Effect of variable duty cycle flow pulsations on heat transfer enhancement for an impinging air jet

摘要

A series of experiments has been conducted in which a pulsed air jet is impinged upon a heated surface for the purpose of enhancing heat transfer relative to the corresponding steady air jet. Traditional variables such as jet to plate spacing, Reynolds number, and pulse frequency have been investigated. One additional flow variable-the duty cycle-representing the ration of pulse cycle on-time to total cycle time is introduced and shown to be significant in determining the level of heat transfer enhancement.