Flow Phenomena in a Vaned Diffuser of a Centrifugal Stage

Dalbert, Peter; Gyarmathy, G.; Sebestyen, A.

doi:10.1115/93-gt-053

Cited by 9 publications

(5 citation statements)

References 8 publications

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“…Since the code and its procedures are well known, it does not seem necessary to describe details of the software here. Over the last years, different versions of the BTOB3D code have been used very successfully for a great variety of different in-house design applications of radial and axial turbomachines (Casey et al ,1992, Scherer and Dalbert, 1992, Dalbert et al, 1993aand 1993b. Most of the computations for this exercise were carried out on a Silicon Graphics Crimson with a RS 4000 processor.…”

Section: Codes Usedmentioning

confidence: 99%

Numerical Transonic Flow Field Predictions for NASA Compressor Rotor 37

Dalbert

Wiss

1995

Volume 1: Turbomachinery

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Flow field calculations of the NASA transonic axial compressor Rotor 37 are presented. These were obtained by the two commercially available 3D Navier Stokes-codes BTOB3D and TASCflow using different turbulence models, i.e. Baldwin-Lomax and k -E. Some of the results were submitted to the CFD code assessment exercise organized in 1994 by the Turbomachinery Committee of the ASME, where a number of "blind" CFD predictions were compared against previously unknown experimental data taken at the NASA Lewis Research Center. The objective of these calculations was to use the codes in the same way as they are generally used by experienced engineers for standard industrial design tasks. Thus, the effort involved in grid generation, flow simulation runs and postprocessing was subject to the usual limitations in computer resources as well as a stringent observation of cost-effectiveness (manpower and time available). With both codes, two sets of calculations were carried out: BTOB3D with two different tip clearances and TASCflow with a uniform and a spanwise varying outlet static pressure. Generally, the results of both codes show good agreement with respect to the measured overall performance characteristics and averaged spanwise distributions. In particular, the TASCflow solutions display high prediction accuracy in some local details of the flow field while in the BTOB3D code, boundary effects seem to mix out the flow significantly.The solution strategies employed as well as the reasons for certain discrepancies between computations and measurements are discussed. NOMENCLATUREfi massflow rhmax maximum measured massflow p pressure z axial coordinate Indices choke calculated choking conditions in inlet out outlet total conditions

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Section: Codes Usedmentioning

confidence: 99%

Numerical Transonic Flow Field Predictions for NASA Compressor Rotor 37

Dalbert

Wiss

1995

Volume 1: Turbomachinery

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“…Eckardt, 1976, Casey et al, 1990, Krain, 1981. These data are used by designers and scientists to check their design philosophy and/or to validate their CFD codes (Casey et al, 1990, Dalbert et al, 1993, Howard et al, 1994, Moore and Moore, 1990, Dawes, 1994, Hah and Krain, 1990. But only a few detailed experimental data have been published for high pressure ratio centrifugal compressors running with transonic rotor and/or diffuser inlet flow (Pak, Krain andHoffmann, 1992, Colantuoni andColella, 1992).…”

Section: Introductionmentioning

confidence: 99%

Aerodynamics of a Centrifugal Compressor Impeller With Transonic Inlet Conditions

Krain¹,

Hoffmann²,

Pak³

1995

Volume 1: Turbomachinery

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“…Accurate flow measurements in high speed machines with narrow flow channels are very time-consuming, and certain areas of the flow path cannot be easily accessed with the laser beam. With the recent progress of numerical techniques applied to centrifugal compressors and transonic flow fields (Moore and Moore [1981], Hah and Krain [1990], Dawes [1991], Dalbert et al [1993], Dunham [1998], etc. ), CFD codes are routinely used during the design process.…”

Section: State Pressure Taps Along Shroud Contourmentioning

confidence: 99%

Analysis of Transonic Flow Fields Inside a High Pressure Ratio Centrifugal Compressor at Design and Off Design Conditions

Hah

Krain²

1999

Volume 1: Aircraft Engine; Marine; Turbomachinery; Microturbines and Small Turbomachinery

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This paper reports on an experimental and numerical study of detailed flow structures in a transonic centrifugal compressor impeller at various operating conditions. Experimental data were obtained from conventional and laser-two-focus measurements inside the impeller. Numerical results were obtained from steady, three-dimensional Reynolds-averaged Navier-Stokes calculations. Both the experimental data and the numerical solutions at the design condition indicate that the flow incidence is high near the hub and flow separation exists near the leading edge. Due to the flow separation, low momentum fluid migrates rapidly to the tip area resulting in further loss generation through increased shock/boundary layer interaction. At a higher flow rate, a second passage shock develops near the leading edge of the splitter blade, further increasing shock/boundary layer interaction. Numerical studies were performed to explore possible design modifications for better efficiency and higher pressure rise. First, the blade camber near the leading edge was modified to improve the incidence. Second, the blade thickness was reduced by 50 percent. The incidence modification eliminates the flow separation near the leading edge and makes a more uniform flow split between the two channels, resulting in better flow distribution at the impeller exit. The simulated blade thickness reduction, along with the modified incidence, improves the efficiency by about 5 percent and increases the impeller pressure rise from 6.1:1 to 7.1:1.

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Flow Phenomena in a Vaned Diffuser of a Centrifugal Stage

Cited by 9 publications

References 8 publications

Numerical Transonic Flow Field Predictions for NASA Compressor Rotor 37

Numerical Transonic Flow Field Predictions for NASA Compressor Rotor 37

Aerodynamics of a Centrifugal Compressor Impeller With Transonic Inlet Conditions

Analysis of Transonic Flow Fields Inside a High Pressure Ratio Centrifugal Compressor at Design and Off Design Conditions

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