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以水作为工质,实验研究了EHD(Electrohydrodynamics)对水套管式换热器内对流换热过程的强化作用机理。实验中,在水套管换热器换热管中心设置一直流式高压电极,电极电压DC设置范围为0～40 kV,分别进行了5组不同流量下不同电压值的组合强化实验。实验结果表明:不同管内流量条件下电场对管内传热过程均有不同程度的强化作用,当流量为0.1 m3/h时,其电场强化系数θ最大,为1.224;流量为1.0 m3/h时,电场强化系数θ最小。实验证实了电场对于以水为工质的对流传热过程具有强化作用,但电场强化效果具有对流量变化敏感性的特点,同流量下存在最佳强化电压值而非电压值越高强化效果越大。
Using water as the working fluid, the mechanism of the enhancement effect of EHD (Electrohydrodynamics) on the convective heat transfer in a water jacket and tube heat exchanger was experimentally studied. In the experiment, a DC high voltage electrode was set up in the center of the heat exchanger tube of water jacket heat exchanger. The setting range of DC voltage was 0 ~ 40 kV. Five different combinations of different voltage values were tested under different flow rates respectively. The experimental results show that the electric field has different enhancement effects on the heat transfer inside the tube under different flow conditions. When the flow rate is 0.1 m3 / h, the maximum electric field enhancement coefficient θ is 1.224. When the flow rate is 1.0 m3 / h, The electric field enhancement coefficient θ is the smallest. Experiments show that the electric field has a strengthening effect on the convective heat transfer process using water as the working fluid, but the electric field enhancement effect has the characteristics of sensitivity to the change of the flow rate. Under the same flow rate, there exists the optimum enhanced voltage value rather than the higher voltage value. Big.