Numerical and experimental investigation of a new film cooling geometry with high P/D ratio

Abstract

In order to improve the coolant surface coverage, in the past years new geometries have been proposed with higher lateral fan-shaped angle and/or greater inter-hole pitch distance (P/D). Unfortunately it is not possible to increase the fan angle or the pitch distance even further without inducing a coolant separation and a drop in the overall effectiveness.This study proposes an innovative design which improves the lateral coverage and reduces the jet lift off. The results have been validated by a combination of numerical and experimental analyses: the experimental work has been assessed on a flat plate using thermo chromic liquid crystals and the results have been confirmed numerically by the CFD with the same conditions. The CFD simulations have been carried out considering a stochastic distribution for the free stream Mach number and the coolant blowing ratio.The experimental and computational results show an increase in lateral averaged adiabatic effectiveness of +30% than the baseline until a distance downstream of 20 times the coolant diameter.

Mesh sensitivity of RANS simulations on film cooling flow

“…The authors' observed that the tilted stagnation line on the rotor leading edge moved from the pressure side to the suction side, and the instantaneous coolant streamlines shifted from the suction side to the pressure side with increasing rotational speed. The Reynolds-averaged Navier-Stokes equations closed by the k −ω SST turbulence model was used to investigate a film cooling geometry with high hole pitch to diameter ratio [21]. The experimental data was successfully reproduced using the CFD method.…”

Numerical optimization of triangular concave edge shaped ramp in film cooling

“…Montomoli vd. [20] fan-şekilli film soğutma deliği ile akış-üstü rampanın birlikte tasarımının FSE'ne etkisini incelemişlerdir. Yaptıkları çalışmada rampanın yanal yönle merkez çizgi boyunca yerel basınç farkı yarattığı ve bunun da jet akışkanın yanal yönde daha fazla yayılmasına yardımcı olduğunu belirtmişlerdir.…”

Numerical investigation of the flow field and heat transfer characteristics for upstream continuous and truncated ribs

“…Hammami et al 11 proposed a pyramidal slope structure based on the literature 10 and improved the coverage of the coolant on the wall. Montomoli et al 12 proposed a ramp structure that fits forward expansion holes and found that this structure can improve the spanwise average adiabatic film cooling efficiency of the forward expansion holes. Chen 13 experimentally studied an upstream ramp mounted on a row of film holes.…”