Improved Blade Profile Loss and Deviation Angle Models for Advanced Transonic Compressor Bladings: Part I—A Model for Subsonic Flow

1996 ◽  
Vol 118 (1) ◽  
pp. 73-80 ◽  
Author(s):  
W. M. Ko¨nig ◽  
D. K. Hennecke ◽  
L. Fottner
Keyword(s):  
Axial Flow ◽  
Deviation Angle ◽  
Simple Method ◽  
Subsonic Flows ◽  
New Model ◽  
Transonic Compressor ◽  
Blade Row ◽  
Inlet Conditions ◽  
Improved Accuracy ◽  
Profile Loss

New blading concepts as used in modern transonic axial-flow compressors require improved loss and deviation angle correlations. The new model presented in this paper incorporates several elements and treats blade-row flows having subsonic and supersonic inlet conditions separately. In the first part of this paper two proved and well-established profile loss correlations for subsonic flows are extended to quasi-two-dimensional conditions and to custom-tailored blade designs. Instead of a deviation angle correlation, a simple method based on singularities is utilized. The comparison between the new model and a recently published model demonstrates the improved accuracy in prediction of cascade performance achieved by the new model.

Improved Blade Profile Loss and Deviation Angle Models for Advanced Transonic Compressor Bladings: Part I — A Model for Subsonic Flow

1994 ◽  
Author(s):  
W. M. König ◽  
D. K. Hennecke ◽  
L. Fottner
Keyword(s):  
Axial Flow ◽  
Deviation Angle ◽  
Simple Method ◽  
Subsonic Flows ◽  
New Model ◽  
Transonic Compressor ◽  
Blade Row ◽  
Inlet Conditions ◽  
Improved Accuracy ◽  
Profile Loss

New blading concepts as used in modern transonic axial-flow compressors require improved loss and deviation angle correlations. The new model presented in this paper incorporates several elements and treats separately blade-row flows having subsonic and supersonic inlet conditions. In the first part of this paper two proved and well-established profile loss correlations for subsonic flows are extended to quasi twodimensional conditions and to custom-tailored blade designs. Instead of a deviation angle correlation a simple method based on singularities is utilized. The comparison between the new model and a recently published model demonstrates the improved accuracy in prediction of cascade performance achieved by the new model.

Improved Blade Profile Loss and Deviation Angle Models for Advanced Transonic Compressor Bladings: Part II—A Model for Supersonic Flow

1996 ◽  
Vol 118 (1) ◽  
pp. 81-87 ◽  
Author(s):  
W. M. Ko¨nig ◽  
D. K. Hennecke ◽  
L. Fottner
Keyword(s):  
Present Report ◽  
Axial Flow ◽  
Deviation Angle ◽  
New Model ◽  
Transonic Compressor ◽  
Supersonic Inlet ◽  
Blade Row ◽  
Flow Situation ◽  
Inlet Conditions ◽  
Profile Loss

New blading concepts as used in modern transonic axial-flow compressors require improved loss and deviation angle correlations. The new model presented in this paper incorporates several elements and treats blade-row flows having subsonic and supersonic inlet conditions separately. The second part of the present report focuses on the extension of a well-known correlation for cascade losses at supersonic inlet flows. It was originally established for DCA bladings and is now modified to reflect the flow situation in blade rows having low-cambered, arbitrarily designed blades including precompression blades. Finally, the steady loss increase from subsonic to supersonic inlet-flow velocities demonstrates the matched performance of the different correlations of the new model.

Improved Blade Profile Loss and Deviation Angle Models for Advanced Transonic Compressor Bladings: Part II — A Model for Supersonic Flow

1994 ◽  
Author(s):  
W. M. König ◽  
D. K. Hennecke ◽  
L. Fottner
Keyword(s):  
Present Report ◽  
Axial Flow ◽  
Deviation Angle ◽  
New Model ◽  
Transonic Compressor ◽  
Supersonic Inlet ◽  
Blade Row ◽  
Flow Situation ◽  
Inlet Conditions ◽  
Profile Loss

New blading concepts as used in modern transonic axial-flow compressors require improved loss and deviation angle correlations. The new model presented in this paper incorporates several elements and treats separately blade-row flows having subsonic and supersonic inlet conditions. The second part of the present report focuses on the extension of a well-known correlation for cascade losses at supersonic inlet-flows. It was originally established for DCA-bladings and is now modified to reflect the flow situation in blade-rows having low-cambered, arbitrarily designed blades including precompression blades. Finally, the steady loss increase from subsonic to supersonic inlet-flow velocities demonstrates the matched performance of the different correlations of the new model.

