An experimental investigation to obtain detailed film cooling effectiveness distributions on a cooled turbine blade platform within a linear cascade has been completed. The Reynolds number of the freestream flow is 3.1×105, and the platform has a labyrinthlike seal upstream of the blades to model a realistic stator-rotor seal configuration. An additional coolant is supplied to the downstream half of the platform via discrete film cooling holes. The coolant flow rate through the upstream seal varies from 0.5% to 2.0% of the mainstream flow, while the blowing ratio of the coolant through the discrete holes varies from 0.5 to 2.0 (based on the mainstream velocity at the exit of the cascade). Detailed film cooling effectiveness distributions are obtained using the pressure sensitive paint (PSP) technique under a wide range of coolant flow conditions and various freestream turbulence levels (0.75% or 13.4%). The PSP technique clearly shows how adversely the coolant is affected by the passage induced flow. With only purge flow from the upstream seal, the coolant flow rate must exceed 1.5% of the mainstream flow in order to adequately cover the entire passage. However, if discrete film holes are used on the downstream half of the passage, the platform can be protected while using less coolant (i.e., the seal flow rate can be reduced).

Detailed film cooling effectiveness distributions were experimentally obtained on a turbine blade platform within a linear cascade. The film cooling effectiveness distributions were obtained on the platform with upstream disturbances used to simulate the passing vanes. Cylindrical rods, placed upstream of the blades, simulated the wake created by the trailing edge of the stator vanes. The rods were placed at four locations to show how the film cooling effectiveness was affected relative to the vane location. In addition, delta wings were placed upstream of the blades to model the effect of the passage vortex (generated in the vane passage) on the platform film cooling effectiveness. The delta wings create a vortex similar to the passage vortex as it exits the upstream vane passage. The film cooling effectiveness was measured with the delta wings placed at four location, to investigate the effect of the passing vanes. Finally, the delta wings were coupled with the cylindrical rods to examine the combined effect of the upstream wake and passage vortex on the platform film cooling effectiveness. The detailed film cooling effectiveness distributions were obtained using pressure sensitive paint in the five blade linear cascade. An advanced labyrinth seal was placed upstream of the blades to simulate purge flow from a stator-rotor seal. The coolant flow rate varied from 0.5% to 2.0% of the mainstream flow, while the Reynolds number of the mainstream flow remained constant at 3.1×105 (based on the inlet velocity and chord length of the blade). The film cooling effectiveness was not significantly affected with the upstream rod. However, the vortex generated by the delta wings had a profound impact on the film cooling effectiveness. The vortex created more turbulent mixing within the blade passage, and the result is reduced film cooling effectiveness through the entire passage. When the vane induced secondary flow is included, the need for additional platform cooling becomes very obvious.

The redispersion factor of microbe-carrying particles, which is the ratio of the concentration of floor-derived microbes in room air to those on a floor surface, was determined, as was the percentage of floor-derived microbes in room air. These relationships were shown to vary according to conditions in the room. Equations were derived that allow these relationships to be calculated for a variety of room conditions, including air supply rates, levels of personnel activity, and the effect of gravitational deposition on microbe-carrying particles.

Temperature and flow rate of combustion gases and cooling stream are essential conditions for blade integrity in gas turbines. Since the combustion products pass directly to the first stage of blades high thermal stresses can develop, so the temperature field in the blade material must be controlled to avoid damage and/or reduction of blade useful life. This paper discusses an investigation on the influence of cooling airflow reduction on blade life. The flow rate reduction under consideration may be due to malfunctions of the compressor such like deposits or partial blockage in the blade ducts. It has been reported that air discharge from the compressor can be reduced up to 15% of the nominal rate due to deposits related with impurities contained in the environment. In this work an evaluation of the effect of reducing the cooling airflow rate on the temperature distribution on the blades surface is attempted. The flow stream that surrounds the blade together with the cooling airflow in the blade interior channels were characterized in the laboratory. Fields of temperature on the blade surface were obtained using the temperature sensitive paint technique, TSP. Thermocouple measurements were used for punctual temperatures as a reference. The results showed the regions of possible thermal stresses concentration as a function of cooling airflow rate variations. Additionally, the problem was resolved computationally in conjugate mode, considering both fluid streams external and internal plus heat conduction at the interior of the blade material. The computer model is used to simulate other conditions not addressed in the experiment. The paper discusses the comparison of numerical to experimental results and discusses the methodology for further work.

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