Toward Intra-Row Gap Optimization for One and Half Stage Transonic Compressor

2005 ◽  
Vol 127 (3) ◽  
pp. 589-598 ◽  
Author(s):  
H. D. Li ◽  
L. He
Keyword(s):  
Computing Time ◽  
Three Dimensional ◽  
Correction Method ◽  
Aerodynamic Performance ◽  
Current Approach ◽  
Influence Coefficient ◽  
Transonic Compressor ◽  
Shape Correction ◽  
Gap Spacing ◽  
Gap Effects

Multistage effects on both aerodynamics and aeromechanics have been identified as significant. Thus, design optimizations for both aerodynamic performance and aeromechanical stability should be done in the unsteady multistage environment. The key issue preventing such a procedure to be carried out is the enormous computing time cost of multistage unsteady simulations. In this paper, a methodology based on the single-passage shape-correction method integrated with an interface disturbance truncation technique has been developed. The capability, efficiency, and accuracy of the developed methodology have been demonstrated for a one and a half stage quasi-three-dimensional transonic compressor with realistic blade counts. Furthermore, the interface disturbance truncation technique enables us to separate multirow interaction effects from the upstream and the downstream, which makes it possible to superimpose different rotor upstream gap effects and rotor downstream gap effects on the middle row rotor aerodynamic damping. In addition, a gap influence coefficient approach has been developed for investigation of all the possible gap spacing combinations of M upstream stator-rotor gaps and N downstream rotor-stator gaps. Then the number of cases that need to be computed has been reduced from M×N to M+N, which saved substantial computing time. The optimization analysis shows significant damping variation (∼300%) within the chosen intrarow gap design space. The intrarow gap spacing could have either stabilizing or destabilizing effects so that the stabilizing axial spacing could be utilized to increase flutter-free margin in aeromechanical designs. The current approach also can be used for setting aeromechanical constraints for aerodynamic performance optimizations.

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

2003 ◽  
Vol 127 (3) ◽  
pp. 573-579 ◽  
Author(s):  
H. D Li ◽  
L. He
Keyword(s):  
Computational Study ◽  
Three Dimensional ◽  
Forced Response ◽  
Navier Stokes ◽  
Aerodynamic Damping ◽  
Transonic Compressor ◽  
Single Passage ◽  
Finite Volume Discretization ◽  
Shape Correction ◽  
Gap Spacing

One of the outstanding issues in turbomachinery aeromechanic analysis is the intrarow interaction effects. The present work is aimed at a systematic examination of rotor-stator gap effects on blade aerodynamic damping by using a three-dimensional (3D) time-domain single-passage Navier-Stokes solver. The method is based on the upwind finite volume discretization and the single-passage shape-correction approach with enhanced accuracy and efficiency for unsteady transonic flows prediction. A significant speedup (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% rotor tip 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% depending on the intrarow gap spacing. Furthermore, this rotor aerodamping dependency on the intrarow gap seems also to be affected by the number of stator blades. The predicted nonmonotonic relationship between the rotor blade aerodynamic damping and the gap spacing suggests the existence of an optimum gap regarding rotor flutter stability and/or forced response stress levels.

Prediction of Flutter and Inlet Distortion Driven Response of a Transonic Fan Rotor Using Phase-Lagged Boundary Conditions

2001 ◽  
Author(s):  
H. D. Li ◽  
L. He
Keyword(s):  
Computing Time ◽  
Three Dimensional ◽  
Correction Method ◽  
Forced Response ◽  
Navier Stokes ◽  
Design Environment ◽  
Inlet Distortion ◽  
Single Passage ◽  
Shape Correction ◽  
Transonic Fan

Prediction of blade forced response and flutter is of great importance to turbomachinery designers. However, calculations of unsteady turbomachinery flows using conventional time-domain methods typically would lead to the use of multi-passage/whole-annulus domains due to the required direct periodic condition. This makes numerical computations extremely time-consuming and is one of the major difficulties for nonlinear unsteady calculations to be applied in a blading design environment. A single-passage approach to three-dimensional unsteady Navier-Stokes calculations using the Fourier-series based Shape-Correction method has been developed, and been applied to analyze inlet distortion driven response and flutter of a transonic fan rotor (NASA Rotor-67). The key feature is that the Shape-Correction method enables a single-passage solution to unsteady flows in blade rows under influences of multiple disturbances with arbitrary inter-blade phase angles. The results show that the single-passage solution can capture deterministic unsteadiness as well as time-averaged flows in good agreement with conventional multi-passage solutions, while the corresponding computing time can be reduced dramatically.

