Automated Blade Optimization and 3D CFD Analysis for an Axial Multistage GT Compressor Redesign

2006 ◽  
Author(s):  
Lars Moberg ◽  
Gianfranco Guidati ◽  
Sasha Savic
Keyword(s):  
Flow Analysis ◽  
Optimization Methods ◽  
Design System ◽  
Cfd Analysis ◽  
Controlled Diffusion ◽  
Repetitive Tasks ◽  
Blade Optimization ◽  
Through Flow ◽  
Compressor Design ◽  
Linux Cluster

This paper focuses on (1) the basic compressor layout based on meridional through flow analysis and (2) the re-design of blades and vanes using sophisticated automated design optimization methods. All tools and processes are integrated into a consistent Compressor Design System, which runs on a powerful Linux cluster. This design system allows designing, analyzing and documenting blade design in mostly automated way. This frees the engineer from repetitive tasks and allows him to concentrate on a physical understanding and improvement of the compressor. The tools and methods are illustrated on the basis of an actual ALSTOM compressor. The main objectives of this upgrade are a modest increase in mass flow and an efficiency improvement. The latter is to be achieved through the replacement of NACA blades by modern Controlled Diffusion Airfoils (CDA). Results are presented including a CFD analysis of the front stages of the baseline and upgrade compressor.

scholarly journals Maximizing Multistage Turbine Efficiency by Optimizing Hub and Shroud Shapes and Inlet and Exit Conditions of Each Blade Row

1999 ◽  
Author(s):  
Milan V. Petrovic ◽  
George S. Dulikravich ◽  
Thomas J. Martin
Keyword(s):  
Search Algorithm ◽  
Flow Analysis ◽  
Axial Flow ◽  
Multidisciplinary Optimization ◽  
Design System ◽  
Optimized Design ◽  
Turbine Efficiency ◽  
Through Flow ◽  
Blade Row ◽  
Multistage Turbine

By matching a well established fast through-flow analysis code and an efficient optimization algorithm, a new design system has been developed which optimizes hub and shroud geometry and inlet and exit flow-field parameters for each blade row of a multistage axial flow turbine. The compressible steady state inviscid through-flow code with high fidelity loss and mixing models, based on stream function method and finite element solution procedure, is suitable for fast and accurate flow calculation and performance prediction of multistage axial flow turbines at design and significant off-design conditions. A general-purpose hybrid constrained optimization package has been developed that includes the following modules: genetic algorithm, simulated annealing, modified Nelder-Mead method, sequential quadratic programming, and Davidon-Fletcher-Powell gradient search algorithm. The optimizer performs automatic switching among the modules each time when the local minimum is detected thus offering a robust and versatile tool for constrained multidisciplinary optimization. An analysis of the loss correlations was made to find parameters that have influence on the turbine performance. By varying seventeen variables per each turbine stage it is possible to find an optimal radial distribution of flow parameters at the inlet and outlet of every blade row. Simultaneously, an optimized meridional flow path is found that is defined by the optimized shape of the hub and shroud. The design system has been demonstrated using an example of a single stage transonic axial gas turbine, although the method is directly applicable to multistage turbine optimization. The comparison of computed performance of initial and optimized design shows significant improvement in the turbine efficiency at design and off-design conditions. The entire design optimization process is feasible on a typical single-processor workstation.

Accelerated Industrial Blade Design Based on Multi-Objective Optimization Using Surrogate Model Methodology

2008 ◽  
Author(s):  
A. Keskin ◽  
M. Swoboda ◽  
P. M. Flassig ◽  
A. K. Dutta ◽  
D. Bestle
Keyword(s):  
Surrogate Model ◽  
Flow Analysis ◽  
Optimization Methods ◽  
Geometric Constraints ◽  
Blade Design ◽  
Optimization Strategy ◽  
Multi Objective Optimization ◽  
Dimensional Parameter ◽  
Multi Objective ◽  
Blade Optimization

