EHD-Enhanced Forced Convection by Oscillatory Gas Flow in Horizontal Channels

Abstract

Prior studies of enhanced forced convection by electrohydrodynamics (EHD) in a horizontal channel have revealed the existence of oscillatory flows. These oscillatory flows are the product from the interaction between the primary flow and electric body force. It has also been shown that heat transfer can be significantly enhanced when operating in this oscillatory flow mode. Thus, it is speculated that heat transfer may be further enhanced by exciting the primary flow in a frequency similar to those observed for the oscillatory flows (i.e., the so-called resonant effect). To verify this speculation, computations have been performed for primary flows with a frequency that is either a fraction or multiple of the natural frequency observed in the original oscillatory flows. The results show that an inlet flow excited at the natural frequencies produces the best heat transfer enhancement in the single-cell regime, and the enhancement increases with the Reynolds number. However, the results show an opposite trend in the multiple-cells regime.