Heat transfer at multiple-intermittent impacts of a hollow cone spray

The present work is aimed at quantifying the effects of frequency in the heat transfer at multiple-intermittent impacts of a hollow cone spray in a way to contribute to the development of advanced heat transfer techniques. The flow configuration is that of a spray impacting perpendicularly onto an aluminium flat plate located at 55 mm. The experiments are conducted at prescribed temperatures ranging from local nucleate/boiling to local transition regimes of heat transfer and with frequencies of injection from 10 Hz to 30 Hz with durations of 5 ms. Analysis is based on spatial resolved measurements of the instantaneous surface temperature during the period of injection, processed in order to obtain estimates of the instantaneous heat flux.〈q˙″¯〉m˙f(hfg)b·Aimpact-1=0.17·TwTf·(Δtinj·finj)-0.284(Δtinj·finj)+0.046·TwTf1-0.112TwTf-0.077.