The intention of this paper is to provide an advanced aerodynamic blade design approach for industrial purposes which are basically characterized by limited development time, human and computing resources. From the industrial point of view, the demand for process acceleration and design optimization cannot be sufficiently satisfied with traditional human-based design methods. Recent investigations on blade optimization have shown some potential in performance improvements, however, this is typically obtained by high computational efforts in particular when using multi-objective optimization methods. In order to combine the benefits of numerical optimization with the requirements of industrial needs for design acceleration, a new automated blade optimization strategy is required. The accelerated industrial blade design process in this paper is based on a three-dimensional parameterization approach using non-dimensional parameter distributions which always guarantee desired blade geometry smoothness. In order to approximate the design objectives and constraints, a response surface methodology is applied where the design parameter variation is obtained by the quasi-random SOBOL sequence. Based on that, a highly sophisticated multi-objective genetic algorithm is used with reasonable numbers for individuals and generations for solving the contradicting design goals of an aerodynamic blade design problem by considering multiple aerodynamic and geometric constraints. This approach offers a set of non-dominated solutions on the Pareto-front which are subsequently evaluated with the exact flow analysis. In case of objective function value discrepancies between model and exact evaluations, an update of the surrogate model is performed including these additional solutions until the approximation response is equivalent to the exact analysis within a predefined tolerance. This new methodology shows a significant overall design time reduction particularly a decrease of required function evaluations without loosing the benefit of multi-objective optimization in providing Pareto-optimal solutions. Based on a typical industrial compressor test case, an aerodynamic performance improvement and process acceleration by factor greater than 10 could be achieved.

Axial Flow Compressor Design Optimization: Part II — Through-Flow Analysis

1989 ◽  
Author(s):  
Aristide Massardo ◽  
Antonio Satta ◽  
Martino Marini
Keyword(s):  
Design Optimization ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Axial Flow ◽  
Axial Flow Compressor ◽  
Through Flow ◽  
Compressor Design ◽  
Type Calculation ◽  
A New Technique ◽  
Flow Compressor

A new technique is presented for the design optimization of an axial-flow compressor stage. The procedure allows for optimization of the complete radial distribution of the geometry since the variables, chosen to represent the three dimensional geometry of the stage, are coefficients of suitable polynomials. Evaluation of the objective function is obtained with a through-flow type calculation, which has acceptable speed and stability qualities. Some examples are given of the possibility to use the procedure both for redesign and, together with what was presented in Part I, for the complete design of axial-flow compressor stages.

Mathematical Model to Describe Double Circular Arc and Multiple Circular Arc Compressor Blading Profiles

2021 ◽  
Author(s):  
John Kidikian ◽  
Chelesty Badrieh ◽  
Marcelo Reggio
Keyword(s):  
Flow Analysis ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Circular Arc ◽  
Engineering Software ◽  
Through Flow ◽  
Compressor Design ◽  
Design Software ◽  
Cartesian Coordinate ◽  
The One

Abstract For the past seven decades, a compressor aerodynamicist has developed various methodologies to design, analyze, and simulate compressor stages. In compressor design, three major subsequent steps can be identified: the one-dimensional mean-line methodology, the two-dimensional through-flow analysis, and the three dimensional computational fluid dynamics. One of the interconnecting threads, between these various x-dimensional analysis, is the compressor blade profile shape. This shape, of known and controllable geometric parameters, is usually accompanied by, or related to, loss models and known flow physics, either defined by theory or through experimental test. In this paper, a novel mathematical approach is described to define axial compressor airfoil profile shapes. These shapes, developed in a Cartesian coordinate system, can be used to create Double Circular Arc, Multiple Circular Arc, and a hybrid combination of the two types. The proposed methodology, based on the mathematics of circles, can be easily applied using generalized software such as Python or MATLAB, or be embedded in specialized engineering design software. In doing so, researchers and engineers can create compressor airfoil shapes which are consistent and flexible with respect to geometric parameter manipulation. Full details of the formulas, with respect to the camber line definition and the calculation of the profile intrados and extrados, are presented. A URL link to an equivalent MATLAB code, and a specialized engineering software, has been provided for those researchers that wish to apply the formulations and review its use.

