Adjoint-Based Multidisciplinary, Multipoint Optimization of a Radial Turbine Considering Aerodynamic and Structural Performances

2019 ◽  
Author(s):  
Lasse Mueller ◽  
Tom Verstraete ◽  
Marc Schwalbach
Keyword(s):  
Mechanical Stresses ◽  
Programming Algorithm ◽  
Navier Stokes ◽  
Analysis Tool ◽  
Element Analysis ◽  
Turbine Efficiency ◽  
Radial Turbine ◽  
Design Variables ◽  
Gradient Based ◽  
Adjoint Approach

Abstract This paper presents a multidisciplinary adjoint-based design optimization of a turbocharger radial turbine for automotive applications. The aim is to improve the total-to-static efficiency of the turbine while keeping mechanical stresses below a predefined limit. The search for the optimal design is accomplished using an efficient Sequential Quadratic Programming algorithm considering additional aerodynamic and manufacturing constraints. The aerodynamic performance of the wheel is evaluated by a Reynolds-Averaged Navier-Stokes solver, whereas the maximum stresses in the material are predicted by a Finite Element Analysis tool. The design gradients required by the optimizer are computed with the adjoint approach which provides sensitivity information largely independent of the number of design variables. The results presented in this paper show the clear need to take into account mechanical stresses during optimization, as they are the most restrictive design limitation. However, the gradient-based optimization algorithm is able to effectively keep the stress levels below the critical value while significantly improving the turbine efficiency in a few design cycles.

A Comparative Study of Optimisation Methods for Aerodynamic Design of Turbomachinery Blades

2000 ◽  
Author(s):  
Shahrokh Shahpar
Keyword(s):  
Stokes Equations ◽  
Guide Vane ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Analysis Tool ◽  
Geometrical Constraints ◽  
Gradient Based ◽  
Turbomachinery Blades ◽  
Optimisation Methods ◽  
Nozzle Guide

A new approach to three-dimensional design of turbomachinery blades is presented. A number of heuristic and gradient based optimisers are used in conjunction with a linear sensitivity analysis tool, FAITH, to re-design a turbine nozzle guide vane. A novel linear approach is used to eliminate the large computational costs usually associated with function evaluations which are essentially solutions to the Navier-Stokes equations. Results are compared with those obtained previously from the inverse design mode of FAITH. With the present approach, it is shown that nonlinear complicated cost functions can be reduced significantly and aerodynamic and geometrical constraints can be handled easily and efficiently.

CAD-Based Adjoint Optimization of the Stresses in a Radial Turbine

2017 ◽  
Author(s):  
Tom Verstraete ◽  
Lasse Müller ◽  
Jens-Dominik Müller
Keyword(s):  
Structural Model ◽  
Computational Cost ◽  
Test Case ◽  
Analysis Tool ◽  
Full Potential ◽  
Cad Model ◽  
Stress Concentrations ◽  
Radial Turbine ◽  
Gradient Based ◽  
Von Mises

The design optimization of turbomachinery components has witnessed an increased attention in last decade, and is currently used in many companies in the daily design cycle. The adjoint method proves to have the highest potential in this field, however, has still two major shortcomings before its full potential can be used: 1) the shape is mainly parameterized by its grid and the connection to the CAD model is lost, and 2) the optimization process includes only aerodynamic performance and neglects stress and vibration requirements. Within this paper a methodology is developed to include stress calculations into a gradient-based framework, which requires the differentiation of a stress analysis tool. To allow combining the sensitivities from the structural model with those from the aero performance, the CAD model is used for parameterizing the shape, effectively defining a parametrization that controls both the fluid and solid domain that remain linked to each other without creating voids between both models. The method is tested on a radial turbine test case in which the meridional layout is optimized to reduce the maximum von Mises stresses in the material. The results demonstrate a significant reduction in stress concentrations with a limited computational cost.

scholarly journals Adjoint-Based Multi-Point and Multi-Objective Optimization of a Turbocharger Radial Turbine

2019 ◽  
Vol 4 (2) ◽  
pp. 10 ◽  
Author(s):  
Lasse Mueller ◽  
Tom Verstraete
Keyword(s):  
Computational Cost ◽  
Meridional Flow ◽  
Optimal Designs ◽  
Programming Algorithm ◽  
Turbine Wheel ◽  
Radial Turbine ◽  
Trade Offs ◽  
Order Of Magnitude ◽  
Gradient Based ◽  
The Moment

This paper presents a gradient-based design optimization of a turbocharger radial turbine for automotive applications. The aim is to improve both the total-to-static efficiency and the moment of inertia of the turbine wheel. The search for the optimal designs is accomplished by a high-fidelity adjoint-based optimization framework using a fast sequential quadratic programming algorithm. The proposed method is able to produce improved Pareto-optimal designs, which are trade-offs between the two competing objectives, in only a few iterations. This is realized by redesigning the blade shape and the meridional flow channel for the respective target while satisfying imposed aerodynamic constraints. Furthermore, a comparative study with an evolutionary algorithm suggests that the gradient-based method has found the global Pareto front at a computational cost which is about one order of magnitude lower.

