Aerodynamic Inverse Design of Turbomachinery Blading in Two-dimensional Viscous Flow PDF Download
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Author: Kasra Daneshkhah
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
An inverse blade design method, applicable to 2D and 3D flow in turbomachinery blading is developed and is implemented for the design of 2D cascades in compressible viscous flow. The prescribed design quantities are either the pressure distributions on the blade suction and pressure surfaces or the blade pressure loading and its thickness distribution. The design scheme is based on a wall movement approach where the blade walls are modified based on a virtual velocity distribution that would make the current and target momentum fluxes balance on the blade suction and pressure surfaces. The virtual velocity is used to drive the blade geometry towards a steady state shape corresponding to the prescribed quantities. The design method is implemented in a consistent manner into the unsteady Reynolds Averaged Navier-Stokes (RANS) equations, where an arbitrary Lagrangian-Eulerian (ALE) formulation is used and the boundaries of the computational domain can move and deform in any prescribed time-varying fashion to accommodate the blade movement. A cell vertex finite volume method is used for discretizing the governing equations in space and, at each physical time level, integration in pseudotime is performed using an explicit Runge-Kutta scheme, where local time stepping and residual smoothing are used for convergence acceleration. For design calculations, which are inherently unsteady due to blade movement, the time accuracy of the solution is achieved by means of a dual time stepping scheme. An algebraic Baldwin-Lomax model is used for turbulence closure. The flow analysis method is applied to several test cases for steady state internal flow in linear cascades and the results are compared to numerical and experimental data available in the literature. The inverse design method is first validated for three different configurations, namely a parabolic cascade, a subsonic compressor cascade and a transonic impulse turbine cascade, where different choices of the prescribed design variables are used. The usefulness, robustness, accuracy, and flexibility of this inverse method are then demonstrated on the design of an ONERA transonic compressor cascade, a NACA transonic compressor cascade, a highly cambered DFVLR subsonic turbine cascade, and a VKI transonic turbine cascade geometries, which are typical of gas turbine blades used in modern gas turbine engines.
Author: Kasra Daneshkhah
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
An inverse blade design method, applicable to 2D and 3D flow in turbomachinery blading is developed and is implemented for the design of 2D cascades in compressible viscous flow. The prescribed design quantities are either the pressure distributions on the blade suction and pressure surfaces or the blade pressure loading and its thickness distribution. The design scheme is based on a wall movement approach where the blade walls are modified based on a virtual velocity distribution that would make the current and target momentum fluxes balance on the blade suction and pressure surfaces. The virtual velocity is used to drive the blade geometry towards a steady state shape corresponding to the prescribed quantities. The design method is implemented in a consistent manner into the unsteady Reynolds Averaged Navier-Stokes (RANS) equations, where an arbitrary Lagrangian-Eulerian (ALE) formulation is used and the boundaries of the computational domain can move and deform in any prescribed time-varying fashion to accommodate the blade movement. A cell vertex finite volume method is used for discretizing the governing equations in space and, at each physical time level, integration in pseudotime is performed using an explicit Runge-Kutta scheme, where local time stepping and residual smoothing are used for convergence acceleration. For design calculations, which are inherently unsteady due to blade movement, the time accuracy of the solution is achieved by means of a dual time stepping scheme. An algebraic Baldwin-Lomax model is used for turbulence closure. The flow analysis method is applied to several test cases for steady state internal flow in linear cascades and the results are compared to numerical and experimental data available in the literature. The inverse design method is first validated for three different configurations, namely a parabolic cascade, a subsonic compressor cascade and a transonic impulse turbine cascade, where different choices of the prescribed design variables are used. The usefulness, robustness, accuracy, and flexibility of this inverse method are then demonstrated on the design of an ONERA transonic compressor cascade, a NACA transonic compressor cascade, a highly cambered DFVLR subsonic turbine cascade, and a VKI transonic turbine cascade geometries, which are typical of gas turbine blades used in modern gas turbine engines.
