Effects of SDBD and DBD-VGs plasma actuations on film cooling effect at the plain wall surface downstream a cylindrical hole were numerically investigated based on the RANS solutions and linearized body force model. With the user defined functions, the plasma actuation forces were implemented into the CFD solver by introducing the source terms in momentum equations. With the experiment data and referenced numerical results, the reliabilities of linearized body force model and numerical methods were validated. At a range of dimensionless actuation strengths and frequencies, film cooling effectiveness on the wall surface and flow pattern developments downstream the cooling hole were analyzed and also compared with the plasma-off case. The results show that both SDBD and DBD-VGs plasma actuations are able to reduce development of kidney vortex pair downstream the cooling hole, thus significantly improving the film cooling effect on wall surface. The SDBD plasma actuation causes a larger streamwise velocity gradient near-wall than the plasma-off case, thus delaying the coolant flow lifting-off downstream the cooling hole. However, DBD-VGs plasma actuation intensifies the development of anti-kidney vortex pair, which weakens the development of kidney vortex pair and widens the coolant coverage on wall surface along lateral direction. As the actuation strength and frequency increase, the film cooling effectiveness on wall surface is increased along both streamwise and lateral directions. Compared with the plasma-off case, the area-averaged film cooling effectiveness for DBD-VGs plasma actuation is increased by 330.5% with dimensionless actuation frequency 2.5 and dimensionless actuation strength of 30, whereas the area-averaged film cooling effectiveness is only increased by 100.5% with frequency of 2.5 and strength of 60 for SDBD plasma actuation. With the same actuation parameters, a higher film cooling effect is achieved on the wall surface for DBD-VGs plasma actuation, and also, the coolant coverage along lateral direction is significantly improved by DBD-VGs plasma actuation, as compared against the SDBD cases.

Enhanced Film Cooling Effect Downstream a Cylindrical Hole Using Sdbd and Dbd-Vgs Plasma Actuations

Paper Proceedings: https://asmedigitalcollection.asme.org/GT/GT2021/volume/84898

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