Investigation of detailed film cooling effectiveness and heat transfer distributions on a gas turbine airfoil
- Swiss Federal Inst. of Tech., Lausanne (Switzerland)
In the present study film cooling effectiveness and heat transfer were systematically investigated on a turbine NGV airfoil employing the transient liquid crystal technique and a multiple regression procedure. Tests were conducted in a linear cascade at exit Reynolds numbers of 0.52e6, 1.02e6 and 1.45e6 and exit Mach numbers of 0.33, 0.62 and 0.8, at two mainstream turbulence intensities of 5.5 and 10%. The film cooling geometry consisted of a single compound angle row on the pressure side (PS), and a single or a double row on the suction side (SS). Foreign gas injection was used to obtain a density ratio of approximately 1.65, while air injection yielded a density ratio of unity. Tests were conducted for blowing ratios of 0.25 to 2.3 on the SS, and 0.55 to 7.3 on the PS. In general film cooling injection into a laminar BL showed considerably higher effectiveness in the near-hole region, as compared to a turbulent BL. While mainstream turbulence had only a weak influence on SS cooling, higher effectiveness was noted on the PS at high turbulence due to increased lateral spreading of the coolant. Effects of mainstream Mach and Reynolds number were attributed to changes of the BL thickness and flow acceleration. Higher density coolant yielded higher effectiveness on both SS and PS, whereas heat transfer ratios were increased on the SS and decreased on the PS. Comparison of the single and double row cooling configurations on the SS revealed a better film cooling performance of the double row due to an improved film coverage and delayed jet separation.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 351619
- Report Number(s):
- CONF-980615-; ISSN 0889-504X; TRN: IM9927%%144
- Journal Information:
- Journal of Turbomachinery, Vol. 121, Issue 2; Conference: American Society of Mechanical Engineers (ASME) turbo expo `98 - land, sea, air, Stockholm (Sweden), 2-5 Jun 1998; Other Information: PBD: Apr 1999
- Country of Publication:
- United States
- Language:
- English
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