scholarly journals The Use of Circumferentially Nonuniform Stators to Attenuate LP Compressor Rotor-Stator-Strut Aerodynamic and Mechanical Interactions

1996 ◽  
Author(s):  
Markland G. Jones ◽  
Michael T. Barton ◽  
Walter F. O’Brien
Keyword(s):  
Pressure Distribution ◽  
Computer Model ◽  
Static Pressure ◽  
Low Cost ◽  
Axial Compressor ◽  
Angle Distribution ◽  
Frequency Content ◽  
Trailing Edge ◽  
Static Pressure Distribution ◽  
Compressor Rotor

A potential flow computer model that can handle blade row interaction problems has been used to analyze the circumferential static pressure distribution at the trailing edge plane of the last rotor in an axial compressor which is produced by a downstream stator/strut system. The computer model is based on the Douglas-Neumann formulation. The code was used to design a circumferentially nonuniform stagger angle distribution for the stator that reduced the static pressure disturbance on the rotor. The predicted circumferential static pressure distribution and its resulting frequency content at the rotor trailing edge station for the baseline (uniform circumferential stagger angles) stator and for the optimized stator are compared to static pressure data and derived frequency content from engine tests of each configuration. The results show good agreement between the model predictions and the test data. The results are further confirmed by measurements of rotor strain levels with the baseline stator and with the optimized stator, which show a proportional decrease in rotor strain for the optimized stator configuration. Since incorporation of this low-cost modification, there has been no evidence of vibratory induced rotor distress, thereby improving engine reliability and maintainability and enhancing customer satisfaction.

The Use of a Circumferentially Nonuniform Stator to Attenuate Harmful Aerodynamic and Mechanical Interactions in an Advanced Mixed Flow Splittered Rotor/Tandem Variable Stator LP Compressor

2005 ◽  
Author(s):  
M. T. Barton ◽  
D. P. Gentile
Keyword(s):  
Pressure Distribution ◽  
Computer Model ◽  
Static Pressure ◽  
Pressure Variation ◽  
Test Sequence ◽  
Optimized Design ◽  
Angle Distribution ◽  
Gas Generator ◽  
Mixed Flow ◽  
Static Pressure Distribution

A potential flow computer model that can handle blade row interaction problems has been used to analyze the circumferential static pressure distribution at the trailing edge plane of an advanced mixed flow splittered rotor low pressure compressor produced by a downstream tandem stator/strut system. The computer model is based on the Douglas-Neumann formulation and features a powerful automated optimization feature which can define a restagger pattern that will either minimize stator blade-to-blade loading differences or minimize the circumferential static pressure nonuniformity on a preselected axial plane. The latter approach was used presently to design a circumferentially nonuniform stagger angle distribution for the second row of the tandem stator that reduced the circumferential static pressure variation, and consequently its harmonic excitation, on the upstream rotor. Comparison between the predicted static pressure distribution for the baseline case (with uniform stagger angles) and the optimized design showed a dramatic reduction in the circumferential pressure variation. Fourier analyses of the pressure distributions confirmed a substantial decrease in the magnitude of the harmonic index thought to be responsible for the observed severe rotor vibration. The analytical results were confirmed by back-to-back engine tests of the baseline and restaggered tandem stators, where light probe measurements of splitter blade synchronous response showed a proportional decrease in rotor response for the optimized stator configuration. The restagger was implemented quickly and easily using simple modifications to the stator unison ring. With the high splitter blade deflections reduced to an acceptable level, the engine was able to safely accelerate through the former prohibited speed range and continue with the planned test sequence. The restaggered stator design and test effort, from initial problem statement through a successful demonstration test in the gas generator, was accomplished in less than 6 weeks.

