Local heat and mass transfer measurements for multi-layered impingement/effusion cooling: Effects of pin spacing on the impingement and effusion plate

Autor: Hyung Hee Cho, Eui Yeop Jung, Kyeong Hwan Ahn, Ki Young Hwang, Seon Ho Kim, Jun Su Park
Rok vydání: 2017
Předmět:
Zdroj: International Journal of Heat and Mass Transfer. 105:712-722
ISSN: 0017-9310
DOI: 10.1016/j.ijheatmasstransfer.2016.10.007
Popis: 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, s p / 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 s p / d = 6.0. Local Sherwood number distributions are affected by biased location of pins at s p / 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 s p / d ) resulted in superior performance. Comparison factor of s p / d = 2.0 and s p / d = 1.5 was on the 2.2.
Databáze: OpenAIRE
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