Aerodynamic and Structure Considerations in Centrifugal Compressor Design: Blade Lean Effects

2012 ◽  
Author(s):  
C. Xu ◽  
R. S. Amano
Keyword(s):  
Centrifugal Compressor ◽  
Structural Reliability ◽  
Three Dimensional ◽  
Design System ◽  
Compressor Wheel ◽  
Through Flow ◽  
Compressor Design ◽  
Recent Developments ◽  
Compressor Performance ◽  
Wide Operating

Optimization procedures are demanded by turbomachinery industries that enable to enhance compressor efficiency and wide operating ranges. Most of the design processes focuseither on aerodynamics or structure. However, the compressor design is an integration between aerodynamics and structure. This paper presents some recent developments of the aerodynamic and structural integral design system. The design process including the meanline design, through-flow optimization and three-dimensional viscous analysis was used in the centrifugal compressor design. The aerodynamic and structural design need to be optimized at the same time. Normally most of the favorable aerodynamic features do not correspond with the structural reliability of the compressor wheel. The optimization between aerodynamic performance and structural reliability is critical to provide the maximal potential of the compressor performance. The main purpose of the current study is to discuss the importance of the aerodynamic and structural optimizations through a centrifugal compressor wheel lean effects. The study demonstrated that the integral design of the aerodynamics and structure is very important.

An Experimental Examination of Cantilevered and Shrouded Stators in a Multistage Axial Compressor

1998 ◽  
Author(s):  
M. Swoboda ◽  
P. C. Ivey ◽  
U. Wenger ◽  
V. Gümmer
Keyword(s):  
Large Scale ◽  
Flow Analysis ◽  
Axial Compressor ◽  
Pressure Rise ◽  
Experimental Investigations ◽  
Flow Angle ◽  
Stall Margin ◽  
Controlled Diffusion ◽  
Radial Profiles ◽  
Through Flow

This paper presents experimental investigations on a large-scale low-speed compressor facility with four repeating stages equipped with CDA-profiles (Controlled Diffusion Airfoils). Two different builds were investigated. Both builds used identical rotors, but had stators configured either in cantilevered or in shrouded form. Traverse measurements of total pressure and flow angle at six axial locations (IGV, two rotor and three stator exit planes) were performed between 1% and 99% annulus height and across two blade pitches. Circumferentially mass-averaged radial profiles were used in a through-flow code for reconstruction analysis of the measurements. In addition to the traverse measurements surface static pressures on stage 3 rotor and stator were measured. The effect of the “free-end” configuration on an embedded stage of this multistage compressor is described and compared to the shrouded configuration. The objective of this study was to investigate the differences of these two configurations and especially the effects caused by the hub clearance vortex in the cantilevered case. The entire set of measurements and through-flow analysis was performed at two operating points of the compressor i.e. at peak efficiency and near stall condition. Thus also the effects of the hub clearance vortex which influences the stall margin of the compressor are described. The analysis of the results shows slightly higher pressure rise coefficients for shrouded stators, but slightly higher stall margin in the cantilevered case. This is due to a stabilizing effect of the hub clearance vortex (cleans up separation on hub) in the cantilevered configuration because its direction is opposite to the secondary flow in the passage.

Hybrid Analysis of Gas Annular Seals With Energy Equation

2013 ◽  
Author(s):  
Patrick J. Migliorini ◽  
Alexandrina Untaroiu ◽  
William C. Witt ◽  
Neal R. Morgan ◽  
Houston G. Wood
Keyword(s):  
Experimental Data ◽  
Hybrid Method ◽  
Energy Equation ◽  
Flow Analysis ◽  
Experimental Studies ◽  
Rotor System ◽  
Bulk Flow ◽  
Outlet Temperature ◽  
Cfd Analysis ◽  
Annular Seals

