scholarly journals Automated Design Optimization of a Mono Tiltrotor in Hovering and Cruising States

Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1155
Author(s):  
Lifang Zeng ◽  
Jianxin Hu ◽  
Dingyi Pan ◽  
Xueming Shao
Keyword(s):  
Design Parameters ◽  
Optimization Approach ◽  
Optimized Design ◽  
Multi Objective Optimization ◽  
Optimal Point ◽  
Propulsive Efficiency ◽  
Multi Objective ◽  
Coaxial Rotor ◽  
Design Variables ◽  
Single Objective

A mono tiltrotor (MTR) design which combines concepts of a tiltrotor and coaxial rotor is presented. The aerodynamic modeling of the MTR based on blade element momentum theory (BEMT) is conducted, and the method is fully validated with previous experimental data. An automated optimization approach integrating BEMT modeling and optimization algorithms is developed. Parameters such as inter-rotor spacing, blade twist, taper ratio and aspect ratio are chosen as design variables. Single-objective (in hovering or in cruising state) optimizations and multi-objective (both in hovering and cruising states) optimizations are studied at preset design points; i.e., hovering trim and cruising trim. Two single-objective optimizations result in different sets of parameter selections according to the different design objectives. The multi-objective optimization is applied to obtain an identical and compromised selection of design parameters. An optimal point is chosen from the Pareto front of the multi-objective optimization. The optimized design has a better performance in terms of the figure of merit (FM) and propulsive efficiency, which are improved by 7.3% for FM and 13.4% for propulsive efficiency from the prototype, respectively. Further aerodynamic analysis confirmed that the optimized rotor has a much more uniform load distribution along the blade span, and therefore a better aerodynamic performance in both hovering and cruising states is achieved.

A Parametric Optimization Approach of an Induction Heating System for Energy Consumption Reduction

2017 ◽  
Author(s):  
Paolo Cicconi ◽  
Anna Costanza Russo ◽  
Mariorosario Prist ◽  
Francesco Ferracuti ◽  
Michele Germani ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Induction Heating ◽  
Heating System ◽  
High Energy ◽  
Design Parameters ◽  
Optimization Approach ◽  
Multi Objective Optimization ◽  
Molding Process ◽  
Multi Objective ◽  
Induction Heating System

Nowadays, electromagnetic high-frequency induction is very used for different non-contact heating applications such as the molding process. Every molding process requires the preheating and the thermal maintenance of the molds, to enhance the filling phase and the quality of the final products. In this context, an induction heating system, mostly, is a customized equipment. The design and definition of an induction equipment depends on the target application. This technology is highly efficient and performant, however it provides a high-energy consumption. Therefore, optimization strategies are very suitable to reduce energy cost and consumption. The proposed paper aims to define a method to optimize the induction heating of a mold in terms of time, consumption, and achieved temperature. The proposed optimization method involves genetic algorithms to define the design parameters related to geometry and controller. A test case describes the design of an induction heating system for a polyurethane molding process, which is the soles foaming. This case study deals with the multi-objective optimization of parameters such as the geometrical dimensions, the inductor sizing, and the controller setting. The multi-objective optimization aims to reduce the energy consumption and to increase the wall temperature of the mold.

The Application of Entransy Dissipation Theory in Optimization Design of Heat Exchanger

2010 ◽  
Author(s):  
Jiangfeng Guo ◽  
Mengxun Li ◽  
Mingtian Xu ◽  
Lin Cheng
Keyword(s):  
Heat Conduction ◽  
Heat Exchanger ◽  
Working Fluid ◽  
Optimization Approach ◽  
Entransy Dissipation ◽  
Multi Objective Optimization ◽  
Fluid Friction ◽  
Multi Objective ◽  
Heat Exchanger Design ◽  
Single Objective

