Pressure-based Coupled Simulation of Pressure Recovery and Distortion in an S-shaped Intake Diffuser
Speaker: Konstantine Kourbatski, ANSYS Inc.
Presentation
Abstract
There has been a wide use of S-shaped inlets in military and commercial aircraft where design constraints require the engine to be buried into the fuselage. Other advantages of using S-shaped inlets include reduction in drag and pitching moment, and a more ergonomic inlet integration into the airframe which reduces the use of aircraft space and leaves more room for payloads and passengers. The flow inside an S-duct inlet is complicated because of its curved shape, and such flow complexity may introduce undesired losses into the system. The flow inside the S-duct turns and diffuses, creating pressure gradients in the streamwise and circumferential directions. These gradients cause the flow to separate and induce undesired secondary flows. Total pressure losses due to flow separation and distortion due to secondary flows negatively affect the compressor performance and may even lead to compressor stall.
The problem of a compressible flow through an S-shaped compact offset intake diffuser is studied computationally using the general purpose CFD code ANSYS Fluent. Steady-state converged solutions are calculated using second-order upwind discretizations. A hierarchy of several computational meshes is applied to evaluate grid independence. The near-wall resolution in all four meshes is fine enough to resolve the viscosity-affected near-wall region all the way to the laminar sublayer. Performance of four turbulence RANS models are compared: Spalart-Allmaras, SST k-w, Realizable k-e, and Reynolds Stress model with low-Re stress-omega formulation of the pressure-strain term. Numerical predictions of total pressure recovery and pressure distortion are compared with the experimental data. An excellent agreement is presented for pressure recovery, and favorable agreement is found in the prediction of distortion. An effect of vortex generator vanes on pressure recovery and distortion is also studied. An additional configuration of the S-duct model incorporating test probes is considered to evaluate the effects of experimental instrumentation at the Aerodynamic Interface Plane (AIP) on predicting distortion.
Biography
Konstantine Kourbatski received his Ph.D. in Applied and Computational Mathematics in 1997 from Florida State University where he worked, as a graduate student and later as a post-doc, on Computational Aeroacoustics and aircraft noise problems. After completing his post-doctoral work, Konstantine joined Siemens Automotive in London, Ontario, Canada where he spearheaded Computational Aeroacoustics Program to improve acoustic properties of cooling modules and thermo-structures. Prior to joining Fluent Inc. in 2004 (which became a part of ANSYS, Inc. in 2006), Konstantine led the development of CFD and heat transfer models for industrial heat exchanger applications at Unifin International Inc. in London, Ontario. In his present capacity of a Lead Technical Services Engineer at ANSYS, Inc., Konstantine leads atechnical team of engineers focusing on providing technical support of ANSYS fluids simulation products to North American customers, developing new simulation technologies and collaborating with universities. Konstantine’s areas of research expertise and interests include: Compressible Flows and Aeroacoustics, Moving and deforming meshes, and Turbulence.