interior shell of the cylinder with small optical thickness when heated by the surrounding irradiation. Treating the volume radiation as a surface radiation will result in large errors of transient temperature distribution for the cylinder with small optical thickness. 相似文献
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Jian-Feng Luo Sheng-Li Chang Xi Shen 《Journal of Quantitative Spectroscopy & Radiative Transfer》2008,109(15):2603-2612
The main objective of this paper is to extend to two-dimensional (2-D) medium the ray tracing-node analyzing method, which has already been successfully used to solve one-dimensional (1-D) problem of coupled heat transfer in a semitransparent medium. For simplicity, an infinitely long rectangular semitransparent medium with four black opaque surfaces is chosen as our studying object. A control volume method in the implicit scheme is adopted for discretizing the partial transient energy equation. In combination with spectral band model, the radiative heat source term is calculated using the radiative transfer coefficients (RTCs), which are deduced by the ray tracing method. The Partankar's linearization method is used to linearize the radiative source term and the opaque boundary condition, and the linearized equations are solved by the ADI method. Effects of absorption coefficient, refractive index and conductivity on transient cooling process in the 2-D gray rectangular medium are investigated under the condition that the radiation and convection processes cool one side of the rectangular medium while heat the remaining three sides. 相似文献