scholarly journals Analysis and Design of PMBLDC Motor for Three Wheeler Electric Vehicle Application

2019 ◽  
Vol 87 ◽  
pp. 01022
Author(s):  
V. Sandeep ◽  
Sharankumar Shastri
Keyword(s):  
Permanent Magnet ◽  
Analysis Tool ◽  
Element Analysis ◽  
Analysis And Design ◽  
Brushless Dc ◽  
Design Variables ◽  
Radial Flux ◽  
Electromagnetic Characteristics ◽  
Permanent Magnet Brushless Dc ◽  
Analytical Tools

This paper deals with analysis and design of permanent magnet brushless dc machine (PMBLDCM), primarily aimed for three wheeler applications. The motor sizing accounts for the forces acting on the motor and the design variables such as number of stator and rotor slots, stator and rotor dimensioning, air-gap approximation, slot sizing, flux per pole and permanent magnet sizing has been explained using simplified equations. The designed motor rated at 1.5 kW, 3000 rpm, 120 V radial flux surface mounted permanent magnet rotor, is then assessed using analytical tools for design such as ANSYS’s RMXprt to verify the analytically obtained results. These results are then verified using the computer aided analysis tool, finite element analysis, using ANSYS Maxwell, to obtain the electromagnetic characteristics of the motor for further modification of design.

Topological and Geometric Synthesis of Compliant Mechanisms

2000 ◽  
Author(s):  
Joel A. Hetrick ◽  
Sridhar Kota
Keyword(s):  
Compliant Mechanisms ◽  
Programming Algorithm ◽  
Design Stage ◽  
Stable Convergence ◽  
Ground Structure ◽  
Element Analysis ◽  
Cross Section Area ◽  
Design Variables ◽  
Section Area ◽  
Geometric Variation

Abstract Structural optimization of compliant mechanisms is a systematic and automated approach for synthesizing the topology (layout) of mechanisms given the motion requirements. Here, two optimization approaches are presented: one employing a traditional full ground structure and one utilizing a modular ground structure whose nodes are allowed to wander within specified ranges. For problems discretized by many elements, the modular ground structure effectively reduces the number of design variables and speeds design convergence. In addition, relocation of node coordinates allows for geometric variation within the topology (layout) design stage. Linear finite element analysis using truss elements is utilized along with a sequential quadratic programming algorithm to optimize the mechanisms. Derivation of an efficiency based objective formulation is presented to determine the optimal mechanism design which satisfies motion requirements while maximizing the transfer of energy through the mechanism. Calculation of design derivatives with respect to element cross-section area and node position is performed using the adjoint variable method which provides faster and more stable convergence over finite difference approaches. Design examples are presented which directly compare the performance of topology optimized designs for the fixed node full ground structure to the floating node modular ground structure.

scholarly journals Experimental Study of Pneumatic Two-Stage Small-Size Radial Turbine

2018 ◽  
Vol 7 (4.38) ◽  
pp. 305
Author(s):  
Yuri Pavlovich Kuznetsov ◽  
Lev Anatolevich Zakharov ◽  
Sergey Nikolaevich Khrunkov ◽  
Artem Aleksandrovich Kraynov ◽  
Aleksandr Evgenevich Zhukov
Keyword(s):  
Experimental Study ◽  
Supersonic Nozzle ◽  
Geometrical Parameters ◽  
Two Stage ◽  
Efficiency Criterion ◽  
Reaction Stage ◽  
Turbine Efficiency ◽  
Radial Turbine ◽  
Design Variables ◽  
Expansion Angle

This work is aimed at experimental study of the influence of design variables of the first jet reaction stage on the properties of pneumatic two-stage small-size radial turbine. Kinematic layout of the considered turbine is presented, operating processes are described, the final target is formulated to reveal the influence of certain geometrical parameters of the first jet reaction stage which determine overall turbine efficiency. Criterion of nozzle efficiency is determined, variable parameters of multifactorial experiment are selected; experimental facility and procedure of data processing are described. The main experimental results are presented. It is established that the greatest influence on the turbine efficiency is exerted by supersonic nozzle expansion angle. Optimum combination of geometrical expansion extent and geometrical expansion angle of supersonic nozzle of the first jet reaction stage of two-stage small-size radial turbine has been experimentally determined.  

