Numerical Simulation Of Influence On The Rotor Aerodynamic Performance Of The Rotor-stator Interaction

With the increasing demand for gas turbine performance,there is also a higher expectation for the optimized design of turbine aerodynamic performance.During the work of the turbine,the high speed rotation of the moving blade determines that its own motion must be highly unsteady.Rortor-stator interaction is a common phenomenon in this unsteady motion-The working temperature of the gas turbine is extremely high,so the first stage rotor and stator must be cooled to protect the blades.When using the film cooling method,the cooling fluid will affect the mainstream and rotor stream field.Therefore,in this papr,the numerical simulation is used to investigated the effect of the stator with film cooling structure on the stator wake and the aerodynamic performance of the downstream moving blades under the rotor-stator interaction,which provides a dreference for the optimal design of the turbine.Firstly,the first stage rotor of a certain type turbine without air film cooling is investigated,numerical simulation calculation using commercial software Fluent combined with k-ωturbulence model.According to the calculation results,the transport process of the stator wake at the interface of the rotor-stator and the change of the flow field of the rotor with time are analyzed.The analysis found that after rotor-stator interaction,the total pressure loss in the rotor channel was more serious on the suction surface and increased when the wake arrived.The aerodynamic loss caused by the secondary flow at the tip of the rotor is more than the leakage flow,and it is affected by the frequency of wake trailing shedding.Secondly,gas turbine with film cooling structure for stator is investigated,numerical simulation calculation using commercial software CFX combined with k-co turbulence model.According to the calculation results,the downstream transport process of the stator wake with a film cooling structure under and the change of the flow field in the rotor channel are studied.The results show that two wakes with similar structure but different vortex core area will be formed at the trailing edge of the cooling stator.When the two wakes move to the middle of the channel,they will have different movement trends in three dimensions.When the wake interferes with the leading edge horseshoe vortex on the pressure surface of the rotor,the wake will inhibit the horseshoe vortex toward the hub,and the corresponding horseshoe vortex will.accelerate the local speed of the wake to cause the wake branch.The wake branch will hit the suction surface of the adjacent rotor and cause aerodynamic loss on,its period is the same as the wake period.Finally,under the same conditions of the geometrical model,the differences between the influence of the stator with and without cooling structure on the wake and the aerodynamic performance of the rotors under rotor-stator interaction are compared and analyzed.The analysis found that the wake generated when the stator has cooling structure is wider than the stator without cooling structure,and the flow pattern is different.At the entrance of the rotor,the fluctuation of the internal pressure of the wake generated by the film cooling structure of the stator over time is larger than uncooling structure stator,but the pressure is relatively large,and the pressure loss to the mainstream is relatively low.In the rotor channel,the different wakes of the two different types of stators have different mixing processes in the interference process of the vortex,which is mainly manifested in the root of the trailing edge of the suction surface of the rotor.The wake generated by the stator without cooling structure has a stronger suppression effect on the horseshoe vortex in the pressure surface of the rotor leading edge than the wake with the cooling structure of the stator.As a result,the trailing edge of the rotor suction surface near the root produces different fluid flow structures,which further affects the aerodynamic loss at the outlet of the rotor.There is a significant difference between 0.3 and 0.6 times the height of the rotor blade.