Analysis Of Unsteady Characteristics In Turbine

The development trents of higher thrust-weight ratio and lower specific fuel consumption in aero-engine put a further demand on the design of gas turbine,which requires higher aerodynamic efficiency and more effective cooling measures.It is known that the flow in turbomachines is inherently unsteady due to the relative motion of adjacent blade rows.As a result,different scales of unsteady flow interacts in the passage. An in-depth understanding of the unsteady interaction process and its phasical mechanism is crucial to the design and improvement of advanced turbine.All the investigations in this thesis were conducted in the basic of in-house CFD software NUAA-Turbo,meanwhile much effort was also took in the optimization and improvement of 3D unsteady calculation methods.The work herein is list as follows.Firstly, in order to validate the engineering applicability and reliability of NUAA-Turbo,the steady simulations were carried out on PW-E3 single-stage high pressure turbine and the turbine components of 2F turbo-shaft engine respectively.The general performance parameters as well as the blades pressure distributions and flow angle characters were correctly consistent with experiment results.Secondly, the compute method of tip leakage flow was added into the sotfware.Based on the simulation of GE-E3 two-stage high pressure turbine,the typical tip leakage flow character and its effects on turbine were deeply analyzed.Thereafter,further investigations were emphasized on the unsteady interaction between the upper stator wake and the downstream rotor passage vortex and tip clearance vortex.Finally, the approximate computation method on the interface was used to carry out the 3D unsteady simulation on PW-E3 single-stage high pressure turbine in order to evaluate the effects of inlet temperature distortion.The unsteady attenuation and migration process of hot-streak in turbine passage were well captured. According to the comparation between simulation results of uniform and non-uniform incoming flow,the influence of hot-streak on aerodynamic parameters as well as heat transfer characters were studied.