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Affiliation of Author(s):能源与动力学院

Journal:Exp. Therm. Fluid Sci.

Abstract:An experimental research is performed to illustrate the effects of the transmission pipe and nozzle exit shape on the synthetic jet impingement heat transfer, by using a piston-driven actuator. Three transmission pipes (namely short pipe, moderate pipe and long pipe) and two nozzle exit shapes (round and chevron) are taken into considerations. The experimental tests are conducted at five operational frequencies (f = 5 Hz, 10 Hz, 15 Hz, 20 Hz and 25 Hz) and four dimensionless jet-to-surface distances (H/d = 2, 4, 6 and 8). The results show that the heat transfer around the jet stagnation is generally decreased by the long-pipe nozzle in comparison with the orifice-nozzle case, especially at higher operational frequencies. However, at a high operational frequency and a small jet-to-surface distance, of particular interest is that the short-pipe nozzle could improve the synthetic jet impingement heat transfer when compared to the orifice-nozzle case. The chevron nozzle is confirmed to be benefit for the synthetic jet heat transfer enhancement. Its role behaves distinctly at different jet-to-surface distances and operational frequencies. At low operational frequencies, the favorable jet-to-surface distance for the synthetic jet impingement heat transfer is altered due to the presence of the chevron exit when compared to the round-exit nozzle. While at larger operational frequencies, the relationships of the circumferentially-averaged Nusselt number varying with the jet-to-surface distance in the round synthetic jet impingement remain in the chevron synthetic jet impingement. © 2019 Elsevier Inc.

ISSN No.:0894-1777

Translation or Not:no

Date of Publication:2019-06-01

Co-author:Lyu, Yuan-wei,Liu, Xi-chen,TAN Xiaoming

Correspondence Author:zjz