换热管内插扰流子的数值模拟研究

Numerical Study on Flow Characteristics and Heat Transfer for a Circular Tube with Turbulators

针对强化换热时较难避免的压降损失问题,以数值模拟为手段,对比分析了换热管中安装V字折流板(V-baf)、柱状扰流子(C-rod),以及旋流子(S-gen)等扰流元件后,流体流动和换热情况。结果表明:扰流元件的加入,可以一定程度上强化传热;总结文献中已有的换热性能评价标准,综合考虑换热强化和压降损失,发现PEC(Performance Evaluation Criterion)是一种容易理解、易于计算的评价指标;经过对比3种扰流子的换热效果,其中旋流子诱导管内流体产生旋转流动,旋转流动可以使得流体在径向发生混合,增大核心区流体温度均匀程度,符合二次流强化与核心流强化原则;同时,旋转流动持续距离长,可以保持较长距离不衰减,换热综合效果较好。

Regarding to heat transfer enhancement always along with the pressure drop penalty, the study compared and analyzed flow characteristics and heat transfer in the circular tube with ‘V’-baffle(V-baf), Center-rod(C-rod), and Swirl-generator(S-gen) using numerical simulation. The results showed: turbulators can improve heat transfer. PEC(Performance Evaluation Criterion) can be easily understood and calculated, which considers both heat transfer enhancement and pressure drop penalty. Compared with C-rod and V-baf, S-gen can induce swirl flow, which can enhance flow mixing in radius direction, increasing temperature uniformity in the core flow. This is according to the enhancement principle of secondary flow and core flow. Meanwhile, the swirl flow can maintain a long distance with little decaying, which has great heat transfer enhancement.