Redesign of a Highly Loaded Transonic Turbine Nozzle Blade Using a New Viscous Inverse Design Method

2007 ◽  
Author(s):  
Kasra Daneshkhah ◽  
Wahid Ghaly
Keyword(s):  
Inverse Method ◽  
Design Method ◽  
Guide Vane ◽  
Accurate Solution ◽  
Inverse Design ◽  
Arbitrary Lagrangian Eulerian ◽  
Pressure Distributions ◽  
Transonic Turbine ◽  
Inverse Design Method ◽  
Highly Loaded

The redesign of VKI-LS89 turbine vane, which is typical of a highly loaded transonic turbine guide vane is presented. The redesign is accomplished using a new inverse design method where the blade walls move with a virtual velocity distribution derived from the difference between the current and the target pressure distributions on the blade surfaces. This new inverse method is fully consistent with the viscous flow assumption and is implemented into the time accurate solution of the Reynolds-Averaged Navier-Stokes (RANS) equations that are expressed in an arbitrary Lagrangian-Eulerian (ALE) form to account for mesh movement. A cell-vertex finite volume method is used to discretize the equations in space; time accurate integration is obtained using dual time stepping. An algebraic Baldwin-Lomax model is used for turbulence closure. The flow analysis formulation is first assessed against the LS89 experimental data. The inverse formulation that is implemented in the same code, is also assessed for its robustness and accuracy, by inverse designing the LS89 original geometry through running the inverse method with the original LS89 pressure distributions as target distributions but starting from an arbitrary geometry. The inverse design method is then used to redesign the LS89 using an arbitrary pressure distributions at a subsonic and a transonic outflow condition and the results are interpreted in terms of the blade overall aerodynamic performance.

Dual Point Redesign of Axial Turbines Using a Viscous Inverse Design Method

2009 ◽  
Author(s):  
Benedikt Roidl ◽  
Wahid Ghaly
Keyword(s):  
Inverse Method ◽  
Stokes Equations ◽  
Design Method ◽  
Single Point ◽  
Accurate Solution ◽  
Inverse Design ◽  
Suction Surface ◽  
Pressure Distributions ◽  
Wide Range ◽  
Inverse Design Method

A new dual-point inverse blade design method was developed and applied to the redesign of a highly loaded transonic vane, the VKI-LS89, and the first 2.5 stages of a low speed subsonic turbine, the E/TU-4 4-stage turbine that is built and tested at the university of Hannover, Germany. In this inverse method, the blade walls move with a virtual velocity distribution derived from the difference between the current and the target pressure distributions on the blade surfaces at both operating points. This new inverse method is fully consistent with the viscous flow assumption and is implemented into the time accurate solution of the Reynolds-Averaged Navier-Stokes equations. An algebraic Baldwin-Lomax turbulence model is used for turbulence closure. The mixing plane approach is used to couple the stator and rotor regions. The dual-point inverse design method is then used to explore the effect of different choices of the pressure distributions on the suction surface of one or more rotor/stator on the blade/stage performance. The results show that single point inverse design resulted in a local performance improvement whereas the dual point design method allowed for improving the performance of both VKI-LS89 vane and E/TU-4 2.5 stage turbines over a wide range of operation.

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.

Design of the Blade Geometry of Swept Transonic Fans by 3D Inverse Design

2003 ◽  
Author(s):  
H. Watanabe ◽  
M. Zangeneh
Keyword(s):  
Inverse Method ◽  
Design Method ◽  
Pressure Ratio ◽  
Inverse Design ◽  
Specific Work ◽  
Design Practice ◽  
Blade Loading ◽  
Inverse Design Method ◽  
Transonic Fan ◽  
Blade Geometry

The application of sweep in the design of transonic fans has been shown to be an effective method of controlling the strength and position of the shock wave at the tip of transonic fan rotors, and the control of corner separations in stators. In rotors sweep can extend the range significantly. However, using sweep in conventional design practice can also result in a change in specific work and therefore pressure ratio. As a result, laborious iterations are required in order to recover the correct specific work and pressure ratio. In this paper, the blade geometry of a transonic fan is designed with sweep using a 3D inverse design method in which the blade geometry is computed for a specified distribution of blade loading. By comparing the resulting flow field in the conventionally and inversely designed swept rotors, it is shown that it is possible to apply sweep without the need to iterate to maintain pressure ratio and specific work when using the inverse method.