Author: Benedikt Roidl
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Author: Temesgen Teklemariam Mengistu
Publisher:
ISBN:
Category : Aerodynamics
Languages : en
Pages : 0
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Book Description
Aerodynamic shape optimization of gas turbine blades is a very challenging task, given e.g. the flow complexity, the stringent performance requirements, the structural and manufacturing constraints, etc ... This work addresses the challenge by automating the optimization process through the development, implementation and integration of state-of-the-art shape parametrization, numerical optimization methods, Computational Fluid Dynamics (CFD) algorithms and computer architectures. The resulting scheme is successfully applied to single and multi-point aerodynamic shape optimization of several cascades involving two-dimensional transonic and subsonic, viscous and inviscid flow in compressor and turbine cascades. The optimization objective is to achieve a better aerodynamic performance, subject to aerodynamic and structural constraints, over the full operating range of gas turbine cascades by varying the blade profile. That profile is parameterized using a Non-Uniform Rational B-Splines (NURBS) representation, which is flexible accurate and capable of representing the blade profiles with a relatively small number of control points for a given tolerance. The NURBS parameters are then used as design variables in the optimization process. The optimization objective is determined from simulating the flow using an in-house CFD code that solves the two-dimensional Reynolds-Averaged Navier-Stokes (or Euler) equations using a cell-vertex finite volume method on an unstructured triangular mesh and turbulence is modeled using the Baldwin-Lomax model. To save computing time significantly, Artificial Neural Network (ANN) is used to build a low fidelity model that approximates the optimization objective and constraints. Moreover, to reduce the computing wall-clock time, the optimization scheme was parallelized on an SGI ALTIX 3700 machine using Message Passing Interface (MPI), resulting in a parallelization efficiency of almost 100%. Different numerical optimization methods (genetic algorithm, simulated annealing and sequential quadratic programming) were developed, tested and implemented for the different parts of this work. The present choice of objective function and optimization methodology results in a significant improvement in performance for all the cascades that were optimized, without violating the design constraints. The use of ANN results in a ten-fold speed-up of the design process and the scheme parallelization allows for further reduction of the wall-clock time.
Author: Naixing Chen
Publisher: John Wiley & Sons
ISBN: 0470825014
Category : Science
Languages : en
Pages : 448
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Book Description
Computational Fluid Dynamics (CFD) is now an essential and effective tool used in the design of all types of turbomachine, and this topic constitutes the main theme of this book. With over 50 years of experience in the field of aerodynamics, Professor Naixing Chen has developed a wide range of numerical methods covering almost the entire spectrum of turbomachinery applications. Moreover, he has also made significant contributions to practical experiments and real-life designs. The book focuses on rigorous mathematical derivation of the equations governing flow and detailed descriptions of the numerical methods used to solve the equations. Numerous applications of the methods to different types of turbomachine are given and, in many cases, the numerical results are compared to experimental measurements. These comparisons illustrate the strengths and weaknesses of the methods – a useful guide for readers. Lessons for the design of improved blading are also indicated after many applications. Presents real-world perspective to the past, present and future concern in turbomachinery Covers direct and inverse solutions with theoretical and practical aspects Demonstrates huge application background in China Supplementary instructional materials are available on the companion website Aerothermodynamics of Turbomachinery: Analysis and Design is ideal for senior undergraduates and graduates studying in the fields of mechanics, energy and power, and aerospace engineering; design engineers in the business of manufacturing compressors, steam and gas turbines; and research engineers and scientists working in the areas of fluid mechanics, aerodynamics, and heat transfer. Supplementary lecture materials for instructors are available at www.wiley.com/go/chenturbo
Author: National Aeronautics and Space Adm Nasa
Publisher: Independently Published
ISBN: 9781792948770
Category :
Languages : en
Pages : 32
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Book Description
In the two papers on the 'Theory of Blade Design for Large Deflections' published in 1984, a new inverse design technique was presented for designing the shape of turbomachinery blades in three-dimensional flow. The technique involves the determination of the blade profile from the specification of a distribution of the product of the radius and the pitched averaged tangential velocity (i.e., r bar-V(sub theta), the mean swirl schedule) within the bladed region. This is in contrast to the conventional inverse design technique for turbomachinery blading in two dimensional flow in which the blade surface pressure or velocity distribution is specified and the blade profile determined as a result; this is feasible in two-dimensional flow because the streamlines along the blade surfaces are known a priori. However, in three-dimensional flow, the stream surface is free to deform within the blade passage so that the streamlines on the blade surfaces are not known a priori; thus it is difficult and not so useful to prescribe the blade surface pressure or velocity distribution and determine the resulting blade profile. It therefore seems logical to prescribe the swirl schedule within the bladed region for designing a turbomachinery blade profile in three-dimensional flow. Furthermore, specifying r bar-V(sub theta) has the following advantages: (1) it is related to the circulation around the blade (i.e., it is an aerodynamic quantity); (2) the work done or extracted is approximately proportional to the overall change in r bar-V(sub theta) across a given blade row (Euler turbine equation); and (3) the rate of change of r bar-V(sub theta) along the mean streamline at the blade is related to the pressure jump across the blade and therefore the blade loading. Since the publications of those two papers, the technique has been applied to the design of a low speed as well as a high speed radial inflow turbine (for turbocharger applications) both of which showed definite improvements...
