An Experimental Study on Forced Convection From a Rectangular Heated Block by Acoustic Excitation in a Channel Flow

An experimental study on forced convection from a heated block in a pulsating channel flow has been carried out. This problem is of particular interest in various thermal applications such as electronics cooling and industrial heat exchangers. A pulsating flow is imposed by an acoustic excitation at the channel inlet and a constant heat flux is given along the surfaces of the block. The impact of the important governing parameters such as the Reynolds number, the Strouhal number, and the pulsation amplitude on the heat transfer rate from the heated block is investigated in detail. The vortex shedding frequencies generated from the block are measured and the flow around the block is visualized by means of the particle visualization technique. The experimental results show that the inlet flow pulsation and the Reynolds number substantially affect thermal transport from the heated block. The heat transfer is dramatically enhanced at the frequencies of f_F=75Hz and f_F=150Hz. It is found by the flow visualization that this phenomenon is related to the intensified fluid mixing at the frequencies. The increase of the pulsation amplitude also significantly amplifies the heat transfer rate from the heated block.