Practical implementation of transpiration cooling system can be realized by multi-layered impingement/effusion cooling system which is composed of two or more layers with pins. Due to restrictions of very low height in multi-layered impingement/effusion cooling, heat transfer characteristics are affected by pin space to diameter. In this paper, the effects of pin space to diameter ratio, sp/d, are investigated on all internal surfaces including impingement plate and pin surfaces. Local heat/mass transfer measured using a naphthalene sublimation method. The ratio of height to diameter ratio, h/d, is fixed at 0.25, and Reynolds number based on the hole diameter is 3000. As a results, heat transfer characteristics on effusion plate are similar to narrow impingement jet cooling without pins, in the case of sp/d = 6.0. Local Sherwood number distributions are affected by biased location of pins at sp/d = 2 and 1.5. Pins block the flow channel, and make flow area narrower. The secondary peak moved outwards in the radial direction, 18%, and Sherwood number of the secondary peak was enhanced by 6%. Comparing the heat/mass transfer of all of the cases, and considering pumping power, increasing pins (decreasing sp/d) resulted in superior performance. Comparison factor of sp/d = 2.0 and sp/d = 1.5 was on the 2.2.
|Number of pages||11|
|Journal||International Journal of Heat and Mass Transfer|
|Publication status||Published - 2017 Feb 1|
Bibliographical noteFunding Information:
This work was supported by the Human Resources Development program (No. 20144030200560) of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) Grant funded by the Korea government Ministry of Trade, Industry and Energy. The authors wish to acknowledge support for this study by the Agency for Defense Development.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Mechanical Engineering
- Fluid Flow and Transfer Processes