Effects of entrance crossflow directions to film cooling holes.
Two-dimensional distributions of local adiabatic film cooling effectiveness as well as discharge coefficients have been measured to investigate the effect of different entrance crossflow orientations and magnitudes on film-cooling performance. Operating conditions have been varied in terms of hot gas Mach number (up to 0.6), coolant crossflow Mach number (up to 0.6), coolant crossflow orientation (perpendicular or parallel with respect to the mainflow), and blowing ratio (0.5-1.5). The temperature ratio of coolant and hot gas was kept constant at 0.56 for the effectiveness tests, leading to an enginelike density ratio of 1.8. Infrared thermography was applied to perform local measurements of the surface temperatures with high resolution. The results indicate that the impact of hot gas crossflow Mach number is not very pronounced within the range of Mach numbers investigated. In contrast to this finding, the effect of internal coolant crossflow is very pronounced and strongly depends on coolant crossflow orientation and the ejected mass flow rate.
Saumweber
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Institut für Thermische Strömungsmaschinen Universität Karlsruhe, 76128 Karlsruhe, Germany.
Schulz
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Wittig
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Gritsch
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