Effect of jet direction on heat/mass transfer of rotating impingement jet

• Published in: Applied thermal engineering 2009-10, Vol.29 (14), p.2914-2920
• Main Authors: Hong, Sung Kook, Lee, Dong Hyun, Cho, Hyung Hee
• Format: Article
• Language: English
• Subjects: Applied sciences; Coriolis force; Energy; Energy. Thermal use of fuels; Engines and turbines; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Gas turbine; Heat transfer; Impingement jet; Theoretical studies. Data and constants. Metering
• ISSN: 1359-4311
• DOI: 10.1016/j.applthermaleng.2009.02.014

The objective of this study is to investigate the heat/mass transfer characteristics on various impinging jets under rotating condition. Two cooling schemes related to impingement jet are considered; array impingement jet cooling and impingement/effusion cooling. The test duct rotates at Ro = 0.075 with two different jet orientations and the jet Reynolds number is fixed at 5000. Two H/ d configurations of 2.0 and 6.0 are conducted. The detailed heat/mass transfer coefficients on the target plate are measured by a naphthalene sublimation technique. The rotation changes the local heat/mass transfer characteristics due to the jet deflection and spreading phenomenon. For H/ d = 6.0, the jet is strongly deflected at the leading orientation, resulting in the significant decrease in heat/mass transfer. At the axial orientation, the momentum of jet core decreases slightly due to jet spreading into the radial direction and consequently, the value of stagnation peak is a little lower than that of the stationary case. However, reduction of heat/mass transfer due to rotation disappears at a low H/ d of 2.0. In the averaged Sh, the leading orientation with H/ d = 6.0 shows 35% lower value than that of the stationary case whereas the other rotating cases lead to a similar value of the stationary case.