Transactions of the Korean Society of Mechanical Engineers B (대한기계학회논문집B)

The Korean Society of Mechanical Engineers (대한기계학회)
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Effect of Pulsations on Flow and Heat Transfer Characteristics of an Impinging Jet

충돌제트의 유동 및 열전달 특성에 미치는 맥동의 영향

  • Published : 2001.12.01
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Abstract

Experiments are carried out to investigate the effect of pulsations on the flow and heat transfer characteristics of an axisymmetric impinging jet on a flat plate heated by using a gold coated aim. Vertex motion in the impinging jet is visualized using a fog generator, and a thermochromatic liquid crystal (TLC) technique is used to measure the time averaged local temperature distributions on the impingement plate. In addition, the quantitative data for mean velocity and turbulence intensity are obtained employing hot-wire anemometer. Parameters such as pulsating frequency (f = 0, 10 and 20 Hz) and the nozzle-to-palate spacing (H/D = 2, 10) are considered at the jet Reynolds number of 20,000. Consequently, the significant changes of flow structure and local Nusselt number distribution due to pulsations are observed. In the case of H/D = 2, the enhanced heat transfer coefficient exceeding 30 % is observed at the stagnation point. At the high H/D, heat transfer rate increases with pulsation frequency.

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References

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