Kenichiro Takeishi

An Experimental Study of Heat Transfer and Film Cooling on Low Aspect Ratio Turbine Nozzles

The effects of the three-dimensional flow field on the heat transfer and the film cooling on the endwall, suction and pressure surface of an airfoil were studied using a low speed, fully annular, low aspect h/c=0.5 vane cascade.The predominant effects that the horseshoe vortex, secondary flow, and nozzle wake increases in the heat transfer and decreases in the film cooling on the suction vane surface and the endwall were clearly demonstrated. In addition, it was demonstrated that secondary flow has little effect on the pressure surface. Pertinent flow visualization of the flow passage was also carried out for better understanding of these complex phenomena. Heat transfer and film cooling on the fully annular vane passage surface is discussed.Copyright

Contribution of Heat Transfer to Turbine Blades and Vanes for High Temperature Industrial Gas Turbines Part 1: Film Cooling

Abstract: This paper deals with the contribution of heat transfer to increase the turbine inlet temperature of industrial gas turbines in order to attain efficient and environmentally benign engines. High efficiency film cooling, in the form of shaped film cooling and full coverage film cooling, is one of the most important cooling technologies. Corresponding heat transfer tests to optimize the film cooling effectiveness are shown and discussed in this first part of the contribution.

Characteristics of Various Film Cooling Jets Injected in a Conduit

Abstract: In the present study, film cooling characteristics by the jets through various easy‐to‐make straight holes and slots have been investigated. In this experiment, seven kinds of injection geometries were used. They were circular, rectangular, elliptic and oval holes and slots, respectively.

Film Cooling on a Gas Turbine Rotor Blade

The film cooling effectiveness on a low-speed stationary cascade and the rotating blade has been measured by using a heat-mass transfer analogy. The film cooling effectiveness on the suction surface of the rotating blade fits well with that on the stationary blade, but a low level of effectiveness appears on the pressure surface of the rotating blade. In this paper, typical film cooling data will be presented and film cooling on a rotating blade is discussed.Copyright

Investigation of the Heat Transfer in High Temperature Gas Turbine Vanes

The demand for higher efficiency, higher temperature industrial gas turbines used for the combined cycle plants has increased. The key technology of such high-temperature gas turbines with a turbine inlet temperature of 1300°C is the development of reliable air-cooled turbine vanes and blades. The life prediction of such air-cooled turbine vanes is strongly dependent on an accurate prediction of the metal temperature. The problem of temperature prediction is essentially one of obtaining the convective heat transfer boundary conditions on the external and internal surfaces of the vane. In this paper, typical heat transfer data which are indispensable for the analysis, are presented. Improvement of the temperature prediction accuracy within 25°C, the final goal, is sought by feeding the discrepancy between the cascade test and the analysis back into the fundamental heat transfer tests.Copyright

Contribution of Heat Transfer to Turbine Blades and Vanes for High Temperature Industrial Gas Turbines Part 2: Heat Transfer on Serpentine Flow Passage

Abstract: The improvement of the heat transfer coefficient of the 1st row blades in high temperature industrial gas turbines is one of the most important issues to ensure reliable performance of these components and to attain high thermal efficiency of the facility. This paper deals with the contribution of heat transfer to increase the turbine inlet temperature of such gas turbines in order to attain efficient and environmentally benign engines. Following the experiments described in Part 1, a set of trials was conducted to clarify the influence of the blades rotating motion on the heat transfer coefficient for internal serpentine flow passages with turbulence promoters. Test results are shown and discussed in this second part of the contribution.

Preliminary Experiments of Heat Flux on Catalytic Wall.

This paper describes laboratory experiments of effect of wall catalysis on aerodynamic heating in high- temperature gases. Heat fluxes on two kinds of catalytic material, stainless steel and alumina ceramic, were measured in an arc-heated wind tunnel. Stainless steel was considered as near fully catalytic material whereas alumina ceramic was selected as non-catalytic material. In order to investigate the effect of wall catalysis, heat fluxes were measured in three different arc-keated gases, argon, nitrogen and air. Measured results showed that the stainless steel to alumina ceramic heat flux ratios for air were 38% larger than those for argon and nitrogen. This implies that the recombination of oxygen atoms on the wall due to catalysis of wall material partly controls heat flux.