Natural convection from a vertical cylinder in a thermally stratified porous medium
Natural convection from a vertical cylinder in a thermally stratified porous medium
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热分层多孔介质中垂直圆柱体的自然对流
DOI：
10.1007/s002310050278
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发表时间：
1999
影响因子：
2.2
通讯作者：
Jui
中科院分区：
文献类型：
--
作者：
C.;Jui
分析了嵌入热分层多孔介质中的垂直圆柱体附近的非达西自然对流问题。对于环境温度随圆柱体高度线性增加的情况，得到了非相似解。本研究使用广义流动模型来包括宏观粘性项和微观惯性力的影响。此外，能量方程中还考虑了热分散效应。因此，这项工作的主要目的是研究热分层和非达西流动现象对自由对流流动和传热特性的影响。研究发现，该问题取决于六个参数，即局部热分层参数 xi、边界效应参数 Bp、修正格拉霍夫数 Gr*、壁温指数 m、曲率参数 ω 和基于孔径 Rad 的修正瑞利数。详细讨论了这些控制参数对局部传热参数的影响。此外，还提供了选定的热分层参数值下的代表性速度和温度分布。一般情况下，局部传热参数随着m、ω、Rad值的增大而增大；而随着 Ψ、Bp 和 Gr* 值的增大而减小。
The problem of non-Darcy natural convection adjacent to a vertical cylinder embedded in a thermally stratified porous medium has been analyzed. Nonsimilarity solutions are obtained for the case that the ambient temperature increases linearly with height of the cylinder. A generalized flow model was used in the present study to include the effects of the macroscopic viscous term and the microscopic inertial force. Also, the thermal dispersion effect is considered in the energy equation. Thus, the main aim of this work is to examine the effects of thermal stratification and non-Darcy flow phenomena on the free convection flow and heat transfer characteristics. It was found that the present problem depends on six parameters, namely, the local thermal stratification parameter ξ, the boundary effect parameterBp, the modified Grashof number Gr*, wall temperature exponentm, the curvature parameter ω, and the modified Rayleigh number based on pore diameter Rad. The impacts of these governing parameters on the local heat transfer parameter are discussed in great detail. Also, representative velocity and temperature profiles are presented at selected values of the thermal stratification parameter. In general, the local heat transfer parameter is increased with increasing the values ofm, ω, and Rad; while it is decreased with increasing the values of ξ, Bp, and Gr*.