Heat Transfer from a Hybrid Pulsating and Swirling Air Jet Impingement

With decrease in size of electronic equipment's, effective heat removal is a major challenge these days. Present work focuses on implementation of a novel hybrid method which helps attain heat transfer enhancement. An experimental investigation is carried out to study effect of pulse air jet on local heat transfer distribution of a flat surface. Effect of nozzle to plate distance (z/d = 2 to 6), Reynolds number (5000 to 9000), pulsating frequency (f = 0.07 to 2.03 hz) and Strouhal number (Sr = 6.7e-5 to 0.0029) are studied with constant nozzle diameter. Thin foil technique is used to estimate local heat transfer characteristics using IR thermal infrared imaging technique. Nusselt number distribution is plotted for all the cases using information got from IR image. It is observed that at lower frequency rate and low Strouhal number heat, transfer rate is more effective. A novel hybrid method to improve heat transfer rate is introduced in this study using Pulse combined with swirl technique. This method involves introducing swirler of specified twist ratio into nozzle subjected to air pulse. Experiments show that this novel hybrid method improves heat transfer rate at all the above-mentioned conditions.