Stator-Rotor Interactions in a Transonic Compressor— Part 1: Effect of Blade-Row Spacing on Performance

2003 ◽  
Vol 125 (2) ◽  
pp. 328-335 ◽  
Author(s):  
Steven E. Gorrell ◽  
Theodore H. Okiishi ◽  
William W. Copenhaver
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Pressure Ratio ◽  
Axial Flow ◽  
Transonic Compressor ◽  
Blade Row ◽  
Spacing Variation ◽  
Stator Blade ◽  
Flow Compressor

Usually less axial spacing between the blade rows of an axial flow compressor is associated with improved efficiency. However, mass flow rate, pressure ratio, and efficiency all decreased as the axial spacing between the stator and rotor was reduced in a transonic compressor rig. Reductions as great as 3.3% in pressure ratio, and 1.3 points of efficiency were observed as axial spacing between the blade rows was decreased from far apart to close together. The number of blades in the stator blade-row also affected stage performance. Higher stator blade-row solidity led to larger changes in pressure ratio efficiency, and mass flow rate with axial spacing variation. Analysis of the experimental data suggests that the drop in performance is a result of increased loss production due to blade-row interactions. Losses in addition to mixing loss are present when the blade-rows are spaced closer together. The extra losses are associated with the upstream stator wakes and are most significant in the midspan region of the flow.

Influence of Sweep on Axial Flow Turbine Aerodynamics at Midspan

2006 ◽  
Vol 129 (3) ◽  
pp. 591-598 ◽  
Author(s):  
Graham Pullan ◽  
Neil W. Harvey
Keyword(s):  
Pressure Distribution ◽  
Axial Flow ◽  
Surface Velocity ◽  
Simple Method ◽  
Pressure Surface ◽  
Blade Area ◽  
Wetted Area ◽  
Loading Parameter ◽  
Turbine Design ◽  
Profile Loss

Sweep, when the stacking axis of the blade is not perpendicular to the axisymmetric streamsurface in the meridional view, is often an unavoidable feature of turbine design. Although a high aspect ratio swept blade can be designed to achieve the same pressure distribution as an unswept design, this paper shows that the swept blade will inevitably have a higher profile loss. A modified Zweifel loading parameter, taking sweep into account, is first derived. If this loading coefficient is held constant, it is shown that sweep reduces the required pitch-to-chord ratio and thus increases the wetted area of the blades. Assuming fully turbulent boundary layers and a constant dissipation coefficient, the effect of sweep on profile loss is then estimated. A combination of increased blade area and a raised pressure surface velocity means that the profile loss rises with increasing sweep. The theory is then validated using experimental results from two linear cascade tests of highly loaded blade profiles of the type found in low-pressure aeroengine turbines: one cascade is unswept, the other has 45deg of sweep. The swept cascade is designed to perform the same duty with the same loading coefficient and pressure distribution as the unswept case. The measurements show that the simple method used to estimate the change in profile loss due to sweep is sufficiently accurate to be a useful aid in turbine design.

Experimental Cascade Analysis of a Transonic Compressor Rotor Blade Section

1984 ◽  
Vol 106 (2) ◽  
pp. 288-294 ◽  
Author(s):  
H. A. Schreiber ◽  
H. Starken
Keyword(s):  
Rotor Blade ◽  
Flow Behavior ◽  
Density Ratio ◽  
Axial Flow ◽  
Flow Angle ◽  
Transonic Compressor ◽  
Compressor Rotor ◽  
Blade Row ◽  
Blade Section ◽  
Transonic Cascade

A transonic compressor rotor blade cascade was tested in order to elucidate the flow behavior in the transonic regime and to determine the performance characteristic in the whole operating range of a rotor blade section. The experiments have been conducted in a transonic cascade wind tunnel, which enables tests even at sonic inlet velocities. The influence of the upstream Mach number between 0.8 and 1.1 and the inlet flow angle between choking and stalling of the blade row was investigated. The effect of the axial velocity density ratio (AVDR) could be studied by applying an endwall suction device. Furthermore, the level of the shock losses was determined from a wake analysis. A final comparison of cascade losses and those of the corresponding rotor blade element shows good agreement which underlines the applicability of the cascade model in the design of axial flow turbomachines.

