Aerodynamics of a Centrifugal Compressor Impeller With Transonic Inlet Conditions

Krain, H.; Hoffmann, B.; Pak, H.

doi:10.1115/95-gt-079

Cited by 43 publications

(47 citation statements)

References 16 publications

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“…The first reported measurements were obtained by Eckardt (1976) using a Laser-2-Focus Velocimeter. Since then, several other researchers ( Adler and Levy, 1979;Eckardt, 1979;Krain, 1981Krain, , 1987Ahmed and Elder, 1990;Pak et al, 1993;Krain et al, 1995) have used laser anemometers to measure the flow fields within high-speed centrifugal impellers configured with both vaned and vaneless diffusers. Hathaway et al (1993) reported results from a study in a large low-speed compressor.…”

Section: Introductionmentioning

confidence: 99%

Laser Anemometer Measurements of the Flow Field in a 4:1 Pressure Ratio Centrifugal Impeller

Skoch

Prahst²,

Wernet

et al. 1997

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

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A laser-doppler anemometer was used to obtain flow-field velocity measurements in a 4:1 pressure ratio, 4.54 kg/s (10 lbm/s), centrifugal impeller, with splitter blades and backsweep, which was configured with a vaneless diffuser. Measured through-flow velocities are reported for ten quasi-orthogonal survey planes at locations ranging from 1% to 99% of main blade chord. Measured through-flow velocities are compared to those predicted by a 3-D viscous steady flow analysis (Dawes) code.The measurements show the development and progression through the impeller and vaneless diffuser of a through-flow velocity deficit which results from the tip clearance flow and accumulation of low momentum fluid centrifuged from the blade and hub surfaces. Flow traces from the CFD analysis show the origin of this deficit which begins to grow in the inlet region of the impeller where it is first detected near the suction surface side of the passage. It then moves toward the pressure side of the channel, due to the movement of tip clearance flow across the impeller passage, where it is cut by the splitter blade leading edge. As blade loading increases toward the rear of the channel the deficit region is driven back toward the suction surface by the cross-passage pressure gradient. There is no evidence of a large wake region that might result from flow separation and the impeller efficiency is relatively high. The flow field in this impeller is quite similar to that documented previously by NASA Lewis in a large low-speed backswept impeller.

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Section: Introductionmentioning

confidence: 99%

Laser Anemometer Measurements of the Flow Field in a 4:1 Pressure Ratio Centrifugal Impeller

Skoch

Prahst²,

Wernet

et al. 1997

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

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show abstract

“…Its geometry specification has been given by Appl. Sci. 2017, 7, 1081 8 of 22 Eisenlohr et al [36] and its measurement results have been provided by Krain et al [37]. The compared pressure curves are at 60%, 70% and 80% of design speeds, where the operating pressure ratios are similar to the investigated case.…”

Section: Validationmentioning

confidence: 73%

“…To further validate the numerical method for predicting performances and detailed flow fields of impellers with vaneless diffusers, the open transonic centrifugal compressor SRV2-O has been investigated applying the same numerical method. Its geometry specification has been given by Eisenlohr et al [36] and its measurement results have been provided by Krain et al [37]. The compared pressure curves are at 60%, 70% and 80% of design speeds, where the operating pressure ratios are similar to the investigated case.…”

Section: Validationmentioning

confidence: 96%

Mechanisms of Sweep on the Performance of Transonic Centrifugal Compressor Impellers

Zheng

2017

Applied Sciences

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Featured Application: The mechanism for the optimal sweep angle of centrifugal compressors has been proposed, which benefits high-efficiency designs of centrifugal compressors for turbocharger and gas turbine engine applications.Abstract: Transonic centrifugal compressors with high performance are required in the oil and gas industries, modern gas turbine engines, and turbochargers. The sweep of the blades is one of the crucial features that have a significant influence on their performance. This paper numerically investigates mechanisms by which sweep affects the performance of a transonic impeller with twin splitters. Sweep is defined as scaling up or down the shroud chord, and the variation range of the sweep angle has been chosen from −25 to +25 • . In the current case, results show that the variation of choke mass flow rate, pressure ratio, and efficiency value is around 1%. If the centrifugal compressor has a higher pressure ratio or a higher front loading, the sweep effect on compressor performance will be even stronger. The essential aerodynamic effect of sweep is the spanwise redistribution of the front loading, resulting in effects on the shock structure, the tip leakage vortex, and the flow separation. On the shroud section, forward sweep restricts the front loading, the shock strength, and the tip leakage vortex, which reduces the loss near the casing. On the hub section, aft sweep suppresses the front loading and the flow separation, which reduces the loss near the hub. It is the delicate balance between controlling the loss near the hub and the loss near the casing that determines the optimal sweep angle design.

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“…The experimental data reported by Krain et al [22] used to validate the numerical model. Computational results of the compressor pressure ratio have been compared with the experimental data in Figure 5.…”

Section: Numerical Model Validationmentioning

confidence: 99%

Comparison of Cooling Different Parts in a High Pressure Ratio Centrifugal Compressor

Moosania

Zheng

2016

Applied Sciences

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Cooling in a centrifugal compressor can improve the performance and reduce the impeller temperature. In a centrifugal compressor, external walls can be cool down, which is known as the shell cooling. This method avoids undesirable effects induced by other cooling methods. Cooling can be applied on different external walls, such as the shroud, diffuser or the back plate. This paper focuses on seeking the most effective cooling place to increase the performance and reduce the impeller temperature. It is found that shroud cooling improves the compressor performance the most. Shroud cooling with 2400 W of cooling power increases the pressure ratio by 4.6% and efficiency by 1.49%. Each 500 W increase in the shroud cooling power, increases the efficiency by 0.3%. Diffuser cooling and back plate cooling have an identical effect on the polytropic efficiency. However, back plate cooling increases the pressure ratio more than diffuser cooling. Furthermore, only back plate cooling reduces the impeller temperature, and with 2400 W of cooling power, the impeller temperature reduces by 45 K.

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Aerodynamics of a Centrifugal Compressor Impeller With Transonic Inlet Conditions

Abstract: Performance and laser measurement results are presented for a transonic centrifugal compressor stage, equipped with a backswept rotor designed for 586 m/s tip speed and a mean relative inlet tip Mach number of 1.30. ft

Cited by 43 publications

References 16 publications

Laser Anemometer Measurements of the Flow Field in a 4:1 Pressure Ratio Centrifugal Impeller

Laser Anemometer Measurements of the Flow Field in a 4:1 Pressure Ratio Centrifugal Impeller

Mechanisms of Sweep on the Performance of Transonic Centrifugal Compressor Impellers

Comparison of Cooling Different Parts in a High Pressure Ratio Centrifugal Compressor

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