Design and Analysis of HP-Turbine for Variable Cycle Engine

A supersonic highly loaded high-pressure turbine with large enthalpy drop was designed for a variable cycle Engine (VCE) in the conditions of both single and double bypass modes in accordance with the similarity principle in the paper. The blade profiles were designed by means of a three-dimensional (3D) profile design method based on S₁ stream surface. Then, 3D numerical simulations were performed on the HP turbine of both working conditions with different thermodynamic cycle parameters to confirm the design methods and results. The one-equation turbulence model of Spalart-Allmaras was applied to solve Reynolds’s averaged Navier-Stokes equations and the transition model of Abu-Ghanam Shaw (AGS) was introduced to capture the development process of boundary layer on blade surfaces in the simulations. The results of simulations indicate that the turbine performances are satisfactory in both working conditions with high efficiency and the design targets being anticipated have been achieved. The method of design profiles based on S₁ stream surface is more precise and effective than conventional cylinder method for turbine blade because the 3D characteristics of flow field are considered elaborately. Further research reveals wave structures in the supersonic turbine, behavior of tip clearance flow, the phenomenon of transition flow in boundary layer and the physical mechanism of strong compressive wave-boundary layer interactions.