Pulsed Flow Jet Impingement Cooling: Evaluation of Heat Transfer Performance

Abstract

This thesis presents findings from an experimental and numerical investigation into merits of pulse coolant flow as an improvement to impingement cooling. A series of simulations were conducted at Re=12k and 30k for frequencies up to 20Hz and amplitude ratios up to 70% of mean mass flow and standoff and nozzle spacing equal to three diameters. Square waveforms were found to degrade at low frequencies near 1Hz, rendering the use of square waveforms as an invalid mass flow specifications for inlet boundaries in computational predictions. The Power Consumption Ratio is introduced for comparing pulse and steady flow configuration’s energy consumption. Pulse flow was found to decrease heat transfer efficiency for Re=12k, 30k which becomes more pronounced with increase in pulse configuration. Compressibility was shown to decrease the heat transfer efficiency the heat transfer efficiency for increased amplitudes for Re=30k.