The method of the gas-dynamic centrifugal compressor stage characteristics recalculation for variable rotor rotational speeds and the rotation angle of inlet guide vanes blades if the kinematic and dynamic similitude conditions are not met

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 pipeline and multistage centrifugal compressors. However, previous investigations on VIGVs in centrifugal compressors were mostly conducted under the condition of axial inlets, and present work aims to focus on the effects of radial inlet on the VIGVs performance of a centrifugal compressor stage. The axial inlet stage model was compared with the radial inlet stage model using numerical flow simulation. The flow from the radial inlet was nonuniform in both circumferential and radial direction, thus the VIGVs, the impeller, the vaneless diffuser, and the return vane channel were modeled with fully 360-deg passages. The three-dimensional flow field was numerically simulated with FINE™/Turbo at VIGVs setting angles range from −20° to +60°. The overall stage performance parameters were obtained by integrating the field quantities. The simulation results show that the performance of VIGVs was significantly degraded by its inlet flow distortions resulting from a radial inlet. The stage performance map indicates that the overall stage polytropic efficiency decreased by an average of 2.5% and total pressure ratio decreased by an average of 1% because of the flow distortions at different VIGVs setting angles, in comparison with the axial stage model.

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

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/0954406211407799 ◽

2011 ◽

Vol 225 (9) ◽

pp. 2089-2105 ◽

Cited By ~ 14

Author(s):

J Tan ◽

X Wang ◽

D Qi ◽

R Wang

Keyword(s):

Centrifugal Compressor ◽

Pressure Ratio ◽

Stage Model ◽

Compressor Stage ◽

Centrifugal Compressors ◽

Guide Vanes ◽

Centrifugal Compressor Stage ◽

Inlet Guide Vanes ◽

Flow Loss ◽

Stage Performance

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 non-uniform 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 - 20° 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 3.3per 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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Aerodynamic improvement of centrifugal compressor stage inlet guide vanes

Technical mechanics ◽

10.15407/itm2019.03.038 ◽

2019 ◽

Vol 2019 (3) ◽

pp. 38-44

Author(s):

Yu.A. Kvasha ◽

◽

N.A. Zinevych ◽

N.V. Petrushenko ◽

◽

...

Keyword(s):

Centrifugal Compressor ◽

Compressor Stage ◽

Guide Vanes ◽

Centrifugal Compressor Stage ◽

Inlet Guide Vanes

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Effects of Inlet Guide Vanes on the Performance and Stability of an Aeronautical Centrifugal Compressor

Volume 2E: Turbomachinery ◽

10.1115/gt2020-14149 ◽

2020 ◽

Author(s):

Nicolas Poujol ◽

Isabelle Trébinjac ◽

Pierre Duquesne

Keyword(s):

Mass Flow ◽

Flow Rate ◽

Centrifugal Compressor ◽

Compressor Stage ◽

Lower Mass ◽

Flow Angle ◽

Guide Vanes ◽

Inlet Guide Vanes ◽

Surge Line ◽

Stagger Angle

Abstract A research centrifugal compressor stage designed and built by Safran Helicopter Engines is tested at 3 IGV (Inlet Guide Vanes) stagger angles. The compressor stage includes 4 blade rows: axial inlet guide vanes, a backswept splittered impeller, a splittered vaned radial diffuser and axial outlet guide vanes. The methodology for calculating the performance is detailed, including the consideration of humidity in order to minimize errors related in particular to operating atmospheric conditions. The shift of the surge line towards lower mass flow rate as the IGV stagger angle increases highly depends on the rotation speed. The surge line shift is very small at low rotation speeds whereas it significantly increases at high rotation speeds. A firstorder stability analysis of the impeller and diffuser subcomponents shows that the diffuser (resp. impeller) is the first unstable component at low (resp. high) rotation speeds. This situation is unaltered by increasing the IGV stagger angle. At low rotation speeds below a given mass flow rate, rotating instabilities at the impeller inlet are detected at zero IGV stagger angle. Their occurrence is conditioned by the relative flow angle at the tip of the leading edge of the impeller. As the IGV stagger angle increases, the mass flow decreases to maintain a given inlet flow angle. Therefore, the onset of the rotating instabilities is delayed towards lower mass flow rates. At high rotation speeds, the absolute flow angle at the diffuser inlet near surge decreases as the IGV stagger angle increases. As a result, the flow is highly alternate over two adjacent channels of the radial diffuser beyond the surge line at IGV stagger angle of 0°.

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