Abstract

Heat transfer operations in microchannel are of special relevance in designing micro-devices involving accumulation of high heat flux. The current study explores simultaneously developing, unsteady laminar flow inside a twisted sinusoidal wavy microchannel and heat transfer involved. A square cross-sectioned channel is taken for the study. The channel is wavy in nature as well as twisted about the flow axis. The modified geometry helps in enhancing out of plane mixing of the fluid and formation of recirculation inside the flow. The evaluation is performed for a Reynolds number range of 1–100. A sinusoidal (varying with time) normal velocity component is employed at the inlet. The study was conducted over a range of pulsation amplitude and frequency. To solve the governing equations, a finite volume based method was employed. The Nusselt number data shows significant enhancement for the sinusoidal inlet velocity as compared to that of a steady case. In terms of pressure drop, the proposed design shows that at different frequencies and amplitudes, it can keep the pressure drop within admissible limits. Entropy generation is used as the measure of dissipated energy. Performance in terms of entropy generation is also reported.

摘要

微通道中的传热操作对于设计涉及高热通量积累的微型器件具有特殊的意义。目前的研究探索了在扭曲的正弦波状微通道内同时发展的不稳定层流和所涉及的热传递。研究采用方形横截面通道。该通道本质上是波浪形的，并且围绕流动轴扭曲。修改后的几何形状有助于增强流体的平面外混合和流体内部再循环的形成。对 1-100 的雷诺数范围进行评估。在入口处采用正弦（随时间变化）法向速度分量。该研究是在一定范围的脉动幅度和频率上进行的。为了求解控制方程，采用了基于有限体积的方法。与稳定情况相比，努塞尔数数据显示正弦入口速度显着提高。在压降方面，所提出的设计表明，在不同的频率和幅度下，它可以将压降保持在允许的范围内。熵产生被用作耗散能量的量度。还报告了熵生成方面的性能。