Impingement cooling is one of the powerful cooling methods in high-temperature devices. For the gas turbine applications, impingement cooling is commonly applied in the transition piece of a combustor and in the leading edge, suction and pressure sides of a turbine blade/vane. In the suction side and pressure side, impingement cooling is applied as a form of an array jet. However, due to the small gap between the jet hole and target surface, the wall jet faces a crossflow inside of the gap. This crossflow has an adverse effect on the jets and deteriorates the heat/mass transfer performance. Therefore, several studies have been conducted to minimized the crossflow effect. The present study also investigated the effect of crossflow reduction in the gap by having a castellated hole plate. The heat/mass transfer was measured using the naphthalene sublimation method. Heat/mass transfer data are compared among three different cases. One is the baseline case which is simple array impinging jets. Others are the castellated cases with and without rib structures on the target wall. Jet-to-jet spacing(s/d) and jetto-target spacing(z/d) are selected as geometrical variables. Also, the experiments were conducted for the Reynolds numbers (based on jet hole diameter) of 5,000, 15,000 and 30,000. The baseline case was named as B case, the castellated case without rib structure as C case and with rib structure as CR case. Both C and CR cases showed the crossflow reduction effect and resulted high and similar Nusselt number values.
|Title of host publication||Heat Transfer - General Interest; Internal Air Systems; Internal Cooling|
|Publisher||American Society of Mechanical Engineers (ASME)|
|Publication status||Published - 2021|
|Event||ASME Turbo Expo 2021: Turbomachinery Technical Conference and Exposition, GT 2021 - Virtual, Online|
Duration: 2021 Jun 7 → 2021 Jun 11
|Name||Proceedings of the ASME Turbo Expo|
|Conference||ASME Turbo Expo 2021: Turbomachinery Technical Conference and Exposition, GT 2021|
|Period||21/6/7 → 21/6/11|
Bibliographical noteFunding Information:
This work was supported by the Human Resources Development program (No 20204030200110) of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government Ministry of Trade, Industry and Energy. Also, this work was supported by the Doosan Heavy Industries & Construction, Korea.
© 2021 by ASME.
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