Large-eddy simulations are performed to analyze film cooling in supersonic combustion ramjets (Scramjets). The transonic film cooling flow is injected through a slot parallel to a Ma = 2.44 main stream with a fully turbulent boundary layer. The injection Mach number is Mai = 1.2 and adiabatic wall conditions are imposed. The cooling effectiveness is investigated for adverse and favorable pressu...

The impact of shock waves on supersonic cooling films is studied using large-eddy simulations (LES). A laminar cooling film is injected through a slot at a Mach number Mai = 1.8 into a fully turbulent boundary layer at a freestream Mach number Ma∞ = 2.44. The cooling film is disturbed by oblique shock waves at deflection angles of 5° and 8° at two downstream positions of the slot. At shock impi...

An experimental study of hydrodynamics of film cooling is performed by using a single longitudinal slot on a cylindrical model simulated to the leading edge of the gas turbine blade. The model is set up into the test section of an open-circuit induced flow wind tunnel which provides the main flow. The injected air, as a secondary film flow, produced from a high pressure compressor is considered...

The effect of film cooling slot exit area and shape is studied. Detailed heat transfer coefficient and film effectiveness measurements are obtained simultaneously using a single transient IR thermography technique. Two designs with a crescent shaped exit and a slot exit are considered. The results show that the crescent shaped exit provides significantly higher film cooling effectiveness than t...

Air film cooling has been successfully used to cool gas turbine hot sections for the last half century. A promising technology is proposed to enhance air film cooling with water mist injection. Numerical simulations have shown that injecting a small amount of water droplets into the cooling air improves film-cooling performance significantly. However, previous studies were conducted at conditio...

Effective cooling of gas turbine combustor liners, combustor transition pieces, turbine vanes (nozzles) and blades (buckets) is a critical task to protect these components from the flue gas at extremely high temperature. Air film cooling has been successfully used to cool these hot sections for the last half century. However, the net benefits from the traditional methods seem to be marginally i...

Cooling of gas turbine hot section components such as combustor liners, combustor transition pieces, turbine vanes (nozzles) and blades (buckets) is a critical task for improving the life and reliability of hotsection components. Conventional cooling techniques using air-film cooling, impingement jet cooling, and turbulators have significantly contributed to cooling enhancements in the past. Ho...

Numerical simulation is performed in this study to explore filmcooling enhancement by injecting mist into the cooling air with a focus on investigating the effect of various modeling schemes on the simulation results. The effect of turbulence models, dispersed-phase modeling, inclusion of different forces (Saffman, thermophoresis, and Brownian), trajectory tracking, and mist injection scheme is...