Adjoint Optimization of Multistage Axial Compressor Blades with Static Pressure Constraint at Blade Row Interface

2016 ◽  
Vol 33 (2) ◽  
Author(s):  
Jia Yu ◽  
Lucheng Ji ◽  
Weiwei Li ◽  
Weilin Yi
Keyword(s):  
Pressure Distribution ◽  
Adjoint Method ◽  
Static Pressure ◽  
Pressure Ratio ◽  
Axial Compressor ◽  
Optimal Solution ◽  
Optimization Procedure ◽  
Compressor Blades ◽  
Static Pressure Distribution ◽  
Practical Engineering

AbstractAdjoint method is an important tool for design refinement of multistage compressors. However, the radial static pressure distribution deviates during the optimization procedure and deteriorates the overall performance, producing final designs that are not well suited for realistic engineering applications. In previous development work on multistage turbomachinery blade optimization using adjoint method and thin shear-layer N-S equations, the entropy production is selected as the objective function with given mass flow rate and total pressure ratio as imposed constraints. The radial static pressure distribution at the interfaces between rows is introduced as a new constraint in the present paper. The approach is applied to the redesign of a five-stage axial compressor, and the results obtained with and without the constraint on the radial static pressure distribution at the interfaces between rows are discussed in detail. The results show that the redesign without the radial static pressure distribution constraint (RSPDC) gives an optimal solution that shows deviations on radial static pressure distribution, especially at rotor exit tip region. On the other hand, the redesign with the RSPDC successfully keeps the radial static pressure distribution at the interfaces between rows and make sure that the optimization results are applicable in a practical engineering design.

Shape Optimization of Multi-Stage Axial Compressor Blades Using Adjoint Method With Static Pressure Constraint at Blade Row Interface

2015 ◽  
Author(s):  
Jia Yu ◽  
Lucheng Ji ◽  
Weiwei Li ◽  
Weilin Yi
Keyword(s):  
Pressure Distribution ◽  
Adjoint Method ◽  
Static Pressure ◽  
Pressure Ratio ◽  
Axial Compressor ◽  
Optimal Solution ◽  
Optimization Procedure ◽  
Compressor Blades ◽  
Static Pressure Distribution ◽  
Multi Stage

Adjoint method is an important tool for design refinement of multistage compressors. However, the radial static pressure distribution deviates during the optimization procedure and deteriorates the overall performance, producing final designs that are not well suited for realistic engineering applications. In previous development work on multistage turbomachinery blade optimization using adjoint method and thin shear-layer N-S equations, the entropy production is selected as the objective function with given mass flow rate and total pressure ratio as imposed constraints. The radial static pressure distribution at the interfaces between rows is introduced as a new constraint in the present paper. The approach is applied to the redesign of a five-stage axial compressor, and the results obtained with and without the constraint on the radial static pressure distribution at the interfaces between rows are discussed in detail. The results show that the redesign without radial static pressure distribution constraint (RSPDC) gives an optimal solution that shows deviations on radial static pressure distribution, especially at rotor exit tip region. On the other hand, the redesign with the RSPDC successfully keeps the radial static pressure distribution at the interfaces between rows and make sure that the optimization results are applicable in a practical engineering design.

A New Three-Dimensional Viscous Inverse Design Method for Axial Compressor Blade

2016 ◽  
Author(s):  
Zhaowei Liu ◽  
Hu Wu
Keyword(s):  
Pressure Distribution ◽  
Static Pressure ◽  
Design Method ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Design Procedure ◽  
Inverse Design ◽  
Blade Surface ◽  
Static Pressure Distribution ◽  
Inverse Design Method

A recently developed aerodynamic inverse design method for axial compressor is presented in this paper. The inverse design method is based on solving the three-dimensional Reynolds-averaged Navier-Stokes equations. Blade surface static pressure distribution is prescribed before the design procedure. A new inverse design boundary condition is established based on the conservation of Riemann invariant on the blade surface. Blade profile is constantly modified by a virtual wall velocity which is obtained from the difference between the current and prescribed static pressure. The dynamic mesh theory is used to update the computation mesh where the shape of the blade is changing during the design process. The design procedure finishes after the prescribed static pressure distribution on the blade surface is satisfied. The method is first validated by a blade recovery test. It is then used to redesign the NASA Rotor 67.

