Redesigning Annular Turbine Blade Rows Using a Viscous-Inviscid Inverse Design Method

2008 ◽  
Author(s):  
J. C. Pa´scoa ◽  
A. C. Mendes ◽  
L. M. C. Gato
Keyword(s):  
Turbine Blade ◽  
Design Method ◽  
Thickness Distribution ◽  
Tangential Velocity ◽  
Inverse Design ◽  
Angle Distribution ◽  
Flow Angle ◽  
Design Algorithm ◽  
Blade Thickness ◽  
Inverse Design Method

This paper presents the results of the aerodynamic redesign of an annular turbine blade row. The inverse method herein applied is an extension to 3D of an iterative inverse design method based on the imposition of the blade load, thickness distribution and stacking line. We define a mass-averaged mean tangential velocity over one blade pitch, ru¯θ, as the main design variable, since its derivative is related to the aerodynamic load. A time-lagged formulation for the 3D camber surface generator is given in order to include the blade thickness distribution into the design algorithm. The hybrid viscous-inviscid design code comprises three main components: the blade update algorithm; a fast inviscid 3D Euler code; and a viscous analysis code. The blade geometry and flow conditions are typical of LP turbine nozzle guide vanes. The design method will demonstrate its ability to redesign blade rows that achieve lower flow losses and a more uniform exit flow angle distribution. The performance of the new blades is checked by means of a Navier-Stokes computation using the κ–ε turbulence model. The presented results show a minor decrease in the losses and a better redistribution of the exit flow angle.

Optimization of Microturbine Aerodynamics Using CFD, Inverse Design and FEM Structural Analysis: 2nd Report — Turbine Design

2004 ◽  
Author(s):  
Hiroyoshi Watanabe ◽  
Hidenobu Okamoto ◽  
Shijie Guo ◽  
Akira Goto ◽  
Mehrdad Zangeneh
Keyword(s):  
Structural Reliability ◽  
Design Method ◽  
Thickness Distribution ◽  
Three Dimensional ◽  
Inverse Design ◽  
Blade Profile ◽  
Performance Improvements ◽  
Radial Turbine ◽  
Blade Thickness ◽  
Inverse Design Method

In this second report, a new aerodynamic design is presented for a radial turbine stage of a microturbine engine. To optimize three-dimensional (3-D) flows, an inverse design method, in which 3-D blade geometry is numerically obtained for specified blade loading distribution, has been applied together with numerical assessment using CFD (Computational Fluid Dynamics) and FEM (Finite Element Method). The runner blade profile along the hub surface was modified to attain nearly radially arranged blade elements especially at the exducer part of the radial turbine in order to achieve required structural strength. Also the blade thickness distribution was optimized to avoid vibration resonance and to meet creep strength requirements. The blade profile along the shroud surface was optimized via 3-D inverse design and CFD. CFD predicted aerodynamic performance of the modified turbine runner was confirmed to be similar to that of the fully 3-D blade shape, while maintaining structural reliability. The turbine nozzle also has been re-designed by using the inverse design method, with stage performance improvements confirmed by stage calculations using CFD.

Aerodynamic Design of S-Shaped Diffusers Using Ball–Spine Inverse Design Method

2014 ◽  
Vol 136 (12) ◽  
Author(s):  
A. Madadi ◽  
M. J. Kermani ◽  
M. Nili-Ahmadabadi
Keyword(s):  
Design Method ◽  
Three Dimensional ◽  
Inverse Design ◽  
3D Design ◽  
Cross Sectional ◽  
Design Algorithm ◽  
Flow Solver ◽  
Duct Geometry ◽  
Sst Turbulence Model ◽  
Inverse Design Method

Recently, an inverse design algorithm called ball–spine algorithm (BSA) was introduced for the design of 2D ducts. In this approach, the walls are considered as a set of virtual balls that can move freely along the straight directions called spines. In the present work, the method is developed for quasi-three-dimensional (quasi-3D) design of S-shaped ducts with a predefined width. To do so, the upper and lower lines of the S-duct symmetric section are modified under the BSA and then, the 3D S-duct geometry is obtained based on elliptic cross-sectional profiles. The target pressure distributions (TPDs) along the upper and lower lines are prescribed so that separation does not occur. Finally, the flow through the designed S-duct is numerically analyzed using a viscous flow solver with the SST turbulence model to validate the designed S-duct performance. The performance of the designed S-duct is compared to original and optimized versions of a benchmark S-duct diffuser. Results show that the present S-duct has a better performance.

