Effects of vortex generators and pulsation on compound angle film cooling

Abstract

Compound angle film cooling is widely applied in modern turbine engines to provide reliable protection for the components. As passive and active methods, vortex generators enhance the thermal performance significantly, and pulsation coolant jet increases film cooling effectiveness when the compound angle is low. In the current study, the effects of vortex generators, pulsation, and their interactions have been investigated in film cooling with compound angles of 0 deg, 30 deg, and 60 deg. Cooling efficiency distribution is analyzed considering the coolant amount and separation condition. The downwash anticounter-rotating vortex pair (anti-CRVP) generated by vortex generators effectively increases film cooling effectiveness (FCE) in compound angle film cooling. Pulsation enhances the cooling performance by reducing the coolant separation when the lateral angle to the freestream is 0 deg; however, the performance is poor with 30 deg and 60 deg. Vortex generators are less efficient in enlarging the film coverage when pulsed jets are employed due to less coolant close to the surface. Moreover, mean and instantaneous vortex structures are illustrated to show the evolvements and interactions of the anti-CRVP, the counter-rotating vortex pair, the separated wakes, and the asymmetric vortex.