Simulation Experimental Study On The Heat Transfer Characteristics Of Lamilloy Leading Edge Of A Turbine Blade

A numerical investigation and an experimental study were carried out on the flow and heat transfer characteristics of lamilloy(a multilayered porous material)leading edge of a turbine blade.First of all,a great amount of numerical stimulations were carried out on the fluid flow and heat transfer characteristics of a real sized turbine blade which lamilloy cooling configuration in leading edge range according to the shape of the turbine blade and boundary conditions at design point,such as 3 types of gas path,3 types of pin-fins,2 axis modes of impingement hole.The results show that: total pressure loss coefficient of A1 type of gas path is less than A2 and A3;total pressure loss coefficient of different types of pin-fins is similar;total pressure loss coefficient of E axis mode of impingement hole is less than U.The heat transfer coefficient of A1 type of gas path is the lowest while A3 is the highest;The heat transfer coefficients of different types of pin-fins vary with different gas pathes and different axis modes of impingement hole.The heat transfer coefficient of E axis mode of impingement hole is less than U.For the cooling effectiveness of the leading edge of the blade,A1 type of gas path is higher than A2 and A3;different types of pin-fins is similar and U axis mode of impingement hole is higher than E.Sencondly,the effect of mean blowing ratio and temperature ratio to the fluid flow and heat transfer characteristics of the real sized turbine blade with lamilloy was also carried out by numerical stimulation.The results shows that the average heat transfer coefficient and cooling effectiveness increase when mean blowing ratio and temperature ratio increase.Third,the verfication experiments were conducted to the lamilloy turbine blade with 4 different structures.The result shows that cooling effectiveness of these four structure increases when mean blowing ratio increases,while it decreases when temperature ratio increases.Finally,another numerical investigation was carried out on the fluid flow and heat transfer characteristics at different mean blowing ratios of a three times enlarged turbine blade,which calculation was made on a simulation experimental condition with the same Reynolds number,but relatively lower pressure and temperature.The results shows that the flow characteristics of the two models are very close while the Nusselt number and cooling effectiveness of the two models are evidently different.Based upon the calculated data a correction method is proposed,by which the corrected Nusselt number and cooling effectiveness distribution in the leading edge area of the enlarged model at simulation experimental condition can generally represent that of the real sized model at real work condition.In addition,the fluid flow and heat transfer characteristics at different temperature ratios of enlarged turbine blade were also concerned.The heat transfer characteristics distribution of enlarged model is similar to that of the real sized model,but it shows significant difference in the value.