Aerodynamic Optimization for the Transonic Compressor Stator Blade

2002 ◽  
pp. 163-172 ◽  
Author(s):  
Y. Yamaguchi ◽  
T. Arima
Keyword(s):  
Aerodynamic Optimization ◽  
Transonic Compressor ◽  
Stator Blade

scholarly journals Assessment of the Severity of Unsteady Mach Number Effects in a 3-Stage Transonic Compressor

2017 ◽  
Author(s):  
Anthony Dent ◽  
Liping Xu ◽  
Roger Wells
Keyword(s):  
Leading Edge ◽  
Compressor Stage ◽  
Pressure Potential ◽  
Cfd Simulations ◽  
Transonic Compressor ◽  
Inlet Guide Vanes ◽  
Great Consideration ◽  
Stator Blade ◽  
Front Stage ◽  
Stage Efficiency

In this paper results from steady and unsteady CFD simulations of an industrial transonic compressor are compared, in order to gain a better understanding of the cause of the differences in the predicted efficiencies between the steady and unsteady simulations. Initially the first stage is simulated as an isolated compressor stage with inlet guide vanes in order to analyse the effect of individual blade rows on the stage performance. It is found that the rotor efficiency is lower for steady simulations than for unsteady simulations due to stronger shock waves. The stator efficiency is greater in the steady simulations due to not being able to model the interaction of the rotor wakes with the stator blade leading edge and boundary layers. Greater variation between steady and unsteady predictions is found at higher operating speeds. In the 3-stage unsteady simulations, the front stage efficiency characteristic is the same as the efficiency calculated from the isolated unsteady simulations. This shows that the unsteady pressure potential propagating from the downstream stages has no significant effect on the front stage efficiency meaning that the designer does not need to give great consideration to the downstream blade rows when predicting the characteristics of the front stage.

Transonic Compressor Blade Optimization Integrated With Circumferential Groove Casing Treatment

2019 ◽  
Vol 141 (3) ◽  
Author(s):  
Weimin Song ◽  
Yufei Zhang ◽  
Haixin Chen ◽  
Kaiwen Deng
Keyword(s):  
Pressure Ratio ◽  
Compressor Blade ◽  
Superior Performance ◽  
Aerodynamic Optimization ◽  
Stall Margin ◽  
Casing Treatment ◽  
Integrated Optimization ◽  
Transonic Compressor ◽  
Circumferential Groove ◽  
Blade Optimization

A compressor blade integrated with circumferential groove casing treatment (CGCT) is optimized in this study. A hybrid aerodynamic optimization algorithm that combines the differential evolution (DE) with a radial basis function (RBF) response surface is used for the multi-objective optimization via the computational fluid dynamics (CFD) analysis. The sweep and lean distributions are optimized to pursue the maximum total pressure ratio and adiabatic efficiency at the design point. Constraints on the choking mass flow rate and the near-stall compression ratio are imposed to ensure the off-design performance. The performance is improved much more with the blade-CGCT integrated optimization than with the blade-only optimization. The stall margin of the blade-only optimized blade with CGCT added as an afterthought can be even worse than the baseline blade. The CGCT-removal test for the blade-CGCT integrated optimization result further verifies that the superior performance of the blade-CGCT integrated optimization is obtained via optimizing the coupling between the effects of the sweep and lean on the blade loading and the effects of the CGCT on the flow blockage.

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.

Stator-Rotor Interactions in a Transonic Compressor: Part 2 — Description of a Loss Producing Mechanism

2002 ◽  
Author(s):  
Steven E. Gorrell ◽  
Theodore H. Okiishi ◽  
William W. Copenhaver
Keyword(s):  
Pressure Wave ◽  
Pressure Ratio ◽  
Bow Shock ◽  
Trailing Edge ◽  
Transonic Compressor ◽  
Blade Row ◽  
Wave Forms ◽  
Stator Blade ◽  
Blade Row Interaction ◽  
Additional Loss

