Effect of Blockage Ratio on Heat Transfer Enhancement in a Channel by Flow Pulsation

Experiments are performed to investigate heat transfer enhancement from a heated square cylinder in a channel by pulsating flow. For all the experiments, the amplitude of the pulsating flow is fixed at A = 0.05. The effects of the pulsating frequency (0 Hz < f_p < 60 Hz) and the blockage ratio of the square cylinder (β = 1/10, 1/8, and 1/6) on convective heat transfer are examined. The “lock-on” phenomenon is clearly observed for a square cylinder in the present flow pulsation. The influence of blockage ratio on heat transfer enhancement is examined. The experimental results show that as the blockage ratio decreases, the heat transfer enhancement is more pronounced and lock-on regime broadens.