scholarly journals Casing Treatments on a Supersonic Diffuser for High Pressure Ratio Centrifugal Compressors

1982 ◽  
Author(s):  
Y. Ribaud ◽  
P. Avram
Keyword(s):  
High Pressure ◽  
Mass Flow ◽  
Pressure Ratio ◽  
Centrifugal Compressors ◽  
Flow Variation ◽  
High Pressure Ratio ◽  
Supersonic Inlet ◽  
Diffuser Flow ◽  
Supersonic Diffuser ◽  
Casing Treatments

Centrifugal compressors with high pressure ratios from 7 to 10 often have a very slow mass flow margin. Suitable casing treatments, including large openings at the diffuser throat connected to annular plenums, greatly increase the reduced mass flow range of the diffuser during supersonic inlet operation. In the region of reduced mass flow variation, the reduction of the diffuser flow is associated with a drop of the effectiveness. The use of a backswept centrifugal rotor allows the experiment to overcome this penalty.

A Performance Autopsy of Three Centrifugal Compressors for a Small Gas Turbine

2010 ◽  
Author(s):  
Colin Rodgers ◽  
Dan Brown
Keyword(s):  
High Pressure ◽  
Gas Turbine ◽  
Radial Flow ◽  
Pressure Ratio ◽  
Test Results ◽  
Design Features ◽  
Centrifugal Compressors ◽  
High Pressure Ratio ◽  
Flow Type ◽  
The One

Three 140mm tip diameter centrifugal compressors were designed and tested to determine the one exhibiting the best performance most suitable for eventual application to a small 60KW radial flow type gas turbine. The design features, and stage test results of these three moderately high pressure ratio impellers are presented, together with a comparison of their respective test and CFD computed performance maps.

Impact of Main and Splitter Blade Leading Edge Contour on the Performance of High Pressure Ratio Centrifugal Compressors

2014 ◽  
Author(s):  
Rodrigo R. Erdmenger ◽  
Vittorio Michelassi
Keyword(s):  
High Pressure ◽  
Pressure Ratio ◽  
Leading Edge ◽  
Tip Clearance ◽  
Flow Coefficient ◽  
Centrifugal Compressors ◽  
Operating Range ◽  
High Pressure Ratio ◽  
The Impact ◽  
Blade Leading Edge

The impact of leading edge sweep in an attempt to reduce shock losses and extend the stall margin on axial compressors has been extensively studied, however only a few studies have looked at understanding the impact of leading edge contouring on the performance of centrifugal compressors. The present work studies the impact of forward and aft sweep on the main and splitter blade leading edge of a generic high flow coefficient and high pressure ratio centrifugal compressor design and the impact on its overall peak efficiency, pressure ratio and operating range. The usage of aft sweep on the main blade led to an increase of the pressure ratio and efficiency, however it also led to a reduction of the stable operating range of the impeller analyzed. The forward sweep cases analyzed where the tip leading edge was displaced axially forward showed a slight increase in pressure ratio, and a significant increase on operating range. The impact of leading edge sweep on the sensitivity of the impeller performance to tip clearance was also studied. The impeller efficiency was found to be less sensitive to an increase of tip clearance for both aft and forward sweep cases studied. The forward sweep cases studied also showed a reduced sensitivity from operating range to tip clearance. The studies conducted on the splitter leading edge profile indicate that aft sweep may help to increase the operating range of the impeller analyzed by up to 16% while maintaining similar pressure ratio and efficiency characteristics of the impeller. The improvement of operating range obtained with the leading edge forward sweep and splitter aft sweep was caused by a reduction of the interaction of the tip vortex of the main blade with the splitter tip, and a reduction of the blockage caused by this interaction.

scholarly journals Experimental Investigation of a High Pressure Ratio Aspirated Fan Stage

2004 ◽  
Author(s):  
Ali Merchant ◽  
Jack L. Kerrebrock ◽  
John J. Adamczyk ◽  
Edward Braunsheidel
Keyword(s):  
Experimental Investigation ◽  
High Pressure ◽  
Mass Flow ◽  
Pressure Ratio ◽  
Computational Prediction ◽  
Operating Conditions ◽  
High Pressure Ratio ◽  
Stage Performance ◽  
Design Speed ◽  
Computational Analyses

The experimental investigation of an aspirated fan stage designed to achieve a pressure ratio of 3.4:1 at 1500 feet/sec is presented in this paper. The low-energy viscous flow is aspirated from diffusion-limiting locations on the blades and flowpath surfaces of the stage, enabling a very high pressure ratio to be achieved in a single stage. The fan stage performance was mapped at various operating speeds from choke to stall in a compressor facility at fully simulated engine conditions. The experimentally determined stage performance, in terms of pressure ratio and corresponding inlet mass flow rate, was found to be in good agreement with the 3D viscous computational prediction, and in turn close to the design intent. Stage pressure ratios exceeding 3:1 were achieved at design speed, with an aspiration flow fraction of 3.5% of the stage inlet mass flow. The experimental performance of the stage at various operating conditions, including detailed flowfield measurements, are presented and discussed in the context of the computational analyses. The sensitivity of the stage performance and operability to reduced aspiration flow rates at design and off-design conditions are also discussed.

