Viscous Three-Dimensional Simulation of Transonic Compressor Stage on Parallel Hardware

Abstract

The continued thrust toward more efe cient, economic, and lower-emission turbomachinery along with the reduced lead time available for design iterations and the high cost associated with extensive rig and engine tests keepspushing forwardthestateoftheart incomputationale uid dynamics. Thepaperstartsoffwitha discussion of the aeroengine development processand its timescales. The place and importanceof Navier -Stokesmethods in the development process are addressed, and the three-dimensional viscous codeemployed for aerodynamic design and analysisofturbomachinery atMotoren-und Turbinen-UnionMisintroduced. Abrieftreatmentofthecode is followed by a discussion of its implementation on parallel hardware architectures to reduce turnaround times for incorporation as an integral part of the design process; excellent performance on symmetric multiprocessing- parallelarchitecturesisdemonstrated.Thee rstthree-dimensionalviscoussimulationsandthee rstdetailedanalysis of thesingle-stagetransonic compressorrig attheTechnical University of Darmstadt, a research rig representative of modern high pressure compressor front stages, are presented. Computed results are compared to experimental data in terms of radial distributions derived from traverse data, in terms of rotor Mach number e elds derived from L2F data on S1 and S2 planes, and in terms of performance parameters critical to designers. The excellent agreementbetweensimulationsandexperimentsdemonstratesthecode' spredictivecapabilityforturbomachinery design. With qualitative and quantitativeagreement demonstrated, e owdetailsover the outer 40% span and in the tip region of the rotor are examined, based solely on computational results. Three-dimensional simulations with and without tip clearance are compared to two-and-one-half-dimensional simulations to separate the ine uence of tip leakage on the rotor blade Mach number e elds from other three-dimensional effects. The complex e ow near the tip, involving an interaction of casing boundary layer, blade boundary layer, shock systems, and tip, leakage e ow, is analyzed to further the understanding of highly loaded transonic compressors and to identify potential for performance improvements. The analysis explains the e ow features found in this research rig and identie es the mechanisms contributing to the rather high loss and blockage near the casing.