Abstract

This work is focused on corrugated bottoms role as a means to improving heat performance of cavities filled by two superimposed fluid layers. Physical models examined are square cavities with bottoms subjected to a constant heat flow and sidewalls maintained at cold temperatures. Cavities treated here have been filled with two different fluids. Computational code based on finite volume method has been used to solve two fluid region equations and predict thermal and hydrodynamic fields in two-layer system. Interface between two fluids was assumed to be fixed with null velocities and to be thermally conductive across two fluid regions, where heat flow continuity at this domain boundary was adopted. Mesh has been treated using curvilinear mesh grid in order to take into account corrugated bottoms. Different Rayleigh number values “(10³ ≤ Ra ≤ 10⁶)” and different filling rates of two flu ids “(1/3 ≤ h/L ≤ 2/3)” are included in this parametric study. Main objective of our research is focused on corrugated bottoms as a way to improve thermal performance of cavities filled by two fluids, we have opted to examined various forms of corrugation, based on wavelength effects “(0.1 ≤ b ≤ 0.5)” and amplitudes effect “(0 ≤ a ≤ 0.1)” of corrugated backgrounds. Results shows that corrugated bottoms provide an efficient means to improve thermal performances of cavities filled by two fluids. Also, it has been shown that optimal values of wave length and amplitude of corrugated bottoms exist where heat transfer rate reaches its maximum.

摘要

这项工作的重点是波纹底部作为改善由两个叠加流体层填充的空腔的热性能的一种手段。检查的物理模型是方形空腔，底部承受恒定的热流，侧壁保持低温。这里治疗的腔体充满了两种不同的液体。基于有限体积法的计算代码已被用于求解两个流体区域方程并预测两层系统中的热场和流体动力场。假定两种流体之间的界面以零速度固定，并且在两个流体区域之间具有导热性，其中采用了该域边界处的热流连续性。网格已使用曲线网格处理，以考虑波纹底部。不同的瑞利数值“(10³ ≤ Ra  ≤ 10 ⁶ )”和两种流体的不同填充率“(1 / 3 ≤  h / L ≤ 2/ 3)”包含在该参数研究中。我们研究的主要目标是将波纹底部作为一种改善由两种流体填充的腔体的热性能的方法，我们选择根据波长效应“(0.1 ≤ b ≤ 0.5)”和振幅效应检查各种形式 的 波纹“（0≤ 一个 ≤ 0.1)” 的波纹背景。结果表明，波纹底部提供了一种有效的方法来改善由两种流体填充的空腔的热性能。此外，已经表明，波纹底部的波长和振幅的最佳值存在于传热率达到最大值的位置。