Adiabatic wall effectiveness measurements of film-cooling holes with expanded exits

Journal Article · Wed Jul 01 04:00:00 EDT 1998 · Journal of Turbomachinery

DOI:https://doi.org/10.1115/1.2841752· OSTI ID:290031

Gritsch, M; Schulz, A; Wittig, S ^[1]

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1. Univ. Karlsruhe (Germany). Lehrstuhl und Inst. fuer Thermische Stroemungsmachinen

This paper presents detailed measurements of the film-cooling effectiveness for three single, scaled-up film-cooling hole geometries. The hole geometries investigated include a cylindrical hole and two holes with a diffuser-shaped exit portion (i.e., a fan-shaped and a laid-back fan-shaped hole). The flow conditions considered are the crossflow Mach number at the hole entrance side (up to 0.6), the crossflow Mach number at the hole exit side (up to 1.2), and the blowing ratio (up to 2). The coolant-to-mainflow temperature ratio is kept constant at 0.54. The measurements are performed by means of an infrared camera system, which provides a two-dimensional distribution of the film-cooling effectiveness in the near field of the cooling hole down to x/D = 10. As compared to the cylindrical hole, both expanded holes show significantly improved thermal protection of the surface downstream of the ejection location, particularly at high blowing ratios. The laidback fan-shaped hole provides a better lateral spreading of the ejected coolant than the fan-shaped hole, which leads to higher laterally averaged film-cooling effectiveness. Coolant passage cross-flow Mach number and orientation strongly affect the flowfield of the jet being ejected from the hole and, therefore, have an important impact on film-cooling performance.

• Sponsoring Organization: USDOE
• OSTI ID: 290031
• Report Number(s): CONF-970604--
• Journal Information: Journal of Turbomachinery, Journal Name: Journal of Turbomachinery Journal Issue: 3 Vol. 120; ISSN JOTUEI; ISSN 0889-504X
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
33 ADVANCED PROPULSION SYSTEMS
AUGMENTATION
FILM COOLING
ORIFICES
SHAPE
TURBINE BLADES