A Compressible Three-Dimensional Inverse Design Method Based on the Streamline Curvature Approach and Clebsch Formulation for Radial and Mixed Flow Turbomachines

2012 ◽  
Author(s):  
Xiao Pei Tian ◽  
Peng Shan
Keyword(s):  
Flow Field ◽  
Inverse Method ◽  
Design Method ◽  
Inverse Design ◽  
Periodic Flow ◽  
Mixed Flow ◽  
3 Dimensional ◽  
Streamline Curvature ◽  
Through Flow ◽  
Inverse Design Method

The through-flow inverse design method based on the streamline curvature approach is nowadays a widely used quasi-3-dimensional blades design method for radial and mixed flow turbomachines. The main limitation of this method is using the flow field on the mean stream surface S2,m to approximate the actual 3-dimensional flow field. Without an effective description of the periodic flow, it is impossible for this method to realize exactly the prescribed circumferentially averaged swirl rVθ. Is there any way to develop this classical through-flow inverse method to a 3-dimensional one conveniently? The answer is yes. A new compressible 3-dimensional inverse design method for radial and mixed flow turbomachines is presented in this paper. This new 3-dimensional inverse method provides a convenient and effective way to obtain the periodic flow field for the streamline curvature through-flow inverse method. Meanwhile, compared with another type of similar 3-dimensional inverse method firstly described by Tan etc. based on Stokes stream functions and Monge potential functions from the Clebsch formulation to calculate the circumferentially averaged flow and the periodic flow respectively, this new method has its own advantages. In order to assess the usefulness of the new method, four centrifugal impellers are designed under the same design specifications by four different inverse methods respectively. They are two quasi-3-dimensional streamline curvature through-flow inverse methods without and with a slip factor model, a 3-dimensional approximated inverse approach based on stream functions and Monge potential functions and the 3-dimensional inverse method presented here. The performances of the four impellers yielding from a RANS commercial solver are compared. The capabilities of the four methods to realize the target circumferentially averaged swirl are also studied.

Redesign of a Low Speed Turbine Stage Using a New Viscous Inverse Design Method

2010 ◽  
Vol 133 (1) ◽  
Author(s):  
Benedikt Roidl ◽  
Wahid Ghaly
Keyword(s):  
Stokes Equations ◽  
Design Method ◽  
Accurate Solution ◽  
Inverse Design ◽  
Pressure Loading ◽  
Turbine Stage ◽  
Low Speed ◽  
Target Pressure ◽  
Stage Performance ◽  
Inverse Design Method

The midspan section of a low speed subsonic turbine stage that is built and tested at DFVLR, Cologne, is redesigned using a new inverse blade design method, where the blade walls move with a virtual velocity distribution derived from the difference between the current and target pressure distributions on the blade surfaces. This new inverse method is fully consistent with the viscous flow assumption and is implemented into the time-accurate solution of the Reynolds-averaged Navier–Stokes equations. An algebraic Baldwin–Lomax turbulence model is used for turbulence closure. The mixing plane approach is used to couple the stator and rotor regions. The computational fluid dynamics (CFD) analysis formulation is first assessed against the turbine stage experimental data. The inverse formulation that is implemented in the same CFD code is assessed for its robustness and merits. The inverse design method is then used to study the effect of the rotor pressure loading on the blade shape and stage performance. It is also used to simultaneously redesign both stator and rotor blades for improved stage performance. The results show that by carefully tailoring the target pressure loading on both blade rows, improvement can be achieved in the stage performance.

