The influence of water mist injection on the film cooling process of casted turbine blades

Casted turbine blades are usually made of Ni- based super alloys, which are capable to withstand higher temperatures than other technical metal materials and have good corrosion resistance properties. The combustion efficiency highly depends on the temperature, but currently used turbine blades materials are not capable to withstand such conditions, therefore utilising the film cooling process is necessary. The influence of water mist injection on the film cooling process of casted turbine blades was numerically investigated. CFD simulations were performed to describe the interaction between the hot stream gas from the combustion chamber and the coolant jet from a cooling hole along with the water mist injection. The validation case with the cylindrical hole was compared to the experimental results and results from Large Eddy Simulation (LES) available in the literature. Temperature distributions were analysed and compared to the case with a laidback hole and console configuration to investigate the influence of injecting the water mist on cooling performance. The results showed the possibility of improving the film cooling performance by implementing the water mist injection system which allows the increase of the temperature in the combustion chamber, and consequently overall gas turbine efficiency.