Author: Rene Van den Braembussche
Publisher: John Wiley & Sons
ISBN: 1119424097
Category : Technology & Engineering
Languages : en
Pages : 418
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Book Description
A comprehensive overview of fluid dynamic models and experimental results that can help solve problems in centrifugal compressors and modern techniques for a more efficient aerodynamic design. Design and Analysis of Centrifugal Compressors isacomprehensive overview of the theoretical fluid dynamic models describing the flow in centrifugal compressors and the modern techniques for the design of more efficient centrifugal compressors. The author — a noted expert in the field, with over 40 years of experience — evaluates relevant numerical and analytical prediction models for centrifugal compressors with special attention to their accuracy and limitations. Relevant knowledge from the last century is linked with new insights obtained from modern CFD. Emphasis is to link the flow structure, performance and stability to the geometry of the different compressor components. Design and Analysis of Centrifugal Compressors is an accessible resource that combines theory with experimental data and previous research with recent developments in computational design and optimization. This important resource Covers the basic information concerning fluid dynamics that are specific for centrifugal compressors and clarifies the differences with axial compressors Provides an overview of performance prediction models previously developed in combination with extra results from research conducted by the author Describes helpful numerical and analytical models for the flow in the different components in relation to flow stability, operating range and performance Includes the fundamental information for the aerodynamic design of more efficient centrifugal compressors Explains the use of computational fluid dynamics (CFD) for the design and analysis of centrifugal compressors Written for engineers, researchers and designers in industry as well as for academics specializing in the field, Design and Analysis of Centrifugal Compressors offers an up to date overview of the information needed for the design of more effective centrifugal compressors.
Author: Y. L. Lang
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Presented at the International Gas Turbine & Aeroengine Congress & Exhibition, Orlando, FL, Jun 2 - Jun 5, 1997.
Author:
Publisher:
ISBN:
Category : Fluid dynamics
Languages : en
Pages : 610
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Author: Robin Elder
Publisher: John Wiley & Sons
ISBN: 9781860583537
Category : Science
Languages : en
Pages : 258
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Book Description
In the past Computational Fluid Dynamics (CFD) was confined to large organisations capable of developing and supporting their own codes. But recently there has been a rapid increase in the availability of reasonably priced commercial codes, and many more industrial organisations are now able to routinely use CFD. Advances of CFD in Fluid Machinery Design provide the perfect opportunity to find out what industry is doing and this book addresses how CFD is now being increasingly used in the design process, rather than as a post-design analysis tool. COMPLETE CONTENTS Trends in industrial use of CFD Challenges and methodologies in the design of axial flow fans for high-bypass-ratio, gas turbine engines using steady and unsteady CFD A three-dimensional inverse method based on pressure loading for the design of turbomachinery blades Application of CFD to the design and analysis of axial and centrifugal fans and compressors The design and performance of a transonic flow deswirling system – an application of current CFD design techniques tested against model and full-scale experiments Recent developments in unsteady flow modelling for turbomachinery aeroelasticity Computational investigation of flow in casing treatments for stall delay in axial flow fans Use of CFD for the three-dimensional hydrodynamic design of vertical diffuser pumps Recommendations to designers for CFD pump impeller and diffuser simulations Three dimensional CFD – a possibility to analyse piston pump flow dynamics CFD analysis of screw compressor performance Prediction of aerothermal phenomena in high-speed discstator systems Use of CFD in the design of a shaft seal for high-performance turbomachinery Users and potential users, of CFD for the design of fluid machinery, managers, designers, and researchers working in the field of ‘industrial flows’, will all find Advances of CFD in Fluid Machinery Design a valuable volume discussing state-of-the-art developments in CFD.
Author: Araz Arbabi
Publisher:
ISBN:
Category :
Languages : en
Pages : 137
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Book Description
An aerodynamic inverse shape design of turbomachinery blading in three-dimensional viscous flow is developed and implemented into a commercial CFD program, namely ANSYS-CFX. The design method is based on specifying one blade parameter, the stacking condition that is a line from hub to tip, and two other flow parameters these can be a- a target pressure distribution over the blade suction surface (or a target pressure loading) and a blade thickness distribution, b- or target pressure distributions on pressure and suction surfaces. This inverse design approach is fully consistent with the viscous flow assumption and is independent of the CFD approach taken. The blade walls are assumed to be moving with a virtual velocity that would asymptotically drive the blade to the shape that would correspond to the specified target pressure distribution. This virtual velocity distribution is computed from the difference between the computed and the target pressure distributions. The wall displacement is computed in a Junction Box Routine and communicated to ANSYS-CFX using CFX Expression Language and User Defined Functions at each design step. In ANSYS-CFX, an element based finite volume formulation is used for space discretization. The Arbitrary Lagrangian-Eulerian formulation of the unsteady Reynolds-Averaged Navier Stokes (URANS) equations is solved in a time accurate fashion with the blade motion being the source of unsteadiness. At each time step, the blade shape is modified and dynamic meshing is used to remesh the fluid flow domain. The implementation is first validated on a transonic rotor blade; the capability, robustness and accuracy of the method in satisfying the design target are then assessed on a single subsonic stator blade row, the rotor blade of an axial compressor stage and, the rotor and stator blades of an axial turbine stage where different choices of the design variables are used. The method is finally implemented to the redesign of a transonic compressor stage, a subsonic axial compressor stage and a turbine stage so as to improve their aerodynamic performance.