A previously unidentified loss producing mechanism resulting from the interaction of a transonic rotor blade-row with an upstream stator blade-row is described. This additional loss occurs only when the two blade rows are spaced closer together axially. Time-accurate simulations of the flow and high-response static pressure measurements acquired on the stator blade surface reveal important aspects of the fluid dynamics of the production of this additional loss. At close spacing the rotor bow shock is chopped by the stator trailing edge. The chopped bow shock becomes a pressure wave on the upper surface of the stator that is nearly normal to the flow and that propagates upstream. In the reference frame relative to this pressure wave, the flow is supersonic and thus a moving shock wave that produces an entropy rise and loss is experienced. The effect of this outcome of blade-row interaction is to lower the efficiency, pressure ratio, and mass flow rate observed as blade-row axial spacing is reduced from far to close. The magnitude of loss production is affected by the strength of the bow shock and how much it turns as it interacts with the trailing edge of the stator. At far spacing the rotor bow shock degenerates into a bow wave before it interacts with the stator trailing edge and no significant pressure wave forms on the stator upper surface. For this condition, no additional loss is produced.

scholarly journals Effects of Unsteady Flow Interactions on the Performance of a Highly-Loaded Transonic Compressor Stage

2015 ◽  
Author(s):  
Chunill Hah
Keyword(s):  
Total Pressure ◽  
Suction Side ◽  
Pressure Side ◽  
Rotor Wake ◽  
Transonic Compressor ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Compressor Design ◽  
Stator Blade ◽  
Total Temperature

The primary focus of this paper is to investigate the loss sources in an advanced GE transonic compressor design with high reaction and high stage loading. This advanced compressor has been investigated both experimentally and analytically in the past. The measured compressor efficiency is significantly lower than the efficiency calculated with various existing tools based on RANS and URANS. The general understanding is that some important flow physics in this modern compressor design are not represented in the current tools. To pinpoint the source of the efficiency miss, an advanced test with detailed flow traverse was performed for the front one and a half stage at the NASA Glenn Research Center. In the present paper, a Large Eddy Simulation (LES) is employed to determine whether a higher-fidelity simulation can pick up any additional flow physics that can explain past efficiency miss with RANS and URANS. The results from the Large Eddy Simulation were compared with the NASA test results and the GE interpretation of the test data. LES calculates lower total pressure and higher total temperature on the pressure side of the stator, resulting in large loss generation on the pressure side of the stator. On the other hand, existing tools based on the RANS and URANS do not calculate this high total temperature and low total pressure on the pressure side of the stator. The calculated loss through the stator from LES seems to match the measured data and the GE data interpretation. Detailed examination of the unsteady flow field from LES indicates that the accumulation of high loss near the pressure side of the stator is due to the interaction of the rotor wake with the stator blade. The strong rotor wake interacts quite differently with the pressure side of the stator than with the suction side of the stator blade. The concave curvature on the pressure side of the stator blade increases the mixing of the rotor wake with the pressure side boundary layer significantly. On the other hand, the convex curvature on the suction side of the stator blade decreases the mixing and the suction side blade boundary layer remains thin. The jet velocity in the rotor wake in the stator frame seems to magnify the curvature effect in addition to inviscid redistribution of wake fluid toward the pressure side of the blade.

Optimisation of a Stator Blade Used in a Transonic Compressor Cascade with Evolution Strategies

2000 ◽  
pp. 45-54 ◽  
Author(s):  
Markus Olhofer ◽  
Bernhard Sendhoff ◽  
Toshiyuki Arima ◽  
Toyotaka Sonoda
Keyword(s):  
Evolution Strategies ◽  
Compressor Cascade ◽  
Transonic Compressor ◽  
Stator Blade

A Model for Potential Deterministic Effects in Transonic Compressor Flows

2009 ◽  
Author(s):  
Stefan Stollenwerk ◽  
Dirk Nu¨rnberger
Keyword(s):  
Transport Model ◽  
Three Dimensional ◽  
Flat Plates ◽  
Additional Source ◽  
Shock Interactions ◽  
Transonic Compressor ◽  
Unsteady Interaction ◽  
Stator Blade ◽  
Unsteady Effects ◽  
The Impact

