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首页> 外文期刊>Journal of Heat Transfer >Natural Convection Heat and Mass Transfer in the Vertical Cylindrical Porous Channel Under the Effects of Time-Periodic Boundary Condition
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Natural Convection Heat and Mass Transfer in the Vertical Cylindrical Porous Channel Under the Effects of Time-Periodic Boundary Condition

机译：时间周期边界条件下垂直圆柱多孔通道中的自然对流传热和传质

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Heat and mass transfer are investigated numerically with steady-state laminar natural convection through a vertical cylindrical enclosure filled with a liquid-saturated porous medium. The vertical wall is under a constant magnetic field and various durations of periodic heating boundary condition; the top and bottom surfaces are kept at a constant cold temperature. Continuity, momentum, and energy equations are transformed to dimensionless equations. The finite difference approach with the line successive over-relaxation (LSOR) method is used to obtain the computational results. This study covers the heat transfer, the temperature distribution, and the velocity field in the domain under the variation of different parameters. The code used is validated by modifying it to analyze the Nusselt number in the existing experimental literature of Izadpanah et al. (1998, "Experimental and Theoretical Studies of Convective Heat Transfer in a Cylindrical Porous Medium," Int. J. Heat Fluid Flow, 19(6), pp. 629-635). This work shows that Nusselt number decreases (with varying gradient) as the aspect ratio increases, and that it increases as the Rayleigh number increases. The centerline temperature has a proportional relationship with the heating amplitude and the heating period (as the system receives more heat) and is inversely proportional with Rayleigh number. Increasing the Rayleigh number causes increased convective velocity, which affects the position of the hot region, and causes a decrease in the temperature field. Increasing the aspect ratio results in a warm stream at the center of the cylinder, and when the time period of the heating increases, the circulation becomes faster and the intensity of the temperature contour layers decreases. In this work, a correlation for Nu as a function of the mentioned parameters is developed.
机译：通过填充有液体饱和多孔介质的垂直圆柱外壳，利用稳态层流自然对流，对传热和传质进行了数值研究。垂直壁处于恒定磁场和周期性加热边界条件的各种持续时间下；顶部和底部表面要保持恒定的低温。连续性，动量和能量方程式转换为无量纲方程式。采用线连续超松弛（LSOR）方法的有限差分法获得了计算结果。这项研究涵盖了在不同参数变化下的区域内的传热，温度分布和速度场。通过修改Izadpanah等人现有实验文献中的Nusselt编号，可以验证所使用的代码。 （1998，“在圆柱形多孔介质中对流传热的实验和理论研究”，Int.J。热流体流动，19（6），第629-635页）。这项工作表明，随着长宽比的增加，Nusselt数会减少（随梯度变化），而随着瑞利数的增加，Nusselt数会增加。中心线温度与加热幅度和加热时间成比例关系（随着系统接收更多的热量），并且与瑞利数成反比。瑞利数的增加导致对流速度的增加，这会影响高温区域的位置，并导致温度场降低。长宽比的增加会在圆柱体的中心产生暖流，并且当加热时间增加时，循环会变得更快，并且温度轮廓层的强度会降低。在这项工作中，开发了Nu与上述参数的函数关系。

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