Investigation On Film Cooling Performances On The Stator-roter Blade

With the rapid development of aviation gas turbine engines and the continuous improvement of thermal efficiency and thrust-to-weight ratio, the desired turbine gas inlet temperature rises progressively, which makes the working environment of turbine blades much harsher. Therefore, one of the most effective methods of solving this problem is to develop advanced cooling technology. Because of the influence of self-rotation and upstream stator vane wake, the flow and heat transfer characteristics of rotor blade are pretty complicated. In order to improve the reality application value of present research work, it is essential to carry out further unsteady research on complete stator and rotor.Based on the above background, the complete stator/rotor computational models were constructed in this article. The unsteady realizable-k-? turbulence model was adopted to conduct numerical simulations on the flow and heat transfer characteristics of film cooling. Firstly, the turbulence model was validated and rotor/stator blade grids were simulated under unsteady condition. The unsteady flow mechanism was analyzed as well. Then, without cooling air out of stator, the film cooling characteristics of turbine rotor were investigated. The flow and heat transfer characteristics of film cooling air at different typical positions(pressure surface, suction surface, leading edge) on different time, rotating speed and blowing ratios were explored. It can be found from simulated results that the position change of stagnation line at different time and rotation speed contributes to the variation of cooling air flow direction. Thus, the coverage area of leading-edge film is reallocated and the film cooling efficiency alters as well. Besides, the cooling air blowing ratio has certain influence on the cooling efficiency of the above three positions.Eventually, the film cooling characteristics of turbine rotor with cooling air out of stator were investigated. The effects stator trail film cooling flow on the flow and heat transfer characteristics of rotor leading edge were analyzed. Research results show that, in direct wake-affecting zone, the stator film cooling air could help reduce the cooling efficiency when rotor cooling air ratio is relatively low, while it demonstrates the opposite trend when rotor cooling air ratio is high. However, in none wake-affecting zone, the stator film cooling air could help improve the cooling efficiency when rotor cooling air ratio is relatively low, while the cooling efficiency has little change when the rotor cooling air ratio is high.