Stator-Rotor Interactions in a Transonic Compressor: Part 1 — Effect of Blade-Row Spacing on Performance

2002 ◽  
Author(s):  
Steven E. Gorrell ◽  
Theodore H. Okiishi ◽  
William W. Copenhaver
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Pressure Ratio ◽  
Axial Flow ◽  
Transonic Compressor ◽  
Blade Row ◽  
Spacing Variation ◽  
Stator Blade ◽  
Flow Compressor

Usually less axial spacing between the blade rows of an axial flow compressor is associated with improved efficiency. However, mass flow rate, pressure ratio, and efficiency all decreased as the axial spacing between the stator and rotor was reduced in a transonic compressor rig. Reductions as great as 3.3% in pressure ratio and 1.3 points of efficiency were observed as axial spacing between the blade-rows was decreased from far apart to close together. The number of blades in the stator blade-row also affected stage performance. Higher stator blade-row solidity led to larger changes in pressure ratio, efficiency, and mass flow rate with axial spacing variation. Analysis of the experimental data suggests that the drop in performance is a result of increased loss production due to blade-row interactions. Losses in addition to mixing loss are present when the blade-rows are spaced closer together. The extra losses are associated with the upstream stator wakes and are most significant in the mid-span region of the flow.

Experimental Evaluation of an Axial-Flow Transonic Compressor

1976 ◽  
Author(s):  
T. Tamaki ◽  
S. Nagano
Keyword(s):  
Rotational Speed ◽  
Velocity Ratio ◽  
Axial Flow ◽  
Rotating Stall ◽  
Test Results ◽  
Transonic Compressor ◽  
Multi Stage ◽  
Blade Row ◽  
Compressor Surge ◽  
Overall Performance

A five-stage transonic compressor was designed and tested to obtain overall performance and surge limits over a wide rotational speed range. Compressor surge limits are evaluated using individual stage performance characteristics with the aid of a single-stage test. These show that surging at low rotational speed occurs when rotating stall occurs in the first stage and that the wider operating range multi-stage compressor can be realized with the lower aspect ratio blades. On the basis of these test results, a simple model is constructed in order to evaluate the effect of the axial velocity ratio on the flow in a rotor blade row.

The Influence of Sweep on Axial Flow Turbine Aerodynamics at Mid-Span

2006 ◽  
Author(s):  
Graham Pullan ◽  
Neil W. Harvey
Keyword(s):  
Pressure Distribution ◽  
Axial Flow ◽  
Surface Velocity ◽  
Simple Method ◽  
Pressure Surface ◽  
Blade Area ◽  
Wetted Area ◽  
Loading Parameter ◽  
Turbine Design ◽  
Profile Loss

Sweep, when the stacking axis of the blade is not perpendicular to the axi-symmetric streamsurface in the meridional view, is often an unavoidable feature of turbine design. Although a high aspect ratio swept blade can be designed to achieve the same pressure distribution as an unswept design, this paper shows that the swept blade will inevitably have a higher profile loss. A modified Zweifel loading parameter, taking sweep into account, is first derived. If this loading coefficient is held constant, it is shown that sweep reduces the required pitch-to-chord ratio and so increases the wetted area of the blades. Assuming fully turbulent boundary layers, and a constant dissipation coefficient, the effect of sweep on profile loss is then estimated. A combination of increased blade area and a raised pressure surface velocity means that the profile loss rises with increasing sweep. The theory is then validated using experimental results from two linear cascade tests of highly loaded blade profiles of the type found in low pressure aeroengine turbines: one cascade is unswept, the other has 45 degrees of sweep. The swept cascade is designed to perform the same duty with the same loading coefficient and pressure distribution as the unswept case. The measurements show that the simple method used to estimate the change in profile loss due to sweep is sufficiently accurate to be a useful aid in turbine design.

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