Experimental investigations on showerhead cooling on a blunt body

Abstract

In modern gas turbines, the turbine airfoil leading edge is currently protected from the hot gases by specific film cooling schemes, socalled showerhead cooling. The present paper shows an experimental study of different showerhead cooling geometries on a blunt body. For these tests, TLC (thermochromatic liquid crystals) have been used for measuring the film cooling performance and the heat transfer. Detailed experimental results for the aerodynamics, the film cooling effectiveness and the heat transfer enhancement are presented for different film cooling geometries.

Coupling of internal and external cooling of gas turbine blades

“…In addition, the high heat transfer near the stagnation point is clearly visible; it can also be seen that the transition point moves upstream with increasing Reynolds numbers. The curves obtained of velocities and heat transfer coefficients are in agreement with the correlations of Falcoz [5].…”

“…So, when increasing the blowing ratio, the cooling effectiveness added by the internal cooling is more important than that lost from the external film cooling due to the lift off of the jet. The present work is a continuation of the investigations performed by Falcoz et al [5]. In this work, more global numerical computations are performed.…”

“…An influence of the blowing ratio is presented in the first step. Numerical results obtained for blowing ratios (G " 0.4, 0.6, 0.9, 1.2 and 1.4) are compared with experimental results of Falcoz [5]. The second step involves the Mach number study for cooled leading edge.…”

“…The result of overall cooling effectiveness will be compared with experimental measurement by Falcoz [5]. Before conduction heat transfer and film cooling results, it was necessary to characterize the aerodynamic flow field in the linear test facility, and to check the alignment of the model within the computational domain.…”

“…In this process a relatively cold air is injected from the interior to the exterior part to be cooled. Among many others, film cooling technique has been used for gas turbine blades for more than five decades [1][2][3][4][5][6][7][8][9]. However, the effectiveness of film cooling of gas turbine blades is very much dependent on the shape of the injection holes.…”