Investigation of the Flow at the Exit of an Unshrouded Centrifugal Impeller and Comparison With the “Classical” Jet-Wake Theory

Rohne, K.-H.; Banzhaf, Matthias

doi:10.1115/90-gt-124

Cited by 7 publications

(11 citation statements)

References 1 publication

(6 reference statements)

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“…A relatively high entropy region (wake region) resides near the suction side for the near stall flow rate and over the shroud/suction corner for the design and choke flow rates. The calculation verifies the first assumption, by Rohne and Banzhaf (1991). Table I).…”

Section: Review Of Jet-wake Modelsupporting

confidence: 49%

“…Rohne' s model with F,w 1.1 shows the best prediction of the wake absolute tangential velocity component with that of the three-dimensional calculation. Figure 14 shows that both models unusually over-predict the mass fraction in comparison with 0.15-0.25 for the original jetwake model and 0.13-0.14 for Rohne and Banzhaf (1991) Rohne(1991) u FIGURE 13 Comparison of jet-wake and mixed-out velocity vectors (with proposed input wake mass and area fraction): (a) jet-wake model from Japikse, and (b) jet-wake model from Rohne. Calculation with jet-wake-model jet-wake-model according to Japikse (1985) according to Rohne (1991 Reasonable pre-input of the secondary mass and the area fractions in the two jet-wake models are critical for the accurate performance prediction.…”

Section: Review Of Jet-wake Modelmentioning

confidence: 99%

“…The boundary of the two regimes does not physically exist; the model indicates only that there is an isentropic core flow and that all the non-isentropy of the flow concentrates in the secondary flow regime. However, Rohne and Banzhaf (1991) defined the wake zone where the local value of the meridional component of velocity is less than 90% (DFw=0.9) of the global mean value. Therefore the properties in the jet and wake zones in the two models are different from each other.…”

Section: Review Of Jet-wake Modelmentioning

confidence: 99%

“…Table I). When the predicted values of total temperature and total pressure at the impeller exit in the present three-dimensional calculation are used, the mass fraction and slip factor can be obtained using two models (0.564 for the original model and 0.16 for Rohne and Banzhaf (1991) model). Rohne' s model with F,w 1.1 shows the best prediction of the wake absolute tangential velocity component with that of the three-dimensional calculation.…”

Section: Review Of Jet-wake Modelmentioning

confidence: 99%

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Application of Through‐Flow Calculation to Designand Performance Prediction of Centrifugal Compressor

Choi

Kang

1998

International Journal of Rotating Machinery

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A computer code predicting the flows through the centrifugal compressor with the radial vaneless diffuser was developed and applied to investigate the detailed flowfields, i.e., secondary flows and jet-wake type flow pattern in design and off-design conditions. Various parameters such as slip factors, aerodynamic blockages, entropy generation and two-zone modeling which are widely used in design and performance prediction, were discussed.A control volume method based on a general curvilinear coordinate system was used to solve the time-averaged Navier-Stokes equations and SIMPLER algorithm was used to solve the pressure linked continuity equation. The standard k-e turbulence model was used to obtain the eddy viscosity. Performance of the code was verified using the measured data for the Eckardt impeller.

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Section: Review Of Jet-wake Modelsupporting

confidence: 49%

Section: Review Of Jet-wake Modelmentioning

confidence: 99%

Section: Review Of Jet-wake Modelmentioning

confidence: 99%

Section: Review Of Jet-wake Modelmentioning

confidence: 99%

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Application of Through‐Flow Calculation to Designand Performance Prediction of Centrifugal Compressor

Choi

Kang

1998

International Journal of Rotating Machinery

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“…Eckardt's laser anemometer measurements in a radial outflow impeller provided the first experimental evidence in high-speed impellers of the development of a "wake" of low-momentum fluid near the suction surface/ shroud corner of the blade passage (Eckardt, 1976). Krain (1988), Krain and Hoffman (1990), Ahmed and Elder (1990), Sipos (1991), and Rohne and Banzhaf (1990) acquired laser anemometer measurements in backswept impellers which indicate that the wake develops near the shroud at midpitch.…”

