Theoretical Analysis And Numerical Calculation Of Heat Transer Enhancement By Corona Wind

Electrohydrodynamics is a kind of active heat transfer enhancement method. On the basis of general heat transfer condition, corona wind produced by additional high-voltage electric field can make severe turbulence round the heat transfer surface. Compared to the power consumption, it is greatly enhanced efficiency of heat transfer. People pay more attention to this method this years by the feature of EHD(electrohydrodynamics) ,which is effective,low consume and easily controlling the surface fluid.This paper focus on the numerical computation of heat transfer enhancement by EHD action on the air. Simulating the forced convection heat transfer the Corona Discharge between line-plate electrodes, we can make the conclusion about the relation between temperature field,flow field and parameters of electric field ,such as electric potential,space charge density,electrode number and arrangement. current continuity equation is built into CFD software in addition. In the model this paper introduced, electric field can intensify the heat transfer in the solution domain. The following conclusion can be drawn from the simulation results:First, air is ionized by the electric field, and ionized atom moved under the electric field force .During the movement, they may collide with each other, lead the airflow from laminar flow to turbulent flow, and finally enhance heat transfer. In the model this paper introduced, around the line electrodes the electric force mainly affects on the vertically velocity variations. In this area, Reynolds number increased greatly, the airflow change from turbulent flow from laminar flow.Second, different distance between the line and the plate makes different heat transfer effect .In this model, during 0.02m～0.08m, the smaller the distance is,the better effect of heat transfer is. The coefficient of the EHD heat transfer is 17.1 times than the coefficient without electric field when the distance is 0.02m, and 8 times when it is 0.08m.Third, different voltage between the line and the plate also make the different effect of heat transfer. During 10kv~20kv in this model, the higher voltage is ,the larger heat transfer coefficient is. There is a maximum value close to the line electrode when the voltage is 20kv,and the average heat transfer coefficient is about 11 times than that without EHD force, and this value is 8.5 when the voltage is 12kv,Finally, the number of line electrode and distance between also have a potent effect on the heat transfer coefficient. In this model, on the condition of 0.3m between two line electrode , heat transfer coefficient have the largest value, that is 11 times compared with the situation without EHD effect.As an effective means for energy conservation, EHD technique has widely application prospects in many fields . Present research is still remain in the laboratory stage, so researching this technique is of important realistic significance.