Research On Design Technology Of High Pressure Turbine For Adaptive Cycle Engine

Adaptive cycle engine can meet the contradictory requirements,which is high thrust and low fuel consumption.At present,the research on the high-pressure turbine of the adaptive cycle engine has not formed a complete system,and its design theory is not a simple reference to the conventional turbine.Therefore,the research on the characteristics and design technology of the adaptive cycle engine's high pressure turbine is of great significance.Based on Pratt & Whitney E3 single-stage high-load turbine,the flow characteristics of the turbine under different working modes of the adaptive cycle engine are analyzed by means of numerical simulation,and the design technology of the convergent-divergent blade profile is discussed.Finally,it is applied to turbine's dimensional design and makes the turbine works efficiently in a wider range.1.Because high pressure turbine blade has wide operating range,this leads to a large variation of the attack angle and the relative Mach number.In the range of Mach number between 1.2 and 1.5,the influence of different ratio of convergent-divergent on the performance of the cascade and the internal flow is compared.The results show that although the expansion of air low is small in the cascade with small convergent-divergent ratio,air flow can be further expanded by the expansion channel formed by the wake and the suction surface to achieve the high exit Mach number.It is considered that the flow loss in cascade is much more sensitive to the convergent-divergent ratio when the exit Mach number is low.The results show that when the convergent-divergent ratio chose the theoretical design value of the low Mach number,which can make the cascade's whole aerodynamic performance is relatively good.2.The key technical requirements of the high-pressure turbine of the adaptive cycle engine under the current technological level are obtained,and the key design techniques of the high-pressure turbine for the development of the adaptive cycle engine are summarized in this paper..3.Based on Pratt & Whitney E3 high-pressure turbine,the characteristics of high-pressure turbine flow in adaptive cycle engine are studied.Combined with variable flow condition,the performance,structure and loss of turbines under different working modes are analyzed.The results show that to design a wide working range of single stage high load transonic turbine,mainly weakens turbine's shock loss and mixing loss in the small bypass ratio mode,then take into account the aerodynamic performance of turbine in the high bypass ratio mode.The large negative attack angle has a great influence on the flow field structure of the high pressure turbine rotor,but has little effect on the aerodynamic performance of the rotor4.In this paper,the distribution law of the radial convergent-divergent ratio for a transonic turbine with a wide working range is studied.Firstly,the performance,flow characteristics and loss components of the turbine are analyzed.The accuracy of the two-dimensional design theory is verified.Secondly,the optimal scheme of the convergent-divergent ratio along the radial direction is studied.The results show that it is necessary to select the reasonable convergent-divergent ratio at the blade midsection to reduce intensity of trailing edge shock wave,and increase the convergent-divergent ratio at the top of the blade to weaken the mixing loss caused by the interaction between the shock wave and the leakage flow.When convergent divergent ratio increase along radial direction,the aerodynamic performance of the turbine in different operating modes is good.