Vorticity Dynamics Based Flow Diagnosis for a 1.5-Stage High Pressure Compressor With an Optimized Transonic Rotor

Abstract

This paper presents an optimized rotor as part of a 3-blade row optimization (IGV-rotor-stator) of a high-pressure compressor. It is based on modifying blade angles and advanced control of curvature of the airfoil camber line. The effects of these advanced blade techniques on the performance of the transonic 1.5-stage compressor were calculated using a 3D Navier-Stokes solver combined with a vortex/vorticity dynamics diagnosis method. The optimized rotor produces a 3-blade row efficiency improvement over the baseline of 1.45% while also improving stall margin. The throttling range of the compressor is expanded largely because the shock in the rotor tip area is further downstream than that in the baseline case at the operating point. Additionally, optimizing the 3-blade row block while only adjusting the rotor geometry ensures good matching of flow angles allowing the compressor to have more range. The flow diagnostics of the rotor blade based on vortex/vorticity dynamics indicate that the boundary-layer separation behind the shock are verified by on-wall signatures of vorticity and skin-friction vector lines. In addition, azimuthal vorticity and boundary vorticity flux (BVF) are shown to be two vital flow parameters of compressor aerodynamic performance that directly relate to the improved performance of the optimized transonic compressor blade.

Flow field behind a complex total pressure distortion screen

“…Further, these techniques were extended in Li et al 28 to account for three-dimensional viscous flow in axial compressor leading again to an improved rotor design. The recent study of Chen et al 29 also utilized x y as one of the two parameters to analyze the flow field through an optimized transonic rotor. These studies are for uniform inlet flows, and it remains to be seen how the non-uniform vorticity field is modified due to and through the compressor.…”

Improved Supersonic Turbulent Flow Characteristics Using Non-Linear Eddy Viscosity Relation in RANS and HPC-Enabled LES

“…Some researchers have attempted to characterize the turbulence in a tip-leakage flow of a single blade using non-linear RANS and zonal LES, as shown by Monier et al [24]. While Chen et al [25,26] demonstrated the vorticity dynamics-based flow diagnosis for a 1.5 stage high-pressure compressor using RANS simulations to improve compressor aerodynamic performance, Wu and Porté-Agel [27] presented the atmospheric turbulence effects on wind turbine wakes using LES. While these studies employed LES, Siddappaji [28] demonstrated TKE is equal to viscous dissipation using momentum, vorticity, and entropy transport through RANS simulations in adiabatic process with an in-house analysis framework.…”

Flow Diagnosis and Optimization Based on Vorticity Dynamics for Transonic Compressor/Fan Rotor

“…According to Newton's law, in a coordinate system tangential and normal to the streamline, the resulting equations are shown in Figure 1 (assuming inviscid flow) [22] [23]. The static pressure gradient normal to the streamline is balanced by the density times velocity squared divided by the streamline radius of curvature, R. It shows that it is vital to skillfully control streamline curvature in a design process, since pressure gradient of the fluid is influenced significantly by streamline curvature.…”