Baig Mirza Farrukh, Chen Gooi Mee, Tso Chih Ping
Centre for Advanced Mechanical and Green Technology, Faculty of Engineering and Technology, Multimedia University, Bukit Beruang, Melaka 75450, Malaysia.
Nanomaterials (Basel). 2022 Oct 28;12(21):3821. doi: 10.3390/nano12213821.
Partial filling of porous medium insert in a channel alleviates the tremendous pressure drop associated with a porous medium saturated channel, and enhances heat transfer at an optimum fraction of porous medium filling. This study pioneered an investigation into the viscous dissipative forced convective heat transfer in a parallel-plate channel, partially occupied with a porous medium at the core, under local thermal non-equilibrium condition. Solving the thermal energy equation along the Darcy-Brinkman equation, new exact temperature fields and Nusselt number are presented under symmetrical isoflux thermal boundary condition. Noteworthy is the heat flux bifurcation at the interface between the clear fluid and porous medium driven by viscous dissipation, in cases where the combined hydrodynamic resistance to fluid flow and thermal resistance to fluid conduction is considerable in low Darcy number porous medium insert. However, viscous dissipation does not affect the qualitative variation of the Nusselt number with the fraction of porous medium filling. By using AlO-Water nanofluid as the working fluid in a uniformly heated microchannel, partially filled with an optimum volume fraction of porous medium, the heat transfer coefficient improves as compared to utilizing water. The accompanied viscous dissipation however has a more adverse impact on the heat transfer coefficient of nanofluids with an increasing Reynolds number.
通道中多孔介质插入物的部分填充减轻了与多孔介质饱和通道相关的巨大压降，并在多孔介质填充的最佳比例下增强了传热。本研究率先对局部热非平衡条件下，核心部分被多孔介质部分占据的平行板通道中的粘性耗散强迫对流换热进行了研究。沿着达西-布林克曼方程求解热能方程，给出了对称等热流热边界条件下新的精确温度场和努塞尔数。值得注意的是，在低达西数多孔介质插入物中，当流体流动的组合水动力阻力和流体传导的热阻相当大时，由粘性耗散驱动的清澈流体与多孔介质界面处会出现热流分叉。然而，粘性耗散并不影响努塞尔数随多孔介质填充比例的定性变化。通过在均匀加热的微通道中使用AlO-水纳米流体作为工作流体，该微通道部分填充有最佳体积分数的多孔介质，与使用水相比，传热系数有所提高。然而，随着雷诺数的增加，伴随的粘性耗散对纳米流体的传热系数有更不利的影响。
