具有凹坑结构的半椭圆电热元件传热和流动特性的数值模拟

Numerical Simulation of Heat Transfer and Flow Characteristics of Semi Elliptical Electric Heating Elements with Concave Structure

为了探究表面添加凹坑结构对电热元件的平均换热特性、阻力特性及相关综合性能的影响,对具有凹坑结构的半椭圆翅片电热元件的传热和流动特性进行了数值模拟研究,以相同电加热功率的光滑表面电热元件为基准进行了比较分析。研究结果表明:凹坑结构一方面增加了电热元件的传热面积,同时在一定程度上破坏了空气横掠电热元件的热边界层和流动边界层,使边界层分离点后移,从而强化了传热。在Re=2000时,电热元件最优凹坑参数组合为d=0.8 mm、L=12 mm,其Nu值比光滑表面的电热元件Nu值增加约3.82%,综合传热性能增加约3.6%。

In order to investigate the effect of adding pit structures on the average heat transfer characteristics,resistance char-acteristics,and related comprehensive performance of electric heating elements,this article conducted numerical simulation research on the heat transfer and flow characteristics of semi elliptical finned electric heating elements with pit structures.A comparative analysis was conducted on smooth surface electric heating elements with the same electric heating power as the benchmark.The research results indicate that the concave structure not only increases the heat transfer area of the electric heating element,but also to some extent damages the thermal and flow boundary layers of the air crossing the electric heating element,causing the separation point of the boundary layer to move backward,thereby strengthening heat transfer.At Re=2000,the optimal combination of pit parameters for the electric heating element is d=0.8 mm and L=12 mm.Its Nu value increases by about 3.82%compared to the Nu value of the electric heating element with a smooth surface,and the overall heat transfer performance increases by about 3.6%.