An Experimental and Numerical Investigation of the Effect of Cooling Channel Crossflow on Film Cooling Performance

Abstract

This paper presents an experimental and numerical investigation into film cooling performance over a flat plate. As previous studies have shown, the flow situation at the entry-side of the cooling hole shows a notable effect on film cooling performance. The present investigation takes this into account feeding the cooling holes from an internal cooling channel and not from a stagnant plenum. High resolution heat transfer coefficient and adiabatic film cooling effectiveness distributions received from transient liquid crystal experiments are presented. The Reynolds numbers of the hot gas channel and the coolant crossflow feeding the holes are varied. Furthermore, the effects of 45° angled ribs, introduced into the cooling channel, are investigated. The experiments are performed at constant blowing, momentum and pressure ratios. Numerical calculations of the adiabatic film cooling effectiveness for selected configurations using FLUENT are presented. Comparison reveals the influence of coolant channel Reynolds number and the introduced ribs on the cooling hole flow pattern leading to a changed film cooling performance.

Effect of Orientation of Internal Turbulence Promoting Ribs on Flow Characteristics for Film Cooling

“…This study focuses on the influence of the rib orientation in the internal cooling passage on the external cooling characteristics along the blade outer surface. Kissel et al (10) experimented the difference of cooling performance between the smooth case and the ribbed case for internal passage. They also carried out numerical analyses to show that the ribbed case enlarged the separation bubble at the hole inlet and resulted in the change of flow conditions at the hole outlet.…”

Effects of Turbulence Promoters of Gas Turbine Blades on Film Cooling Performance

“…For example, there are reports on the effects of the density ratio (1) , the blowing angle (2) , and the geometry of injection holes (3) (4) for the film cooling while there are reports on the effects of geometry of turbulence promoters (5) (6) , the passage bend (7) , and the blade rotation (8) for the internal convection cooling. In contrast, studies on the combined effects of the film cooling and the internal convection cooling are rather scarce except for a few studies such as those of Gritsch et al (9) , Fawcett et al (10) Kissel et al (11) , and Sakai et al (12) . The authors showed that the film cooling characteristics are different between the case where the cooling air is supplied from the internal flow and the case where it is supplied from a stagnant plenum.…”

Effects of Crossflow in an Internal-Cooling Channel on Film Cooling of a Flat Plate Through Compound-Angle Holes

“…Their study also showed that internal crossflow improved the performance of cylindrical holes, but reduced the performance of shaped holes. Kissel et al [13] varied the coolant channel Re and found the heat transfer coefficient decreasing with increasing Re, while the adiabatic effectiveness is nearly unaffected. Saumweber and Schulz [14] studied internal crossflow oriented perpendicular to the mainstream and found, as [10] did, a single helical motion in the hole.…”

“…To date, no studies have looked at the consequence of internal crossflow on compound-angle film cooling holes. Also, there has been little effort to validate the CFD, the notable exception being [13], but they do not match the experimental data. The effect of turbulence model choice on film cooling, especially for complex geometries is not well understood.…”