Fluid-structure interaction of a sweeping impingement jet for cooling hot flat target

Abstract

Normal impingement jets remove heat from a hot target locally and cause non-uniform temperature due to the limited covered distance on the target. The current numerical study suggests an approach for sweeping impingement laminar jets to cover a wider distance on a hot flat plate. The approach is based on oscillating a slot impingement jet composed of two flexible plates. A sinusoidal excitation is imposed to the flexible plates to create two oscillation modes, sweeping jet (in-phase) and converging-diverging jet (out-of-phase). The study focused on the characteristics of the jet oscillation in addition to the Reynolds number. The problem is solved using the finite element method with moving mesh. The results show that the suggested oscillating jets offer an enhancement of the average Nusselt number. It is noticed a pronounced role of the amplitude of the oscillation in enhancing the Nusselt number in the out-of-phase mode where about 11.2% and 4.6% enhancements are attained with out-of-phase and in-phase modes, respectively at Reynolds number of 400 and amplitude ratio of 0.1875. It is also found that the pressure drop cannot be avoided in sweeping oscillating jets.