Electrohydrodynamic-Enhanced Natural Convection Heat Transfer in a Vertical Corrugated Duct

The current study is concerned with heat transfer enhancement by electrohydrodynamic within a vertical duct enclosed by a corrugated wall. The numerical simulation was performed for different corrugation profiles and various collector electrode configurations for Rayleigh numbers between 104 and 106 and the applied voltages in the range of 14 to 18 kV. A descriptive enhancement factor: the ratio of the average Nusselt number affected by electrohydrodynamic to the average Nusselt number without electrohydrodynamic is used to evaluate the capability of the heat transfer augmentation. The results demonstrate the sensitivity of the heat transfer enhancement to the corrugation profile and the location of the collector electrode. It is shown that the enhancement factor in the presence of the electrohydrodynamic reaches about 4.73 for triangular corrugation. Also, the results indicate that the enhancement factor grows for higher applied voltages and lower Rayleigh numbers. As the main goal and the final step, the electrohydrodynamic efficiency is defined as the rate of the enhancement factor by the electrohydrodynamic actuator to the electric power consumption. The results show that the triangular corrugation is more beneficial than the other configurations at Rayleigh number of 104 and the applied voltage of 14 kV.