Aerodynamic Design Optimization of an Axial Flow Compressor Rotor

2002 ◽  
Author(s):  
Chan-Sol Ahn ◽  
Kwang-Yong Kim
Keyword(s):  
Design Optimization ◽  
Response Surface ◽  
Computing Time ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Axial Flow ◽  
Navier Stokes ◽  
Transonic Compressor ◽  
Compressor Rotor ◽  
Design Variables

Design optimization of a transonic compressor rotor (NASA rotor 37) using the response surface method and three-dimensional Navier-Stokes analysis has been carried out in this work. The Baldwin-Lomax turbulence model was used in the flow analysis. Three design variables were selected to optimize the stacking line of the blade. Data points for response evaluations were selected by D-optimal design, and linear programming method was used for the optimization on the response surface. As a main result of the optimization, adiabatic efficiency was successfully improved. It was found that the optimization process provides reliable design of a turbomachinery blade with reasonable computing time.

A Double-Passage Shape Correction Method for Predictions of Unsteady Flow and Aeroelasticity in Turbomachinery

2017 ◽  
Vol 9 (4) ◽  
pp. 839-860 ◽  
Author(s):  
Tongqing Guo ◽  
Di Zhou ◽  
Zhiliang Lu
Keyword(s):  
Unsteady Flow ◽  
Turbulent Flows ◽  
Fourier Coefficients ◽  
Three Dimensional ◽  
Correction Method ◽  
Solution Stability ◽  
Shape Correction ◽  
Flow Variables ◽  
Transonic Fan ◽  
Solution Accuracy

AbstractIn this paper, a double-passage shape correction (DPSC) method is presented for simulation of unsteady flows around vibrating blades and aeroelastic prediction. Based on the idea of phase-lagged boundary conditions, the shape correction method was proposed aimed at efficiently dealing with unsteady flow problems in turbomachinery. However, the original single-passage shape correction (SPSC) may show the disadvantage of slow convergence of unsteady solutions and even produce nonphysical oscillation. The reason is found to be related with the disturbances on the circumferential boundaries that can not be damped by numerical schemes. To overcome these difficulties, the DPSC method is adopted here, in which the Fourier coefficients are computed from flow variables at implicit boundaries instead of circumferential boundaries in the SPSC method. This treatment actually reduces the interaction between the calculation of Fourier coefficients and the update of flow variables. Therefore a faster convergence speed could be achieved and also the solution stability is improved. The present method is developed to be suitable for viscous and turbulent flows. And for real three-dimensional (3D) problems, the rotating effects are also considered. For validation, a 2D oscillating turbine cascade, a 3D oscillating flat plate cascade and a 3D practical transonic fan rotor are investigated. Comparisons with experimental data or other solutions and relevant discussions are presented in detail. Numerical results show that the solution accuracy of DPSC method is favorable and at least comparable to the SPSC method. However, fewer iteration cycles are needed to get a converged and stable unsteady solution, which greatly improves the computational efficiency.

Experimental and Computational Study of Oscillating Turbine Cascade and Influence of Part-Span Shrouds

2009 ◽  
Vol 131 (5) ◽  
Author(s):  
X. Q. Huang ◽  
L. He ◽  
David L. Bell
Keyword(s):  
Experimental Data ◽  
Computational Study ◽  
Three Dimensional ◽  
Unsteady Flows ◽  
Correction Method ◽  
Influence Coefficient ◽  
Turbine Cascade ◽  
Test Configuration ◽  
Practical Applications ◽  
Influence Coefficient Method

This paper presents a combined experimental and computational study of unsteady flows in a linear turbine cascade oscillating in a three-dimensional bending/flapping mode. Detailed experimental data are obtained on a seven-bladed turbine cascade rig. The middle blade is driven to oscillate and oscillating cascade data are obtained using an influence coefficient method. The numerical simulations are performed by using a 3D nonlinear time-marching Navier–Stokes flow solver. Single-passage domain computations for arbitrary interblade phase angles are achieved by using the Fourier shape correction method. Both measurements and predictions demonstrate a fully 3D behavior of the unsteady flows. The influence of the aerodynamic blockage introduced by part-span shrouds on turbine flutter has been investigated by introducing flat plate shaped shrouds at 75% span. In contrast to practical applications, in the present test configuration, the mode of vibration of the blades remains unchanged by the introduction of the part-span shroud. This allows the influence of the aerodynamic blockage introduced by the part-span shroud to be assessed in isolation from the change in mode shape. A simple shroud model has been developed in the computational solver. The computed unsteady pressures around the shrouds are in good agreement with the experimental data, demonstrating the validity of the simple shroud model. Despite of notable variations in local unsteady pressures around the shrouds, the present results show that the blade aerodynamic damping is largely unaffected by the aerodynamic blockage introduced by part-span shrouds.

