高压电场强化空气对流传热实验及其数值模拟

Air convection heat transfer experiment of electro-hydrodynamics enhancement and numerical simulation

以空气为实验介质,对水平光管、横纹管、缩放管和螺旋槽管的强制对流传热进行了高压电场强化实验,研究了高压电场强化传热的一些基本规律。实验验证了当外加高压大于15 kV后,对强制对流传热有较好的综合传热效果,最大强化率达2.8,而阻力系数的增大倍数在1.5—1.9。并对横纹管进行了数值模拟,从场协同的角度研究了速度场与温度场夹角对传热膜系数的影响。结果表明,速度、温度梯度的大小,及两者夹角的余弦值均会影响传热效果,在三者的值都是最大的位置,其传热膜系数也最大。

The experiments were performed for the forced convective heat transfer with air through smooth tube,traverse corrugated tube,spiral tube and convergent-divergent tube under high voltage direct current to study the convective heat transfer rules of electro-hydrodynamics enhancement（EHD）.When current voltage was greater than 15 kV,the effect on heat transfer enhancement was positive, and the maximum enhancing index could reach 2.8 while the friction factor increased 1.5-1.9 times.Numerical simulations were also carried out for the traverse corrugated tube to study the effect of angle between velocity field and temperature field on the surface heat transfer coefficient by field synergy.The results show that the absolute value of velocity,temperature gradient and the cosine value of included angle between velocity field and temperature field affect heat transfer enhancement.When all the three parameters reach their maximum values,the surface heat transfer coefficient is at the optimum result.