Heat Transfer Enhancement In Rectangular Channels By Electrohydrodynamics

With the development of technology, the electronic products are more and more powerful and the number of electronic components becomes larger and larger. More electronic components yield larger electric power consumption and higher heat flux. In order to cool the electronic products effectively, the active heat transfer enhancement method by EHD has been widely used and developed. This method has many advantages such as simple construction, little energy consumption and less noise. Many researchers have studied EHD. However, most of them focus on experimental research. It is not until nowadays that some numerical researches have been made, but the effect of the horizontal position of electrodes, the number of electrodes and the way of ground are not reported in the open literature. Based on the above analysis, this thesis builds a EHD-based multiple physical coupling model and changes the geometry parameters to enhance the heat transfer performance in rectangular channels by EHD effect.The numerical study changes the horizontal position of electrodes when the traditional single wall has heat flux. The parameters of the research include the distance of the electrodes and the entrance d, the distance between electrodes l and the electrodes number n. Through the numerical research, it is found that if d is larger, then the temperature of vortex is higher and the heat transfer enhancement factor ζ is smaller. If increasing l, then the electrodes’barrier effect is smaller and the heat transfer enhancement factor ζ will become larger. As the number of electrodes increases, the heat transfer enhancement factor ζ becomes larger at first, and then reaches a maximum value, and the value is about 4.8 in this thesis.When both of the upper and the under wall need to be cooled, this research extends the attention to changing the arrangement of electrodes and the ground configuration. The result shows that if the two electrodes are respectively close to the upper wall and under wall, the ability of the heat transfer will be enhanced. This conclusion will not be changed by changing the electrodes distance L, the distance of the electrodes and the entrance d. When the ground angle θ is changed, the heat transfer enhancement factor will change consequently. If the ground angle θ is changed, the electric potential and charge density will change, the electric field force will change and then the flow field and temperature field will also change.