Aerodynamic design optimization of a compressor rotor with Navier—Stokes analysis

2003 ◽  
Vol 217 (2) ◽  
pp. 179-183 ◽  
Author(s):  
C-S Ahn ◽  
K-Y Kim
Keyword(s):  
Design Optimization ◽  
Response Surface ◽  
Computing Time ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Transonic Compressor ◽  
Compressor Rotor ◽  
Design Variables ◽  
Reliable Design

Design optimization of a transonic compressor rotor (NASA rotor 37) using the response surface method (RSM) and three-dimensional Navier-Stokes analysis has been carried out in this work. The Baldwin—Lomax turbulence model was used in the flow analysis. Three design variables were selected to optimize the stacking line of the blade. Data points for response evaluations were selected by D-optimal i design, and a linear programming method was used to optimize the response surface. As a main result of the optimization, adiabatic efficiency was successfully improved. It was found that the optimization process provides reliable design of a turbomachinery blade with reasonable computing time.

scholarly journals Numerical Simulations of Advanced Transonic Compressor Stages Using an Unsteady Quasi-Three-Dimensional Flow Solver

1995 ◽  
Author(s):  
Gerald J. Micklow ◽  
J. Paul Sauve ◽  
Karthikeyan Shivaraman
Keyword(s):  
Numerical Simulations ◽  
Numerical Scheme ◽  
Stokes Equations ◽  
Computing Time ◽  
Three Dimensional ◽  
Axial Flow ◽  
Numerical Results ◽  
Compressor Stage ◽  
Transonic Compressor ◽  
Exact Geometry

This study presents the results of numerical simulations of single stage transonic axial-flow compressors. The numerical scheme used solves the unsteady quasi-three-dimensional thin-layer Navier-Stokes equations. In the first part of the study, the validation of the numerical scheme for advanced transonic axial-flow compressor stages is presented. The results of a numerical simulation are compared to an experimentally tested transonic compressor stage of DFVLR. Further simulations are performed on an advanced transonic compressor stage design to investigate the effect of airfoil geometry re-scaling, in order to save computing time, on the numerical results. Two cases are simulated: a modified geometry where less stator blades are simulated and an exact geometry where the exact geometry is modeled. Good agreement is obtained between the experimental and numerical results for the first test case, indicating the validity of the quasi-three dimensional method. The last two simulations show that any significant re-scaling of the stage geometry will have an adverse effect on overall results. All of the simulations show that the unsteady rotor-stator interactions have a significant effect on stage performance.

Effects of stator splitter blades on aerodynamic performance of a single-stage transonic axial compressor

2020 ◽  
Vol 14 (4) ◽  
pp. 7369-7378
Author(s):  
Ky-Quang Pham ◽  
Xuan-Truong Le ◽  
Cong-Truong Dinh
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Aerodynamic Performance ◽  
Numerical Results ◽  
Single Stage ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Operating Stability ◽  
Length Coverage

Splitter blades located between stator blades in a single-stage axial compressor were proposed and investigated in this work to find their effects on aerodynamic performance and operating stability. Aerodynamic performance of the compressor was evaluated using three-dimensional Reynolds-averaged Navier-Stokes equations using the k-e turbulence model with a scalable wall function. The numerical results for the typical performance parameters without stator splitter blades were validated in comparison with experimental data. The numerical results of a parametric study using four geometric parameters (chord length, coverage angle, height and position) of the stator splitter blades showed that the operational stability of the single-stage axial compressor enhances remarkably using the stator splitter blades. The splitters were effective in suppressing flow separation in the stator domain of the compressor at near-stall condition which affects considerably the aerodynamic performance of the compressor.

A comparative study and combined application of RSM and ANN in adsorptive removal of diuron using biomass ashes

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Sunil K. Deokar ◽  
Nachiket A. Gokhale ◽  
Sachin A. Mandavgane
Keyword(s):  
Three Dimensional ◽  
Current Approach ◽  
Coefficient Of Determination ◽  
Ann Model ◽  
Operational Parameters ◽  
Initial Concentration ◽  
Combined Application ◽  
Artificial Neural Network Ann ◽  
Relationship Of ◽  
Biomass Ashes

Abstract Biomass ashes like rice husk ash (RHA), bagasse fly ash (BFA), were used for aqueous phase removal of a pesticide, diuron. Response surface methodology (RSM) and artificial neural network (ANN) were successfully applied to estimate and optimize the conditions for the maximum diuron adsorption using biomass ashes. The effect of operational parameters such as initial concentration (10–30 mg/L); contact time (0.93–16.07 h) and adsorbent dosage (20–308 mg) on adsorption were studied using central composite design (CCD) matrix. Same design was also employed to gain a training set for ANN. The maximum diuron removal of 88.95 and 99.78% was obtained at initial concentration of 15 mg/L, time of 12 h, RHA dosage of 250 mg and at initial concentration of 14 mg/L, time of 13 h, BFA dosage of 60 mg respectively. Estimation of coefficient of determination (R 2) and mean errors obtained for ANN and RSM (R 2 RHA = 0.976, R 2 BFA = 0.943) proved ANN (R 2 RHA = 0.997, R 2 BFA = 0.982) fits better. By employing RSM coupled with ANN model, the qualitative and quantitative activity relationship of experimental data was visualized in three dimensional spaces. The current approach will be instrumental in providing quick preliminary estimations in process and product development.

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