On Design of Transonic Fan Rotors by 3D Inverse Design Method

2006 ◽  
Author(s):  
Peixin Hu ◽  
Mehrdad Zangeneh ◽  
Benjamin Choo ◽  
Mohammad Rahmati
Keyword(s):  
Structural Integrity ◽  
Design Method ◽  
Leading Edge ◽  
Tip Clearance ◽  
Inverse Design ◽  
Pressure Loading ◽  
Tip Clearance Flow ◽  
Blade Thickness ◽  
Inverse Design Method ◽  
Transonic Fan

The application of 3D inverse design to transonic fans can offer designers many advantages in terms of reduction in design time and providing a more direct means of using the insight obtained into flow physics from CFD computations directly in the design process. A number of papers on application of inverse design method to transonic fans have already been reported. However, in order to apply this approach in product design a number of issues need to be addressed. For example, how can the method be used to affect and control the fan rotor characteristics? The robustness of the method and its ability to deal with accurate representation of leading and trailing edges, as well as tip clearance flow. In this paper the further enhancement of the 3D viscous transonic inverse design code TURBOdesign-2 and its application to the re-design of NASA37 and NASA67 rotors will be described. In this inverse design method the blade geometry can be computed by the specification of the blade loading (meridional derivative of rVθ) or the pressure loading. In both cases the blade normal thickness is specified to ensure structural integrity of the design. Improvements to the code include implementation of full approximation storage (FAS) multigrid technique in the solver, which increases the speed of the computation. This method allows the modification of blade thickness and pressure loading by B-splines. In addition improvements have been made in the treatment of proper leading edge geometry. Two well known examples of NASA 67 and NASA 37 rotors are used to provide a step-by-step guide to the application of the method to the design of transonic fan rotors. Improved designs are validated by commercial CFD code CFX.

Performance Improvement of a Centrifugal Compressor Using a Developed 3D Inverse Design Method

2012 ◽  
Author(s):  
Mahdi Nili-Ahmadabadi ◽  
Farzad Poursadegh ◽  
Majid R. Shahhosseini
Keyword(s):  
Performance Improvement ◽  
Centrifugal Compressor ◽  
Stokes Equations ◽  
Design Method ◽  
Inverse Design ◽  
Meridional Plane ◽  
3D Analysis ◽  
3D Design ◽  
Design Algorithm ◽  
Inverse Design Method

This paper is concerned with performance improvement of a centrifugal compressor by evolution of an inverse design method for 3D design approaches. The design procedure encompasses two major steps. Firstly, using the BSA inverse design algorithm on the meridional plane of the impellers, the meridional geometries for impellers are defined based on modified pressure distribution. Furthermore, an original and progressive algorithm is developed for 3D design of angular coordinates of the impellers on the blade to blade planes of them based on blades loading improvements. Full 3D analysis of the designed compressor using Reynolds Average Navier-Stokes equations, and its comparison with the analysis results of the current compressor, shows that the total pressure ratio of the designed compressor at the same operation condition is enhanced more than 5 percent.

Aerodynamic Design of S-Shaped Diffusers Using Ball Spine Inverse Design Method

2014 ◽  
Author(s):  
Ali Madadi ◽  
Mahdi Nili-Ahmadabadi ◽  
Mohammad Jafar Kermani
Keyword(s):  
Design Method ◽  
Inverse Design ◽  
Cross Sectional ◽  
Design Algorithm ◽  
Flow Solver ◽  
Pressure Distributions ◽  
Duct Geometry ◽  
Sst Turbulence Model ◽  
Target Pressure ◽  
Inverse Design Method

Recently, an inverse design algorithm called ball-spine algorithm (BSA) is introduced for the design of 2-D ducts. In this approach, the walls are considered as a set of virtual balls that can freely move along the straight directions called spines. In the present work the method is developed for quasi 3-D design of S-shaped ducts with a predefined width. To do so, the upper and lower lines of the S-duct symmetric section are modified under the BSA and then, the 3-D S-duct geometry is obtained based on elliptic cross sectional profiles. The target pressure distributions along the upper and lower lines are prescribed so that the separation does not occur. Finally, the flow through the designed S-duct is numerically analyzed using a viscous flow solver with the SST turbulence model to validate the designed S-duct performance.

Redesign of a Transonic Compressor Rotor by Means of a Three-Dimensional Inverse Design Method: A Parametric Study

2007 ◽  
Author(s):  
Duccio Bonaiuti ◽  
Abeetha Pitigala ◽  
Mehrdad Zangeneh ◽  
Yansheng Li
Keyword(s):  
Design Method ◽  
Thickness Distribution ◽  
Three Dimensional ◽  
Tip Clearance ◽  
Inverse Design ◽  
Design Parameters ◽  
Geometrical Parameters ◽  
Blade Loading ◽  
Inverse Design Method ◽  
The Impact