Flow Analysis on a Single-Stage Axial Compressor With a Splitter Rotor

2004 ◽  
Author(s):  
Haipeng Li ◽  
Zhengping Zou ◽  
Huoxing Liu
Keyword(s):  
Unsteady Flow ◽  
Pressure Distribution ◽  
Load Distribution ◽  
Rotor Blade ◽  
Static Pressure ◽  
Flow Analysis ◽  
Axial Compressor ◽  
Flow Fields ◽  
Single Stage ◽  
Static Pressure Distribution

Unsteady and time-averaged flow fields of a single-stage axial compressor with a splitter rotor working in design conditions are simulated and analyzed with 3-D unsteady CFD code. The results show that strong unsteady flow exists in the rotor passage. Splitter reconstructs the pressure distribution in the rotor passage, changes load distribution of the rotor, and controls the flow near the rotor-blade. Splitter affects the unsteady static pressure distribution and fluctuation on principle blade, splitter and stator.

Ingestion Into the Upstream Wheelspace of an Axial Turbine Stage

1994 ◽  
Vol 116 (2) ◽  
pp. 327-332 ◽  
Author(s):  
T. Green ◽  
A. B. Turner
Keyword(s):  
Pressure Distribution ◽  
Static Pressure ◽  
Three Dimensional ◽  
Computer Code ◽  
Rotor Blades ◽  
Rotor Speed ◽  
Turbine Stage ◽  
Flow Rates ◽  
Static Pressure Distribution ◽  
Axial Clearance

The upstream wheelspace of an axial air turbine stage complete with nozzle guide vanes (NGVs) and rotor blades (430 mm mean diameter) has been tested with the objective of examining the combined effect of NGVs and rotor blades on the level of mainstream ingestion for different seal flow rates. A simple axial clearance seal was used with the rotor spun up to 6650 rpm by drawing air through it from atmospheric pressure with a large centrifugal compressor. The effect of rotational speed was examined for several constant mainstream flow rates by controlling the rotor speed with an air brake. The circumferential variation in hub static pressure was measured at the trailing edge of the NGVs upstream of the seal gap and was found to affect ingestion significantly. The hub static pressure distribution on the rotor blade leading edges was rotor speed dependent and could not be measured in the experiments. The Denton three-dimensional C.F.D. computer code was used to predict the smoothed time-dependent pressure field for the rotor together with the pressure distribution downstream of the NGVs. The level and distribution of mainstream ingestion, and thus the seal effectiveness, was determined from nitrous oxide gas concentration measurements and related to static pressure measurements made throughout the wheelspace. With the axial clearance rim seal close to the rotor the presence of the blades had a complex effect. Rotor blades in connection with NGVs were found to reduce mainstream ingestion seal flow rates significantly, but a small level of ingestion existed even for very high levels of seal flow rate.

Study of Semi-Inverse Problem for the Design of Annular S-Shaped Compressor Transition Duct

2015 ◽  
Author(s):  
Peng Shan ◽  
Jingyuan Wang ◽  
Zhentao Lv
Keyword(s):  
Inverse Problem ◽  
Pressure Distribution ◽  
Static Pressure ◽  
Pressure Coefficient ◽  
Optimal Solution ◽  
Outer Wall ◽  
Wall Pressure ◽  
Design Parameters ◽  
Gradient Distribution ◽  
Static Pressure Distribution

A new aerodynamic design strategy of the S-shaped transition duct between two compressor components was studied. Based on the controlled wall pressure gradient distribution and the wall velocity distribution, a semi-inverse problem of the transition duct was proposed, the corresponding inverse and direct approach codes were developed. To verify the feasibility of this method, two axial-centrifugal compressor transition ducts were designed. The results show that the static pressure distribution on the inner wall and the duct geometry both can be controlled freely by adjusting the inverse design parameters. The designed inner wall pressure distribution can be realized through a numerical matching procedure of the outer wall geometry based on the direct problem. The new design method is practicable that, without searching the optimal solution of the static pressure distribution of the inner wall, the total pressure coefficient can be at least 0.92.

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