脉动参数对波纹通道内传热强化的影响

采用曲线坐标系下压力与速度耦合的SIMPLER算法,数值研究了波纹通道内脉动流动与换热情况,流动Re数的范围为5~500,Pr数为0.7.计算考察了脉动参数如脉动频率和振幅对通道内强化传热和压力损失的影响.研究结果表明,流动阻力特性呈周期性余弦规律变化,换热Nu数呈正弦规律变化;频率、振幅的增大,使得阻力脉动幅度增大.受入口脉动流的影响,通道内的旋涡发生周期性的脱落、增长和迁移,从而增强了流体之间的扰动和掺混,强化了传热;传热的强化效果随着振幅的增大而增强,但在特定入口脉动流下,相同振幅不同频率下的强化效果几乎一致.

Enhanced Heat Transfer of Pulsating Flows in a Wavy Channel

A fully developed convective heat transfer inside a two-dimensional periodically wavy channel is investigated numerically with pulsating flows under a constant wall temperature. It is based on the SIMPLER(Semi-Implicit Method for Pressure Linked Equations Revised) algorithm in curvilinear body-fitted coordinates.Calculations are performed with Pr=0.7,Re=5~500 on a non-orthogonal non-staggered grid generated by elliptic equations. The effects of pulsatile parameters,such as pulsatile amplitude and frequency on heat transfer and flow friction,are studied.It shows that the vortice sweeping,diminishing and growing up due to pulsating flows enhance fluid pulsating and mixing,and lead to the enhancement of heat transfer.The intensity of heat transfer increases with the increase of Reynolds numbers and amplitudes and is independent of pulsating frequencies.The instantaneous flow resistance and Nusselts numbers present periodical cosine and sine variations, respectively.