Research On Composite Cooling On The Leading Edge Of Turbine Blade

Advanced gas turbine blade cooling technology is favored as it protects blades so that inlet gas temperature can be significantly increased leading to higher specific work and thermal efficiency. The biggest challenge is the cooling of the leading edge of blade as this part has highest thermal load and complicated heat transfer and air flow. In order to obtain better understanding of characteristics of heat transfer and gas flow of the leading edge of blades under the combined cooling condition, both experimental and simulation are applied in this research.A test apparatus is built which simulates the actual condition of leading edge of blade when combined cooling technology is applied. The temperatures in the outer and inner of blade are tested to calculate the combined cooling effectiveness. The effects of Re in the main flow, blowing ratio and temperature ratio on the heat transfer are investigated systematically and qualitatively. Combined cooling effectiveness is regarded as one of the most essential parameters in evaluating the effectiveness of the cooling under various operation conditions.The simulation by using commercial software FLUENT is carried out to explore the mechanism of the heat transfer and gas flow of combined cooling on the leading edge of the blade. The results of simulation are compared with the corresponding measurements from experimental investigation. The simulation is in good quality to predict the effect of the operation parameters on the heat transfer and flow in the leading edge of blades.The results illustrate that blowing ratio is the most important factor affecting the cooling efficiency among of the operation parameters. The bigger the blowing ratio, the higher the cooling effectiveness is. Re in the main flow only has slight effect on cooling efficiency and in general the cooling effectiveness increases with the Re increasing. In addition, the cooling efficiency declines with the temperature ratio (Tg/Tc) increasing.