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.

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.

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.

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.

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.

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.

Suppression of Secondary Flows in a Turbine Nozzle With Controlled Stacking Shape and Exit Circulation by 3D Inverse Design Method

1999 ◽  
Author(s):  
H. Watanabe ◽  
H. Harada
Keyword(s):  
Nozzle Exit ◽  
Inverse Method ◽  
Design Method ◽  
Secondary Flows ◽  
Inverse Design ◽  
Turbine Stage ◽  
Axial Turbine ◽  
Work Distribution ◽  
Inverse Design Method ◽  
3D Stacking

For the axial turbine stage, the design of circulation rVθ¯ distribution between the nozzle and blade has an important effect on the stage performance, because it determines the work distribution in the blade, the stage reaction and the twisting shape of the blade. This paper describes the new method of full 3D design for axial turbine nozzles and blades by applying the 3D inverse design method in which the blade geometry can be determined by specified distributions of circulation rVθ¯ and blade thickness. In this 3D inverse design method, spanwise work distribution of the turbine stage is controlled by specifying the rVθ¯ distribution of the nozzle exit. In this design procedure, rVθ¯ distribution at the nozzle exit and 3D stacking condition are both controlled by 3D inverse method so as to suppress the nozzle secondary flows effectively. The desirable rVθ¯ distribution and 3D stacking shape which were obtained by the 3D inverse method were confirmed by Dawes’ 3D Navier-Stokes analysis. The results shows that the secondary loss is reduced when the design rVθ¯ at the mid-span is set larger compared to that near the endwall. In addition to the control of the rVθ¯ distribution, 3D stacking shape added only in the front part of the nozzle is very effective to suppress the secondary flows, although this 3D stacking shape is very simple compared to a conventional bowed type stacking. Moreover, when this stacking shape is used, spanwise distribution of work does not change from the design condition unlike the case of conventional bowed type stacking shape. The results of single stage performance test conducted using an air turbine facility show an improvement in efficiency compared to the 2D designed stage and prove viability of the 30 inverse design of axial turbine blades.

Reformulation of a Three-Dimensional Inverse Design Method for Application in a High-Fidelity CFD Environment

2012 ◽  
Author(s):  
Michel van Rooij ◽  
Adam Medd
Keyword(s):  
Inverse Method ◽  
Design Method ◽  
Three Dimensional ◽  
Inverse Design ◽  
Design Quality ◽  
Specific Flow ◽  
Flow Solver ◽  
The Difference ◽  
Inverse Design Method ◽  
Stage Matching

Three-dimensional inverse design has been shown to be a reliable and powerful tool for facilitating the refinement of blading design and improving stage matching, thereby providing increased aero-design quality and productivity in difficult design situations. However, inverse design has not been incorporated widely into design systems. Reasons for this may be that many inverse techniques are limited to two dimensional problems, or are highly integrated with a specific flow solver and therefore difficult to integrate with proprietary or commercial CFD methods. A reformulation of a three-dimensional inverse design method is presented here that overcomes these limitations. The new method is fully consistent with viscous flow modeling. Camber modification is performed using a blade velocity derived from the difference between prescribed and actual pressure loading. The new inverse method completely eliminates differences between analysis and inverse calculations. Moreover, the reformulation effectively decouples the inverse method from the flow solver. This makes it possible to supplement any CFD-code with the developed inverse design module, provided an interface can be created between the solver and the inverse module through which to pass information on flow and mesh. This makes inverse design available to most design offices.

AN INVERSE DESIGN METHOD FOR A WING IN FULL CRUISING CONFIGURATION OF A REGIONAL AIRCRAFT VIA RANS APPROACH

2020 ◽  
Vol 51 (1) ◽  
pp. 1-13
Author(s):  
Anatoliy Longinovich Bolsunovsky ◽  
Nikolay Petrovich Buzoverya ◽  
Nikita Aleksandrovich Pushchin
Keyword(s):  
Design Method ◽  
Inverse Design ◽  
Inverse Design Method
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