AN INVERSE DESIGN METHOD FOR METAMATERIAL SHRINKING DEVICE

2013 ◽  
Vol 27 (25) ◽  
pp. 1350182 ◽  
Author(s):  
TINGHUA LI ◽  
MING HUANG ◽  
JINGJING YANG ◽  
JIA ZENG ◽  
JIN LU
Keyword(s):  
Inverse Method ◽  
Effective Medium Theory ◽  
Design Method ◽  
Transformation Function ◽  
Inverse Design ◽  
Medium Theory ◽  
Material Parameters ◽  
Full Wave ◽  
Traditional Design ◽  
Inverse Design Method

In this paper, an inverse method to determine the parameters of metamaterial shrinking device is developed. Different from the traditional design method, of which the transformation function must be known in advance, this method allows us to directly obtain material parameters of device without any knowledge of the corresponding transformation function. Moreover, to further remove the inhomogeneity and anisotropy of material parameters, layered device composed of only homogeneous and isotropic materials is presented based on effective medium theory. The validity of such a method and shrinking effect of designed device are confirmed by full-wave simulations.

Redesign of a Low Speed Turbine Stage Using a New Viscous Inverse Design Method

2008 ◽  
Author(s):  
Benedikt Roidl ◽  
Wahid Ghaly
Keyword(s):  
Stokes Equations ◽  
Design Method ◽  
Accurate Solution ◽  
Inverse Design ◽  
Pressure Loading ◽  
Turbine Stage ◽  
Low Speed ◽  
Target Pressure ◽  
Stage Performance ◽  
Inverse Design Method

The midspan section of a low speed subsonic turbine stage that is built and tested at DFVLR, Cologne, is redesigned using a new inverse blade design method where the blade walls move with a virtual velocity distribution derived from the difference between the current and the target pressure distributions on the blade surfaces. This new inverse method is fully consistent with the viscous flow assumption and is implemented into the time accurate solution of the Reynolds-Averaged Navier-Stokes equations. An algebraic Baldwin-Lomax turbulence model is used for turbulence closure. The mixing plane approach is used to couple the stator and the rotor regions. The CFD analysis formulation is first assessed against the turbine stage experimental data. The inverse formulation that is implemented in the same CFD code is also assessed for its robustness and merits. The inverse design method is then used to study the effect of the rotor pressure loading on the blade shape and stage performance. It is also used to simultaneously redesign both stator and rotor blades for improved stage performance. The results show that by carefully tailoring the target pressure loading on both blade rows, improvement can be achieved in the stage performance.

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.

On the role of three-dimensional inverse design methods in turbomachinery shape optimization

1999 ◽  
Vol 213 (1) ◽  
pp. 27-42 ◽  
Author(s):  
M Zangeneh ◽  
A Goto ◽  
H Harada
Keyword(s):  
Flow Field ◽  
Inverse Method ◽  
Design Method ◽  
Three Dimensional ◽  
Design Guidelines ◽  
Secondary Flows ◽  
Inverse Design ◽  
Vaned Diffuser ◽  
Oil Flow ◽  
Inverse Design Method

The application of a three-dimensional (3D) inverse design method in which the blade geometry is computed for a specified distribution of circulation to the design of turbomachinery blades is explored by using two examples. In the first instance the method is applied to the design of radial and mixed flow impellers to suppress secondary flows. Based on our understanding of the fluid dynamics of the flow in the impeller, simple guidelines are developed for input specification of the inverse method in order to systematically design impellers with suppressed secondary flows and a more uniform exit flow field. In the second example the method is applied to the design of a vaned diffuser. Again based on the understanding of the detailed flow field in the diffuser obtained by using 3D viscous calculations and oil flow visualizations, simple design guidelines are developed for input specification to the inverse method in order to suppress corner separation. In both cases the guidelines are verified numerically and in the case of the diffuser further experimental validation is presented.

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