The unsteady interaction between blade rows is very important in highly loaded compressors because of its influence on operating performance. One important effect in this context is the impact of a rotor bow shock on the wake of an upstream stator blade. A new transport model is proposed which introduces such deterministic unsteady effects in a steady solution environment. Deterministic stresses are added to the stationary RANS equations by means of an additional source term. The presented approach combines the advantages of time-accurate and stationary simulation procedures, i.e. physical accuracy and computational efficiency. A generic cascade of flat plates and a transonic stator-rotor configuration are investigated numerically using time-accurate methods in order to analyze the wake-shock interactions. The results are compared with steady mixing-plane solutions to point out their shortcomings regarding unsteady effects and to illustrate the demands of a deterministic stress approach. The model is then calibrated for the generic cascade before it is applied to the real three-dimensional compressor stage.

Blade Aerodynamic Damping Variation With Rotor-Stator Gap: A Computational Study Using Single-Passage Approach

2003 ◽  
Author(s):  
H. D. Li ◽  
L. He
Keyword(s):  
Computational Study ◽  
Forced Response ◽  
Navier Stokes ◽  
Aerodynamic Damping ◽  
Transonic Compressor ◽  
Single Passage ◽  
Finite Volume Discretization ◽  
Shape Correction ◽  
Speed Up ◽  
Stator Blade

One of the outstanding issues in turbomachinery aeromechanic analysis is the intra-row interaction effects. The present work is aimed at a systematic examination of rotorstator gap effects on blade aerodynamic damping by using a 3D time-domain single-passage Navier-Stokes solver. The method is based on the upwind finite volume discretization (AUSMD/V) and the single-passage Shape-Correction approach with enhanced accuracy and efficiency for unsteady transonic flows prediction. A significant speed up (by a factor of 20) over to a conventional whole annulus solution has been achieved. A parametric study with different rotor-stator gaps (56%–216% chord) for a 3D transonic compressor stage illustrates that the reflection from an adjacent stator row can change rotor aerodynamic damping by up to 100%. It is shown that this intra-row interference effect on the rotor aero-damping can be qualitatively altered by changing the number of stator blades. Thus, the stator blade count could be considered as a useful aeromechanical control/design parameter. Furthermore, the predicted non-monotonic relationship between the rotor blade aerodynamic damping and the gap distance suggests the existence of an optimum gap regarding rotor flutter stability and/or forced response stress levels.

Unsteady Forcing vs. Efficiency: The Effect of Clocking on a Transonic Industrial Compressor

2013 ◽  
Author(s):  
Florian Fruth ◽  
Damian M. Vogt ◽  
Ronnie Bladh ◽  
Torsten H. Fransson
Keyword(s):  
Stokes Equations ◽  
Leading Edge ◽  
Forced Response ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Transonic Compressor ◽  
Design Changes ◽  
Transient Simulations ◽  
Stator Blade ◽  
The Impact

A numerical investigation on the impact of clocking on the efficiency and the aerodynamic forcing of the first 1.5 stages of an industrial transonic compressor was conducted. Using unsteady 3D Navier-Stokes equations, seven clocking positions were calculated and analyzed. Efficiency changes due to clocking were up to 0.125%, whereas modal excitation changes up to 31.7%. However, no direct correlation between the parameters of efficiency, stimulus and modal excitation was found as reported by others. It was found that potential forced response risks can be reduced by clocking, resulting only in minor efficiency penalties. Assuming almost sinusoidal behavior of efficiency and stimulus changes, as found in this investigation, both parameters can be set into correlation by using an ellipse interpolation. Direct impact of design changes on efficiency and stimulus through clocking can be deducted from that graph and quick estimations about extrema be made using only 5–6 transient simulations. Results however also stress the importance of considering modal excitation when optimizing for aerodynamic forcing, for which the ellipse interpolation is not necessarily possible. Highest efficiency is achieved with the IGV wake impinging on the stator blade leading edge at mid-span. It was found however that this alone is not a sufficient criteria in case of inclined wakes, as wake impingement at different span positions leads to different efficiencies.

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