This article aims to investigate effects of different blockage positions and configurations on the film cooling characteristics, considering that droplets with various sizes are injected into the coolant flow. The main conclusions can be summarized as follows:
(1) When hole blockage occurs, the outlet area of the flow passage becomes smaller. This results in an increase of the coolant flow velocity, and there is a liftoff of the coolant flow from the wall surface. Moreover, the BR ¼ 37% case has lower lateral values of h (film cooling effectiveness) than the no blockage case, and values of the film cooling effectiveness significantly decreases with an increase of the blockage ratio.
(2) A smaller size of the droplets provides a higher evaporation rate. Although the 1 mm droplet case has a similar cooling
Today, an important aerodynamic and marine device, gas turbine engines are applied to many fields such as shipping industry, aviation aircraft, power plant, and many fields. Shorten all. performed an advanced energy analysis method to evaluate the performance of gas turbine engines of aviation aircraft. To achieve a higher thermal efficiency, the initial gas temperature has reached to 2000 K. In such a Turbine running condition, the safety problem of the gas turbines has drawn remarkable attention. Indicated that the cracking on the vane surface occurred at high thermal stress regions or avoiding such type of problems by the, film cooling technology used in turbine engines to prolong the service life of the turbine components.
As per LUTUM and JOHNSON experiment, it is found that the cooling performance was weaken by decreasing the ratio L/D of the cylindrical film hole it menace we have increase there L/D ratio the cooling performance will be increase .it found the based on the wind tunnel test. Zhuetal Investigated heat transfer characteristics for several hole configurations at various Reynolds numbers.The results showed that a stronger turbulence effect occurred downstream cylindrical holes than downstream discrete holes. Based on the large eddy simulations (LES) method, Rozati and Tafti evaluated the effect of blowing ratios on the cooling performance.They suggested that the diffusion of the coolant air was accelerated at a high blowing ratio, which results in decreasing adiabatic film cooling effectiveness.
They found that the cooling performance was weakened by decreasing the L/D ratio of the cylindrical film hole. Based on a wind tunnel test, Zhuetal. Investigated heat transfer characteristics for several hole configurations at various Reynolds numbers. The results showed that a stronger turbulence effect occurred downstream cylindrical holes than downstream discrete holes. Based on the large eddy simulations (LES) method, Rozati and Tafti evaluated the effect of blowing ratios on the cooling performance. They suggested that the diffusion of the coolant air was accelerated at a high blowing ratio, which results in decreasing adiabatic film cooling effectiveness. Based on the standard k-ε turbulence model, Islami and Jubran analyzed the cooling performance for various turbulence intensities of the mainstream. They indicated that the film cooling effectiveness for the trenched film hole was not sensitive to the turbulence intensity of the mainstream. Graef and Kleiser investigated the effect of a double-row cylindrical hole.