Section: Introductionmentioning

confidence: 99%

Experimental and Computational Investigation of the NASA Low-Speed Centrifugal Compressor Flow Field

Hathaway

Chriss

Wood

et al. 1993

Journal of Turbomachinery

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An experimental and computational investigation of the NASA Low-Speed Centrifugal Compressor (LSCC) flow field has been conducted using laser anemometry and Dawes’ three dimensional viscous code. The experimental configuration consists of a backswept impeller followed by a vaneless diffuser. Measurements of the three-dimensional velocity field were acquired at several measurement planes through the compressor. The measurements describe both the throughflow and secondary velocity field along each measurement plane. In several cases the measurements provide details of the flow within the blade boundary layers. Insight into the complex flow physics within centrifugal compressors is provided by the computational analysis, and assessment of the CFD predictions is provided by comparison with the measurements. Five-hole probe and hot-wire surveys at the inlet and exit to the rotor as well as surface flow visualization along the impeller blade surfaces provide independent confirmation of the laser measurement technique. The results clearly document the development of the throughflow velocity wake, which is characteristic of unshrouded centrifugal compressors.

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Effects of Manufacturing Noise on Microturbine Centrifugal Impeller Performance

Javed

Pečnik

Olivero

et al. 2012

Journal of Engineering for Gas Turbines and Power

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This paper presents a study on a small centrifugal impeller for microturbine application from a manufacturing perspective. The aim is to analyze the impact of geometric deviations on part performance using adequate performance modeling tools and statistical methods. A one-dimensional (ID) performance analysis tool was developed in-house derived from the meanline and two-zone modeling methods. The ID model proved to be a simple and computationally inexpensive tool for having a quick performance analysis of the impeller using basic geometric information extracted from part drawings. For the sensitivity analysis, a total of eight input geometric parameters, including radii, tip-clearance, and blade angles, were varied individually within specific limits in the ID tool for classifying their influence on the output performance. Since the ID model is a simplifled version of a much more complex three-dimensional (3D) model, a commercial computational fluid dynamics (CFD) tool was used to provide a comparison with the ID model and scrutinize the effects of such deviations on the fluid behavior inside the impeller passage at a detailed level. For uncertainty quantiflcation, Monte Carlo simulation was performed using the ID model to assess the variability of overall impeller output performance to simultaneous random deviations in the input geometric parameters. The study is useful to evaluate the possibility of designing gas turbine parts for manufacturability and superior production cost-effectiveness.Ohjective. Small-scale turbomachinery experience low Reynolds number effects resulting in increased viscous losses, manufacturing difficulties, and large heat transfer between the hot and cold components. Performance is influenced by all the three factors mentioned above. Furthermore, these factors are themselves subjective to design of the components comprising the turbomachine module. Thus, it can be rightfully stated that component designs influence the aerothermodynamics and manufacturing tolerances of a turbomachine, consequently impacting the performance as illustrated in Fig. 1.Performance is primarily associated to the impeller in a centrifugal compressor [5]. Therefore, focus was given to the impeller only. Study carried out in this paper follows a special route where the performance sensitivity of an on hand centrifugal compressor impeller is scrutinized by employing selective deviations to the design using various analysis tools in order to understand the relationship between component geometry, module performance, and manufacturing tolerances. The main objectives of the study are, thus, to develop design expertise for small-scale centrifugal compressors and to study the impact of manufacturing noise on component and module performances. MethodologyA simple methodology was devised to carry out this complicated task because of the level of uncertainty owing to the Journal of Engineering for Gas Turbines and Power

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Investigation of the Flow at the Exit of an Unshrouded Centrifugal Impeller and Comparison With the “Classical” Jet-Wake Theory

Cited by 7 publications

References 1 publication

Application of Through‐Flow Calculation to Designand Performance Prediction of Centrifugal Compressor

Application of Through‐Flow Calculation to Designand Performance Prediction of Centrifugal Compressor

Experimental and Computational Investigation of the NASA Low-Speed Centrifugal Compressor Flow Field

Effects of Manufacturing Noise on Microturbine Centrifugal Impeller Performance

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