Improving Efficiency of a High Work Turbine Using Nonaxisymmetric Endwalls— Part I: Endwall Design and Performance

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
T. Germain ◽  
M. Nagel ◽  
I. Raab ◽  
P. Schüpbach ◽  
R. S. Abhari ◽  
...  
Keyword(s):  
Axial Flow ◽  
Programming Algorithm ◽  
Navier Stokes ◽  
Turbine Efficiency ◽  
Computational Fluid Dynamics Cfd ◽  
Transition Modeling ◽  
And Performance ◽  
High Work ◽  
Sequential Quadratic Programming Algorithm ◽  
Probe Measurements

This paper is the first part of a two part paper reporting the improvement of efficiency of a one-and-half stage high work axial flow turbine by nonaxisymmetric endwall contouring. In this first paper the design of the endwall contours is described, and the computational fluid dynamics (CFD) flow predictions are compared with five-hole-probe measurements. The endwalls have been designed using automatic numerical optimization by means of a sequential quadratic programming algorithm, the flow being computed with the 3D Reynolds averaged Navier-Stokes (RANS) solver TRACE. The aim of the design was to reduce the secondary kinetic energy and secondary losses. The experimental results confirm the improvement of turbine efficiency, showing a stage efficiency benefit of 1%±0.4%, revealing that the improvement is underestimated by CFD. The secondary flow and loss have been significantly reduced in the vane, but improvement of the midspan flow is also observed. Mainly this loss reduction in the first row and the more homogeneous flow is responsible for the overall improvement. Numerical investigations indicate that the transition modeling on the airfoil strongly influences the secondary loss predictions. The results confirm that nonaxisymmetric endwall profiling is an effective method to improve turbine efficiency but that further modeling work is needed to achieve a good predictability.

Finite Element Modeling for Steel Cord Analysis in Radial Tires

2013 ◽  
Vol 41 (1) ◽  
pp. 60-79 ◽  
Author(s):  
Wei Yintao ◽  
Luo Yiwen ◽  
Miao Yiming ◽  
Chai Delong ◽  
Feng Xijin
Keyword(s):  
Finite Element ◽  
High Efficiency ◽  
Force Measurement ◽  
Three Dimensional ◽  
Local Stress ◽  
Tension Force ◽  
Center Line ◽  
Element Analysis ◽  
Design Variables ◽  
Steel Cord

ABSTRACT: This article focuses on steel cord deformation and force investigation within heavy-duty radial tires. Typical bending deformation and tension force distributions of steel reinforcement within a truck bus radial (TBR) tire have been obtained, and they provide useful input for the local scale modeling of the steel cord. The three-dimensional carpet plots of the cord force distribution within a TBR tire are presented. The carcass-bending curvature is derived from the deformation of the carcass center line. A high-efficiency modeling approach for layered multistrand cord structures has been developed that uses cord design variables such as lay angle, lay length, and radius of the strand center line as input. Several types of steel cord have been modeled using the developed method as an example. The pure tension for two cords and the combined tension bending under various loading conditions relevant to tire deformation have been simulated by a finite element analysis (FEA). Good agreement has been found between experimental and FEA-determined tension force-displacement curves, and the characteristic structural and plastic deformation phases have been revealed by the FE simulation. Furthermore, some interesting local stress and deformation patterns under combined tension and bending are found that have not been previously reported. In addition, an experimental cord force measurement approach is included in this article.

scholarly journals Use of Dynamic Analysis to Investigate the Behaviour of Short Neutral Sections in the Overhead Line Electrification

2021 ◽  
Vol 6 (5) ◽  
pp. 62
Author(s):  
John Morris ◽  
Mark Robinson ◽  
Roberto Palacin
Keyword(s):  
Dynamic Analysis ◽  
Dynamic Simulation ◽  
Model Simulation ◽  
Analysis Tool ◽  
Overhead Line ◽  
Element Analysis ◽  
Novel Approach ◽  
Section Model ◽  
The Uk ◽  
Neutral Section

The ‘short’ neutral section is a feature of alternating current (AC) railway overhead line electrification that is often unreliable and a source of train delays. However hardly any dynamic analysis of its behaviour has been undertaken. This paper briefly describes the work undertaken investigating the possibility of modelling the behaviour using a novel approach. The potential for thus improving the performance of short neutral sections is evaluated, with particular reference to the UK situation. The analysis fundamentally used dynamic simulation of the pantograph and overhead contact line (OCL) interface, implemented using a proprietary finite element analysis tool. The neutral section model was constructed using physical characteristics and laboratory tests data, and was included in a validated pantograph/OCL simulation model. Simulation output of the neutral section behaviour has been validated satisfactorily against real line test data. Using this method the sensitivity of the neutral section performance in relation to particular parameters of its construction was examined. A limited number of parameter adjustments were studied, seeking potential improvements. One such improvement identified involved the additional inclusion of a lever arm at the trailing end of the neutral section. A novel application of pantograph/OCL dynamic simulation to modelling neutral section behaviour has been shown to be useful in assessing the modification of neutral section parameters.

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