Experimental Aerodynamic Analysis Relative to Three High Pressure Ratio Centrifugal Compressors

1987 ◽  
Author(s):  
Y. Ribaud
Keyword(s):  
High Pressure ◽  
Pressure Ratio ◽  
Flow Coefficient ◽  
Careful Study ◽  
Test Results ◽  
Centrifugal Compressors ◽  
Inlet Flow ◽  
High Pressure Ratio ◽  
Experimental Parameters ◽  
Surge Line

The test results of three high pressure ratio centrifugal compressors are analyzed. Two of them show one or two discontinuities in the surge line. A careful study of the different experimental parameters indicates the existence of three different operating zones for the rotor. For the low inlet flow coefficients, two recirculations take place in the rotor: one at the inlet and the other at the outlet. For moderate flow coefficients, the outlet recirculation disappears. In these regions, the occurrence of these recirculations is explained and a simple model is given. The inlet recirculation can stabilize the flow if a 2D blade stall occurs but it is not possible in the third zone where the inlet flow coefficient is higher than the critical value.

The Effect of Inducer Shape on the Performance of High Pressure Ratio Centrifugal Compressors

1974 ◽  
Author(s):  
F. S. Bhinder ◽  
D. R. Ingham
Keyword(s):  
High Pressure ◽  
Radial Flow ◽  
Pressure Ratio ◽  
Performance Characteristics ◽  
Centrifugal Compressors ◽  
High Pressure Ratio ◽  
Meridional Profile ◽  
Inlet Angle

Three radial flow impellers, having different inducer blade shapes were designed, manufactured and tested. The inducer section of the impeller was changed in accordance with circular, parabolic and elliptical arc forms, but the meridional profile and the inducer blade inlet angle remained the same. The impellers were tested under nominally identical conditions covering top velocities up to 562 m/s (1844 ft/s). The performance characteristics are given and compared for all three impellers.

Design Considerations for High-Pressure-Ratio Centrifugal Compressors

1972 ◽  
Author(s):  
Colin Rodgers ◽  
Leon Sapiro
Keyword(s):  
High Pressure ◽  
Parametric Study ◽  
Low Cost ◽  
Pressure Ratio ◽  
Single Stage ◽  
Centrifugal Compressors ◽  
High Pressure Ratio ◽  
Design Considerations ◽  
Design Solutions ◽  
Improved Performance

Major design considerations involved in selecting geometries for high-pressure ratio, single-stage centrifugal compressors are discussed. The results of a parametric study are included to indicate optimum regions of design, and to project the potential performance of centrifugal compressors with rotating diffusers. Several different candidate design solutions are evaluated on the basis of providing improved performance at high pressure ratios consistent with maintaining the inherent simplicity and low-cost features of centrifugal compressors.

Influence of Tandem Inducers on the Performance of High Pressure Ratio Centrifugal Compressors

2015 ◽  
Author(s):  
Rodrigo R. Erdmenger ◽  
Vittorio Michelassi
Keyword(s):  
High Pressure ◽  
Pressure Ratio ◽  
Suction Side ◽  
Flow Coefficient ◽  
Centrifugal Compressors ◽  
Vaned Diffuser ◽  
High Pressure Ratio ◽  
Significant Performance ◽  
Inlet Conditions ◽  
The Impact

The uses of tandem inducers has been proposed in the past in an attempt to reduce the inducer shock losses and to improve the performance and operating range of centrifugal compressors. However throughout the literature the benefits/penalties of this type of compressor design are still unclear, with contradictory conclusions and very few studies attempting to understand the causes of the observed benefits/penalties. Additionally none of the cases reported for centrifugal compressors has looked into the impact of overlap between the inducer and the main blade. The current study looks into the different aspects of the design of centrifugal compressors with tandem inducers and their effect on the performance of a high flow coefficient, high pressure ratio centrifugal compressor. Aspects such as clocking, axial gap between the inducer and the compressor main blade, axial overlap, and the performance in combination with a vaned diffuser are discussed. Overall the results indicate that it is possible to design centrifugal compressors with tandem inducers that provide similar or even a slight performance benefit at design point, and that tandem inducers can provide significant performance benefits at off design conditions by improving the flow conditions along the main blade suction side, and by improving the inlet conditions to a vaned diffuser. The results also indicate that the impact of the axial gap between the inducer and the main blade has little impact on the compressor performance, that clocking will have a significant impact on the performance of the compressor and that the best performance will be obtained when the tandem inducer is almost aligned with the main blade of the compressor, since this avoids the blockage and losses incurred by other clocking arrangements.

scholarly journals Experimental Investigation of a High Pressure Ratio Aspirated Fan Stage

2005 ◽  
Vol 127 (1) ◽  
pp. 43-51 ◽  
Author(s):  
Ali Merchant ◽  
Jack L. Kerrebrock ◽  
John J. Adamczyk ◽  
Edward Braunscheidel
Keyword(s):  
Experimental Investigation ◽  
High Pressure ◽  
Mass Flow ◽  
Pressure Ratio ◽  
Computational Prediction ◽  
Operating Conditions ◽  
High Pressure Ratio ◽  
Stage Performance ◽  
Design Speed ◽  
Computational Analyses

The experimental investigation of an aspirated fan stage designed to achieve a pressure ratio of 3.4:1 at 1500 ft/s is presented in this paper. The low-energy viscous flow is aspirated from diffusion-limiting locations on the blades and flowpath surfaces of the stage, enabling a very high pressure ratio to be achieved in a single stage. The fan stage performance was mapped at various operating speeds from choke to stall in a compressor facility at fully simulated engine conditions. The experimentally determined stage performance, in terms of pressure ratio and corresponding inlet mass flow rate, was found to be in good agreement with the 3D viscous computational prediction, and in turn close to the design intent. Stage pressure ratios exceeding 3:1 were achieved at design speed, with an aspiration flow fraction of 3.5% of the stage inlet mass flow. The experimental performance of the stage at various operating conditions, including detailed flowfield measurements, are presented and discussed in the context of the computational analyses. The stage performance and operability at reduced aspiration flow rates at design and off-design conditions are also discussed.

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