사각 수분류에 의한 가열면상에서의 열전달 특성에 대한 실험적 연구 Experimental Study of Heat Transfer Characteristics on a Heated Flat Surface by Rectangular Water Jet
pp.1174-1184
Jet impingement heat transfer is a very effective technique for exchanging high heat fluxs between a heated plate and a fluid. The purpose of this study is to investigate the heat transfer characteristics of a rectangular free water jet normally or obliquely impinging onto a flat plate. The water jet issued from a rectangular slot nozzle with a cross section of 1.5mm⨉40mm. The mean velocities of nozzle exit were varied from 1.5m/s to 6.1m/s. The Reynolds number range based on the nozzle gap and the mean velocity was 2200∼8800. Various impingement angles between the vertical rectangular water jet and the inclined flat surface were investigated : 90˚, 70˚, 60˚ and 50˚ . The Nusselt number is high at the impingement line, and decreases with departures from it. The stagnation Nusselt numbers were compared to predictions of several correlations proposed by other researchers. The locations of the peak Nusselt numbers do not coincide with the geometric center of the rectangular jet on the surface.