Physics of hot crossflow ingestion in film cooling

Journal Article · Thu Jul 01 04:00:00 EDT 1999 · Journal of Turbomachinery

DOI:https://doi.org/10.1115/1.2841348· OSTI ID:679295

McGrath, E L; Leylek, J H ^[1]

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1. Clemson Univ., SC (United States). Dept. of Mechanical Engineering

Computational fluid dynamics (CFD) is used to isolate the flow physics responsible for hot crossflow ingestion, a phenomenon that can cause failure of a film cooled gas turbine component. In the gas turbine industry, new compound-angle shaped hole (CASH) geometries are currently being developed to decrease the heat transfer coefficient and increase the adiabatic effectiveness on film cooled surfaces. These new CASH geometries can have unexpected flow patterns that result in hot crossflow ingestion at the film hole. This investigation examines a 15 deg forward-diffused film hole injected streamwise at 35 deg with a compound angle of 60 deg (FDIFF60) and with a length-to-diameter ratio(L/D) of 4.0. Qualitative and quantitative aspects of computed results agreed well with measurements, thus lending credibility to predictions. The FDIFF60 configuration is a good representative of a typical CASH geometry, and produces flow mechanisms that are characteristic of CASH film cooling. FDIFF60 has been shown to have impressive downstream film cooling performance, while simultaneously having undesirable ingestion at the film hole. In addition to identifying the physical mechanisms driving ingestion, this paper documents the effects on ingestion of the blowing ratio, the density ratio, and the film hole Reynolds number over realistic gas turbine ranges of 0.5 to 1.88, 1.6 to 2.0, and 17,350 to 70,000, respectively. The results of this study show that hot crossflow ingestion is caused by a combination of coolant blockage at the film hole exit plane and of crossflow boundary layer vorticity that has been re-oriented streamwise by the presence of jetting coolant.

• Sponsoring Organization: USDOE
• OSTI ID: 679295
• Report Number(s): CONF-980615--
• Journal Information: Journal of Turbomachinery, Journal Name: Journal of Turbomachinery Journal Issue: 3 Vol. 121; ISSN JOTUEI; ISSN 0889-504X
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
COMPUTERIZED SIMULATION
CROSSFLOW SYSTEMS
FILM COOLING
FLOW MODELS
PERFORMANCE
TURBINE BLADES