Numerical Investigation On Heat Transfer Of Air-cooled Turbine Blade Structure

In the development of aero gas turbine engine, turbine inlet temperature is being continuouslyincreased to meet the demand of engine performance, such as higher thermal efficiency andthrust-weight ratio. In order to satisfy the requirements, the development of advanced cooling tech-nologies is one of the key factors.When various cooling technologies is integrated into a turbine blade,the cooling air flow and heat transfer characteristics inside the air-cooled blade will become complex.So it is necessary to study the structurally-complete turbine blade.Based on this research background, three different cooling configurations for air-cooled turbineblade with smaller scale was designed and numerical studied using the commercial code FLUENT,the cooling configuration includs film cooling, impingement cooling, ribbed wall, pin-fins and corre-sponding serpentine internal cooling flow path. Results show that the rational organization of air flowcan indeed play a positive role to enhance the heat transfer capacity, which is bebifit for cooling airconsumption reduction and turbine inlet temperature increasment.Secondly, the commercial code FLUENT was used for three-dimensional conjugate heat transfersimulation to determine temperature distribution of an air-cooled blade with thermal barrier coatings(TBCs). The effect of thermal barrier coatings thickness on the temperature decreasing capacity forblade metal surface was analyzed, and the temperature distributions with or without considering ra-diation heat transfer was compared. The results show that with the increase of thermal barrier coatingthickness, the temperature of the turbine blade decreases and the uniformity increases; When consid-ering the radiation heat transfer,the temperature increase is much more obvious without thermal bar-rier coating protection;The protective effect of thermal barrier coatings greatly improved when con-sidering the radiation heat transfer,the maximum temperature drop increases97K when the thicknessof thermal barrier coatings is0.25mm,so the radiation heat transfer can not be ignored in the actualturbine blade study.Finally, the flow field and heat transfer of the two kinds of film hole (cylindrical film hole andthe convergence slot hole) on the suction face of turbine blade were experimentally and numericallystudied. The results show that: the two kinds of film holes have vortex on the contrary;compared withcylindrical film holes, convergence slot hole has significantly improved the cooling efficiency; Be-cause the two counter-rotating gas downstream of the membrane pore vortex in the opposite direction,the same position with the secondary flow vortex flow has been enhanced, while the other side wasweakened, so the two film holes have the contrary vortex trending; as blowing ratio increases, themomentum of cooling air increases and impacts by the mainstream secondary flows decreases.