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...

A Phase Doppler Particle Analyzer (PDPA) system is employed to measure the two-phase mist flow behavior including flow velocity field, droplet size distribution, droplet dynamics, and turbulence characteristics. Based on the droplet measurements made through PDPA, a projected profile describing how the air-mist coolant jet flow spreads and eventually blends into the hot main flow is proposed. T...

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...

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...

An experimental study was performed to measure surface Nusselt number and film cooling effectiveness on a film cooled first stage nozzle guide vane using a transient thin film gauge (TFG) technique. The information presented attempts to further characterize the performance of shaped hole film cooling by taking measurements on a row of shaped holes downstream of leading edge showerhead injection...

To achieve high thermal efficiency in modern gas turbines, the turbine-inlet temperature has to be increased. In response to such requisites and to prevent thermal failure of the components exposed to hot gas streams, the use of different cooling techniques, including film cooling, is essential. Finding an optimum film cooling design has become a challenge as it is influenced by a large number ...

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...