Performances of Centrifugal Compressor Impellers in Steady and Unsteady Flow Regimes Under Inlet Flow Distortions

Michelassi, Vittorio; Pazzi, Simone; Echtner, S.; Giangiacomo, P.; Martelli, Francesco; Giachi, Marco

doi:10.1115/2001-gt-0325

Cited by 5 publications

(5 citation statements)

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“…It serves the purpose of guiding the incoming radial flow into the axial direction. As has been shown and discussed in previous works, such as [14][15][16][17][18], a radial inlet can result in flow distortion in both the radial and circumferential directions.…”

Section: Introductionmentioning

confidence: 52%

The effects of radial inlet with splitters on the performance of variable inlet guide vanes in a centrifugal compressor stage

Tan

X²,

et al. 2011

Proceedings of the Institution of Mechanical Engineers, Part C:

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Variable inlet guide vanes (VIGVs) can regulate pressure ratio and mass flow at constant rotational speed in centrifugal compressors as a result of inducing a controlled prewhirl in front of impellers. Radial inlets and VIGVs are typical upstream components in front of the first-stage impellers in many industrial centrifugal compressors. However, previous investigations on VIGVs in centrifugal compressors were mostly conducted under the condition of axial inlets, and this study aims to focus on the effects of radial inlet on the VIGVs performance of a centrifugal compressor stage. The axial inlet stage model is compared with the radial inlet stage model with splitters using numerical flow simulation. The flow from the radial inlet was nonuniform in both circumferential and radial directions; thus, the VIGVs, the impeller, the vaneless diffuser, and the return vane channel are modelled with fully 360 passages. The three-dimensional (3D) flow field is numerically simulated at VIGVs setting angles ranging from À20 to 60 . The overall stage performance parameters are obtained by integrating the field quantities. Though the splitters are equipped in the radial inlet, the overall stage polytropic efficiency decreases by an average of 4 per cent and total pressure ratio decreases by an average of 3.3 per cent in comparison with the axial stage model. This can be attributed to the effect of both flow non-uniformity induced by radial inlet and flow loss in the radial inlet at different VIGV setting angles. The flow loss in the radial inlet with splitters is the main reason of the stage performance decrease compared with the flow non-uniformity. The simulation results show that the performance of VIGVs is degraded by its inlet flow distortions resulting from a radial inlet. The results in this study can be applied to centrifugal compressor design and optimization.

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Section: Introductionmentioning

confidence: 52%

The effects of radial inlet with splitters on the performance of variable inlet guide vanes in a centrifugal compressor stage

Tan

X²,

et al. 2011

Proceedings of the Institution of Mechanical Engineers, Part C:

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“…As a result, positive and negative incidences would alternately appear at the inlet of the blade passages, which could further increase the alternating load on the impeller blades, deteriorate the flow conditions in the downstream components and negatively affect the performance of the centrifugal compressor. 6,[29][30][31] The comparisons made in these figures indicate that there were some differences between the numerical simulation and the measurements on Section 4. Compared with the experimental results, the simulated total pressure and Mach number in the dotted ellipse were higher, and the range of the low-pressure and low-speed area was smaller.…”

Section: Detailed Flow Conditions On Experimental Sectionsmentioning

confidence: 91%

Flow measurement and simulation of a radial inlet for centrifugal compressor

Han

Mao

Tan³

et al. 2015

Proceedings of the Institution of Mechanical Engineers, Part A:

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This paper presents an experimental and numerical research on the internal flow of a typical radial inlet for centrifugal compressor. Detailed flow measurements were carried out with five-hole probes, consisting of 106 sampling holes and 2178 measuring points. Automatic calibrating and measuring systems, which made the probe calibrations, measurements and data acquisitions controlled by computer, were developed and used to accelerate the flow measurements. Since separations and vortices in the radial inlet were not able to be accurately measured by five-hole probes, numerical simulation was adopted to assist in the flow analysis of the radial inlet in the present study. The investigation indicated that there were five main flow separations and vortices in the present radial inlet. Four of them were generated in the plenum, making the plenum the primary cause of the flow loss and the major factor of the flow distortions in the radial inlet. The last flow separation was generated on the inlet side of the flange at the 90° turning and extended to the exit of the axial duct. Besides, the symmetrical tangential flows in the radial inlet made positive and negative yaw angles with absolute value up to over 15° distributed in the tangential direction of the radial inlet’s exit, which will probably increase the incidence loss in the blade passages and negatively affect the work capability of the impeller. Based on the flow analysis and discussions, preliminary suggestions are proposed to provide references for the improvements of radial inlet.

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“…Recent investigations focused on multi stage axial and centrifugal compressors (Peters and Fottner [8] experimental investigations of co-and counter-rotating inlet distortions on a 5-stage axial compressor of an aircraft gas turbine engine and Chen et al [9] on radial inlet distortion on compressor performance in 2-stage turbo charging system respectively). Computational fluid dynamics are extensively used to predict the performance axial and centrifugal compressors under different types of inlet distortions Sghaier et al [10] and Yao et al [11 and 12] on single and multistage high speed axial compressors and Michellasi et al [13] on centrifugal compressors. Li et al [14] carried out experimental investigation on a transonic axial flow compressor to improve the compressor under inlet distortion conditions by using partial casing treatment.…”

Section: Motivationmentioning

confidence: 99%

Effects of Stage Loading on Performance and Flow Field of a Centrifugal Compressor With Inlet Pressure Distortion

Sitaram,

Govardhan,

Murali

2023

joast

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The paper presents experimental results on the effects of inlet total pressure distortion on the performance and flow field of a centrifugal compressor. The total pressure at the inlet is artificially distorted by means of a perforated sheet, which is supported by a support mesh. A total of eleven configurations, including clean inlet configuration, are tested. Performance measurements and impeller inlet and exit flow studies at three flow coefficients, one near design flow coefficient, one below design flow coefficient and one above design flow coefficient, are carried out. The present paper presents and discusses results at the three flow coefficients and the effects of stage loading on the distortion effects are presented. A new parameter, Distortion Index (DI) is introduced. As DI increases, the mass averaged total pressure at exit stations decreases. Distortion sector angle of 60° having the lowest total pressure is found to be the critical sector for circumferential distortion configurations. As the Distortion Correlation parameter, DC (60) increases, the mass averaged total pressure for circumferential distortion configuration decreases, except in the case of low flow coefficient where the mass averaged total pressure is nearly constant. DC (60) also increases with sector angle. The static pressure normalized with static pressure for clean inlet decreases as the distortion sector angle is increased. Distortion attenuates the static pressure as the flow passes through the vaneless diffuser. The attenuation increases with the distortion sector angle.

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Performances of Centrifugal Compressor Impellers in Steady and Unsteady Flow Regimes Under Inlet Flow Distortions

Cited by 5 publications

References 0 publications

The effects of radial inlet with splitters on the performance of variable inlet guide vanes in a centrifugal compressor stage

The effects of radial inlet with splitters on the performance of variable inlet guide vanes in a centrifugal compressor stage

Flow measurement and simulation of a radial inlet for centrifugal compressor

Effects of Stage Loading on Performance and Flow Field of a Centrifugal Compressor With Inlet Pressure Distortion

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