In the present paper, the redesign of a transonic rotor was performed by means of a three-dimensional viscous inverse design method. The inverse approach used in this work is one where the pressure loading, blade thickness distribution and stacking axis are specified and the camber surface is calculated accordingly. The design of transonic and supersonic axial compressors strongly relies on the ability to control the shock strength, location and structure. The use of an inverse design method allows one to act directly on aerodynamic parameters, like the blade loading, and provides an efficient tool to control the shock wave and its interaction with the boundary and secondary flows and with the tip clearance vortex. In the present study, the parametric investigation of the blade loading distribution was carried out. Few design parameters, with immediate physical meaning, were required to control the three-dimensional blade loading, and their impact on the design and off-design performance of the rotor was assessed by means of CFD calculations. Further investigations were then performed in order to study the impact on the rotor performance of the geometrical parameters (meridional channel and thickness distribution), which must be imposed in the design with the inverse method. As a result, it was possible to develop guidelines for the aerodynamic design of transonic rotors that can be exploited for similar design applications.

Inviscid-Viscous Interaction Method for 3D Inverse Design of Centrifugal Impellers

1993 ◽  
Author(s):  
M. Zangeneh
Keyword(s):  
Design Method ◽  
Thickness Distribution ◽  
Pressure Ratio ◽  
Inverse Design ◽  
Navier Stokes ◽  
Viscous Effects ◽  
High Pressure Ratio ◽  
Circulation Distribution ◽  
Inverse Design Method ◽  
Blade Geometry

A 3D inverse design method for the design of the blade geometry of centrifugal compressor impellers is presented. In this method the blade shape is computed for a specified circulation distribution, normal (or tangential) thickness distribution and meridional geometry. As the blade shapes are computed by using an inviscid slip (or flow tangency) condition, the viscous effects are introduced indirectly by using a viscous/inviscid procedure. The 3D Navier-Stokes solver developed by Dawes is used as the viscous method. Two different approaches are described for incorporating the viscous effects into the inviscid design method. One method is based on the introduction of an aerodynamic blockage distribution throughout the meridional geometry. While in the other approach a vorticity term directly related to the entropy gradients in the machine is introduced. The method is applied to redesign the blade geometry of Eckardt’s 30° backswept impeller as well as a generic high pressure ratio (transonic) impeller. The results indicate that the entropy gradient approach can fairly accurately represent the viscous effects in the machine.

Airfoil Shape Design via Elastic Surface Inverse Design Method

2014 ◽  
Author(s):  
M. Nili-Ahmadabadi ◽  
M. Safari ◽  
A. Ghaei ◽  
E. Shirani
Keyword(s):  
Convergence Rate ◽  
Pressure Distribution ◽  
Design Method ◽  
Flow Analysis ◽  
Flow Regimes ◽  
Inviscid Flow ◽  
Inverse Design ◽  
Elastic Surface ◽  
Design Algorithm ◽  
Inverse Design Method

In this research, a novel inverse design algorithm called, Elastic Surface Algorithm (ESA), is developed for viscose and inviscid external flow regimes. ESA is a physically based iterative inverse design method that uses flow analysis code to estimate the pressure distribution on the solid structure, i.e. airfoil, and a 2D solid beam finite element code to calculate the deflections due to the difference between the calculated and target pressure distribution. The proposed method is validated through the inverse design of three different airfoils. In addition, two design examples are presented to prove the robustness of the method in various flow regimes. Also, the convergence rate of this method is compared with flexible membrane method (MGM) and Ball-Spine Algorithm (BSA) methods in inviscid flow regime. The results of this study showed that not only the ESA method is an effective method for inverse design of airfoils, but also it can considerably increase the convergence rate in transonic flow regimes.

A Novel 2D Incompressible Viscous Inverse Design Method for Internal Flows Using Flexible String Algorithm

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Mahdi Nili-Ahmadabadi ◽  
Ali Hajilouy-Benisi ◽  
Farhad Ghadak ◽  
Mohammad Durali
Keyword(s):  
Compressible Flows ◽  
Design Method ◽  
Flow Analysis ◽  
Internal Flow ◽  
Separated Flow ◽  
Inverse Design ◽  
Design Algorithm ◽  
String Algorithm ◽  
The Difference ◽  
Inverse Design Method

In this investigation, the flexible string algorithm (FSA), used before for inverse design of subsonic and supersonic ducts in compressible flows with and without normal shock, is developed and applied for inverse design of 2D incompressible viscous internal flow with and without separation. In the proposed method, the duct wall shape is changed under an algorithm based on deformation of a virtual flexible string in flow. At each modification step, the difference between current and target wall pressure distributions is applied to the string. The method is an iterative inverse design method and utilizes the analysis code for the flow field solution as a black-box. Some validation test cases and design examples are presented here, which show the robustness and flexibility of the method in handling complex geometries. In cases with separated flow pressure distribution, a unique solution for inverse design problem does not exist. The design algorithm is a physical and quick converging approach and can efficiently utilize commercial flow analysis software.

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