Annular seals are used in turbomachinery to reduce secondary flow between regions of high and low pressure. In a vibrating rotor system, the non-axisymmetric pressure field developed in the small clearance between the rotor and the seal generate reactionary forces that can affect the stability of the entire rotor system. Traditionally, two analyses have been used to study the fluid flow in seals, bulk-flow analysis and computational fluid dynamics (CFD). Bulk-flow methods are computational inexpensive, but solve simplified equations that rely on empirically derived coefficients and are moderately accurate. CFD analyses generally provide more accurate results than bulk-flow codes, but solution time can vary between days and weeks. For gas damper seals, these analyses have been developed with the assumption that the flow can be treated as isothermal. Some experimental studies show that the difference between the inlet and outlet temperature temperatures is less than 5% but initial CFD studies show that there can be a significant temperature change which can have an effect on the density field. Thus, a comprehensive analysis requires the solution of an energy equation. Recently, a new hybrid method that employs a CFD analysis for the base state, unperturbed flow and a bulk-flow analysis for the first order, perturbed flow has been developed. This method has shown to compare well with full CFD analysis and experimental data while being computationally efficient. In this study, the previously developed hybrid method is extended to include the effects of non-isothermal flow. The hybrid method with energy equation is then compared with the isothermal hybrid method and experimental data for several test cases of hole-pattern seals and the importance of the use of energy equation is studied.

Study of the Change of Performance of an Elastic Vertical Hydrofoil With Deformation

2014 ◽  
Author(s):  
Alexander Führing ◽  
Subha Kumpaty ◽  
Chris Stack
Keyword(s):  
Water Flow ◽  
Lift Coefficient ◽  
Flow Analysis ◽  
Turbulence Models ◽  
Flow Property ◽  
Performance Data ◽  
Cfd Analysis ◽  
Ansys Fluent ◽  
Drag Forces ◽  
Fluid Flow Analysis

In external and internal fluid flow analysis using numerical methods, most attention is paid to the properties of the flow assuming absolute rigidity of the solid bodies involved. However, this is often not the case for water flow or other fluids with high density. The pressure forces cause the geometry to deform which in turn changes the flow properties around it. Thus, a one-way and two-way Fluid-Structure Interaction (FSI) coupling is proposed and compared to a CFD analysis of a windsurfing fin in order to quantify the differences in performance data as well as the properties of the flow. This leads to information about the necessity of the use of FSI in comparison to regular CFD analysis and gives indication of the value of the enhanced results of the deformable analysis applied to water flow around an elastically deformable hydrofoil under different angles of attack. The performance data and flow property evaluation is done in ANSYS Fluent using the k-ω SST and k-ε model with a y+ of 1 and 35 respectively in order to be able to compare the behavior of both turbulence models. It is found that the overall lift coefficient in general is lower and that the flow is less turbulent because of softer transition due to the deformed geometry reducing drag forces. It is also found that the deformation of the tip of the hydrofoil leads to vertical lift forces. For the FSI analysis, one-way and two-way coupling were incorporated leading to the ability to compare results. It has been found that one-way coupling is sufficient as long as there is no stall present at any time.

A Strategy for Multi-Point Compressor Blading Using Multi-Objective Optimization

2012 ◽  
Author(s):  
Alireza Fathi ◽  
Abdollah Shadaram ◽  
Mohammad Alizadeh
Keyword(s):  
Incidence Angle ◽  
Optimization Algorithms ◽  
Optimization Techniques ◽  
Design System ◽  
Design Calculation ◽  
Blade Design ◽  
Objective Functions ◽  
Multi Objective ◽  
First Case ◽  
Through Flow

This paper introduces a framework to perform a multi-objective multipoint aerodynamic optimization for an axial compressor blade. This framework considers through-flow design requirements and mechanical and manufacturing constraints. Typically, components of a blade design system include geometry generation tools, optimization algorithms, flow solvers, and objective functions. In particular, optimization algorithms and objective functions are tuned to reduce blade design calculation cost and to match designed blade performance to the through flow design criteria and mechanical and manufacturing constrains. In the present study, geometry parameters of blade are classified to three categories. For each category, a distinct optimization loop is applied. In outer loop, Gradient-based optimization techniques are used to optimize parameters of the second category and a two-dimensional compressible viscous flow code is used to simulate the cascade fluid flow. Surface curvature optimization is carried out in inner loop, and its objective function is defined by integrating the normalized curvature and curvature slope. The genetic algorithm is used to optimize the parameters in the interior loop. To highlight the capabilities of the design method and to develop design know-how, an initial profile is optimized with three different design philosophies. The highest performance improvement in the first case is 15% reduction in loss at design incidence angle. In the second case, 16.5% increase in allowable incidence angle range, improves blade’s performance at off design conditions.

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