가열된 평판에서 원형 충돌제트의 열전달에 미치는 난류유동 특성의 영향 = Effect of turbulent flow characteristics on the heat transfer of round impinging jet on a heated flat surface

다국어 초록 (Multilingual Abstract)

An experimental study of jet impingement on the surface with linear temperature gradient is conducted with the presentation of the turbulent characteristics and the heat transfer rates measured when this jet impinges normal to a flat plate. The jet Reynolds number ranges from 10,000 to 70,000, the temperature gradient of the plate is 1.6～4.4 ℃ /cm and the dimensionless nozzle to plate distance(H/D) is from 4 to 12. The results show that the peak of heat transfer rate occurs at the stagnation point, and the heat transfer rate decreases as the radial distance from the stagnation point increases. A remarkable feature of the heat transfer rate is the existence of the second peak. This is due to the turbulent development of the wall jet. Maximum heat transfer rate occurs when the axial distance from the nozzle to nozzle diameter(H/D) is 6 or 8. It has been found that the heat transfer rate increases with increasing turbulent intensity. The numerical analysis using the CFD package FLUENT is executed to compare the experimental results and to find out whether the CFD package can be adopt for the design of impinging jet. CFD satisfactorily predicted performance of jet impingement.