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.

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.

scholarly journals Aerodynamic Inverse Design of Transonic Compressor Cascades with Stabilizing Elastic Surface Algorithm

2021 ◽  
Vol 11 (11) ◽  
pp. 4845
Author(s):  
Mohammad Hossein Noorsalehi ◽  
Mahdi Nili-Ahmadabadi ◽  
Seyed Hossein Nasrazadani ◽  
Kyung Chun Kim
Keyword(s):  
Design Method ◽  
Inverse Design ◽  
Normal Shock ◽  
Compressor Cascade ◽  
Elastic Surface ◽  
Transonic Compressor ◽  
Pressure Distributions ◽  
The Difference ◽  
Inverse Design Method ◽  
Transonic Cascade

The upgraded elastic surface algorithm (UESA) is a physical inverse design method that was recently developed for a compressor cascade with double-circular-arc blades. In this method, the blade walls are modeled as elastic Timoshenko beams that smoothly deform because of the difference between the target and current pressure distributions. Nevertheless, the UESA is completely unstable for a compressor cascade with an intense normal shock, which causes a divergence due to the high pressure difference near the shock and the displacement of shock during the geometry corrections. In this study, the UESA was stabilized for the inverse design of a compressor cascade with normal shock, with no geometrical filtration. In the new version of this method, a distribution for the elastic modulus along the Timoshenko beam was chosen to increase its stiffness near the normal shock and to control the high deformations and oscillations in this region. Furthermore, to prevent surface oscillations, nodes need to be constrained to move perpendicularly to the chord line. With these modifications, the instability and oscillation were removed through the shape modification process. Two design cases were examined to evaluate the method for a transonic cascade with normal shock. The method was also capable of finding a physical pressure distribution that was nearest to the target one.

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.

Rotational compressible inverse design method for two-dimensional, internal flow configurations

AIAA Journal ◽  
1993 ◽  
Vol 31 (3) ◽  
pp. 551-558 ◽  
Author(s):  
V. Dedoussis ◽  
P. Chaviaropoulos ◽  
K. D. Papailiou
Keyword(s):  
Design Method ◽  
Internal Flow ◽  
Inverse Design ◽  
Two Dimensional ◽  
Flow Configurations ◽  
Inverse Design Method

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.

scholarly journals Inverse Design of Centrifugal Compressor Vaned Diffusers in Inlet Shear Flows

1994 ◽  
Author(s):  
M. Zangeneh
Keyword(s):  
Flow Field ◽  
Centrifugal Compressor ◽  
Design Method ◽  
Internal Flow ◽  
Inviscid Flow ◽  
Inverse Design ◽  
Navier Stokes ◽  
Inlet Flow ◽  
Blade Thickness ◽  
The Difference

A 3D inverse design method in which the blade (or vane) geometry is designed for specified distributions of circulation and blade thickness is applied to the design of centrifugal compressor vaned diffusers. Two generic diffusers are designed, one with uniform inlet flow (equivalent to a conventional design) and the other with a sheared inlet flow. The inlet shear flow effects are modelled in the design method by using the so-called “Secondary Flow Approximation” in which the Bernoulli surfaces are convected by the tangentially mean inviscid flow field. The difference between the vane geometry of the uniform inlet flow and non-uniform inlet flow diffusers is found to be most significant from 50% chord to the trailing edge region. The flow through both diffusers are computed by using Denton’s 3D inviscid Euler solver and Dawes’ 3D Navier-Stokes solver under sheared inflow conditions. The predictions indicate improved pressure recovery and internal flow field for the diffuser designed for shear inlet flow conditions.

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.

A Robust Mixing Plane Method and its Application in 3D Inverse Design of Transonic Turbine Stages

2014 ◽  
Author(s):  
Saurya Ranjan Ray ◽  
Mehrdad Zangeneh
Keyword(s):  
Design Method ◽  
Flow Direction ◽  
Flow Analysis ◽  
Inverse Design ◽  
Plane Method ◽  
Design Variables ◽  
Wide Range ◽  
Inverse Design Method ◽  
Flow Variables ◽  
Flux Conservation

A robust mixing plane method satisfying interface flux conservation, non-reflectivity and retaining interface flow variation; valid at all Mach numbers and applicable for any machine configuration is formulated and implemented in a vertex based finite volume solver for flow analysis and inverse design of turbomachinery stage configurations. The formulation is based on superposing perturbed flow variables in the form of 3D characteristics obtained along the flow direction on the exchanged mixed out average quantities at the stage interface. A condition is derived in the mixed-out averaging procedure to distinguish between the subsonic and supersonic flow conditions at the interface. Using preconditioning technique, the new functionality is demonstrated to be applicable for a wide range of interface conditions and over different machine configurations with small spatial gap across the blade rows. The method is shown to satisfy flux conservation across the interface without generating spurious oscillations in the flow field at the domain boundaries and validated against available commercial solvers. Subsequently, a blade re-design approach in a multi-row configuration is conceptualised and demonstrated by the application of the 3D inverse design method on a single stage Low Pressure Turbine. Meridional load variation, stage reaction and blade stacking angle are considered as the design variables to explore the design space. Conducting design runs at a fixed mass flow boundary condition and similar overall loading condition; the optimised configuration is shown to satisfy redistributed meridional load, providing performance improvement while maintaining a similar level of flow rate and work extraction as the baseline configuration.

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.

Influence of Spanwise Distribution of Impeller Exit Circulation on Optimization Results of Mixed Flow Pump

2021 ◽  
Vol 11 (2) ◽  
pp. 507
Author(s):  
Mengcheng Wang ◽  
Yanjun Li ◽  
Jianping Yuan ◽  
Fareed Konadu Osman
Keyword(s):  
Design Method ◽  
Internal Flow ◽  
Inverse Design ◽  
Pump Efficiency ◽  
Mixed Flow ◽  
Baseline Model ◽  
Pump Impeller ◽  
First Case ◽  
Inverse Design Method ◽  
Flow Pump

The spanwise distribution of impeller exit circulation (SDIEC) has an important influence on the performance of the impeller. To quantitatively study the influence of SDIEC on optimization results, a comprehensive optimization system composed of the computational fluid dynamics, inverse design method, design of experiment, surrogate model, and optimization algorithm was used to optimize a mixed flow pump impeller in two different cases. In the first case, the influence of SDIEC was ignored, while in the second case, the influence of SDIEC was considered. The result shows that the optimization upper limit can be further improved when the influence of SDIEC is considered in the optimization process. The pump efficiency of the preferred optimized impeller F1 obtained in the first case at 1.2Qdes, 1.0Qdes, and 0.8Qdes are increased by 6.48%, 2.41%, and 0.06%, respectively, over the baseline model. Moreover, the pump efficiency of the preferred optimized impeller S2 obtained in the second case further increased by 0.76%, 1.24%, and 1.21%, respectively, over impeller F1. Furthermore, the influence of SDIEC on the performance of the mixed flow pump is clarified by a comparative analysis of the internal flow field.

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