Experimental and numerical study on configuration, shape, distance and angle of attack in film cooling implementing vortex generator

Abstract

The impact of vortex generator configuration, shape, angle of attack and distance between vortex generator and film cooling hole has been studied using both experimental and numerical methods for enhancing the gas turbine blade’s film cooling efficiency. Infrared (IR) thermography technique has been used for investigating the temperature field. In order to obtain the velocity field ANSYS FLUENT has been implemented. The diameter of the film cooling hole and the cross-flow velocity are used to calculate the Reynolds number, which is set at 2369. The blowing ratio of the jet to the cross-flow has been changed to 0.5, 1.0, and 1.5. Effect of CFU and common flow down configuration has been investigated. The angle of attack has been varied as 35° and 45°. It is observed that common flow down configuration of vortex generator performs better than Common Flow Up configuration. Common flow down configuration as well as lower distance between vortex generator and film cooling hole enhance the film cooling effectiveness due to generation of secondary longitudinal vortices which decrease the strength of the counter rotating vortex structures. Among all the shape (triangular, rectangular and trapezoidal) rectangular vortex generator performs better. Growths of shear layer vortices are modified due to the inclusion of vortex generator. Overall, Vortex Generator with common flow down configuration and 35° angle of attack performs better than Common Flow Up configuration due to generation of secondary longitudinal vortices which annihilates the counter rotating vortex structures due to having rotational tendency opposite to Counter rotating vortex pair.