Effect of internal coolant crossflow on the effectiveness of shaped film-cooling holes

Conference · Thu Jul 01 04:00:00 EDT 1999

OSTI ID:20002436

Gritsch, M; Schulz, A; Wittig, S

Film-cooling was the subject of numerous studies during the past decades. However, the flow conditions on the entry side of the film-cooling hole have not received much attention up to now. A stagnant plenum which is widely used in experimental and numerical studies to feed the holes is not necessarily a right means to represent real engine conditions. For this reason, the present paper reports on an experimental study investigating the effect of a coolant crossflow feeding the holes that is oriented perpendicular to the hot gas flow direction to model a flow situation that is, for instance, of common use in the mid-portion of turbine blades. A comprehensive set of experiments was performed to evaluate the effect of perpendicular coolant supply direction on film-cooling effectiveness over a wide range of blowing ratios (M = 0.5{hor{underscore}ellipsis}2.0) and coolant crossflow Mach numbers (Ma{sub c} = 0{hor{underscore}ellipsis}0.6). The coolant to hot gas density ratio, however, was kept constant at 1.85 which can be assumed to be representative for typical gas turbine applications. Three different hole geometries, including a cylindrical hole as well as two holes with expanded exits, were considered. Particularly, two-dimensional distributions of local film-cooling effectiveness acquired by means of an infrared camera system were used to give detailed insight into the governing flow phenomena. The results of the present investigation show that there is a profound effect of how the coolant is supplied to the hole on the film-cooling performance in the near hole region. Therefore, crossflow at the hole entry side must be taken into account when modeling film-cooling at engine representative conditions.

• Research Organization: Univ. Karlsruhe (DE)
• OSTI ID: 20002436
• Report Number(s): CONF-990805--
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
COOLANTS
CROSSFLOW SYSTEMS
FILM COOLING
GAS TURBINE ENGINES
TURBINE BLADES