The heat conduction and fluid friction are two main detrimental irreversibilities in heat exchanger. According to the entransy dissipation theory, the entransy dissipation can be employed to quantify these two irreversibilities. In the present work, the optimization of heat exchanger design is investigated by applying the entransy dissipation theory and genetic algorithm. Firstly, by taking the total dimensionless entransy dissipation caused by heat conduction and fluid friction as objective function, a single-objective optimization approach to heat exchanger design is developed. However, it is found that the role played by the fluid friction is not fully taken into account in this approach when the working fluid of heat exchanger is liquid. In order to circumvent this problem, the non-dimensional entransy dissipations associated with heat conduction and fluid friction are taken as two separate objective functions and a multi-objective optimization approach to heat exchanger design is established. In comparison with the single-objective optimization approach, the multi-objective optimization approach demonstrates more advantages and flexibilities for heat exchanger design.

A Genetic Algorithm Based Multi-Objective Optimization of Squealer Tip Geometry in Axial Flow Turbines: A Constant Tip Gap Approach

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
H. Maral ◽  
C. B. Şenel ◽  
K. Deveci ◽  
E. Alpman ◽  
L. Kavurmacıoğlu ◽  
...  
Keyword(s):  
Genetic Algorithm ◽  
Tip Clearance ◽  
Design Parameters ◽  
Leakage Flow ◽  
Optimization Approach ◽  
Multi Objective Optimization ◽  
Tip Leakage Flow ◽  
Tip Leakage ◽  
Multi Objective ◽  
Blade Tip

Abstract Tip clearance is a crucial aspect of turbomachines in terms of aerodynamic and thermal performance. A gap between the blade tip surface and the stationary casing must be maintained to allow the relative motion of the blade. The leakage flow through the tip gap measurably reduces turbine performance and causes high thermal loads near the blade tip region. Several studies focused on the tip leakage flow to clarify the flow-physics in the past. The “squealer” design is one of the most common designs to reduce the adverse effects of tip leakage flow. In this paper, a genetic-algorithm-based optimization approach was applied to the conventional squealer tip design to enhance aerothermal performance. A multi-objective optimization method integrated with a meta-model was utilized to determine the optimum squealer geometry. Squealer height and width represent the design parameters which are aimed to be optimized. The objective functions for the genetic-algorithm-based optimization are the total pressure loss coefficient and Nusselt number calculated over the blade tip surface. The initial database is then enlarged iteratively using a coarse-to-fine approach to improve the prediction capability of the meta-models used. The procedure ends once the prediction errors are smaller than a prescribed level. This study indicates that squealer height and width have complex effects on the aerothermal performance, and optimization study allows to determine the optimum squealer dimensions.

Multi-objective Optimization of a Flexible Rotor in Magnetic Bearings With Critical Speeds and Control Current Constraints

1997 ◽  
Vol 119 (1) ◽  
pp. 186-195 ◽  
Author(s):  
Ting Nung Shiau ◽  
Chun Pao Kuo ◽  
Jiunn Rong Hwang
Keyword(s):  
Expansion Method ◽  
Magnetic Bearings ◽  
Multi Objective Optimization ◽  
Flexible Rotor ◽  
Weighting Method ◽  
Cross Sectional ◽  
Critical Speeds ◽  
Multi Objective ◽  
Design Variables ◽  
Single Objective

This paper presents the single objective optimization and the multi-objective optimization for a flexible rotor system with magnetic bearings. The weight of rotor shaft and the transmitted forces at the magnetic bearings are minimized either individually or simultaneously under the constraints on the critical speeds and the control currents of magnetic bearings. The design variables are the cross-sectional area of the shaft, the bias currents of magnetic bearings, and the positions of the disk and the magnetic bearings. The dynamic characteristics are analyzed using the generalized polynomial expansion method and the sensitivity analysis is also studied. For single objective optimization, the method of feasible directions (MFD) is applied. For multi-objective optimization, the weighting method (WM), the goal programming method (GPM), and the fuzzy method (FM) are employed. It is found that the system design can be significantly affected by the choices of the bias currents of magnetic bearings, the position of the disk with unbalance, and the magnetic bearings. The results also show that a better compromised design can always be obtained for multi-objective optimization.

Constrained Multi-Objective Optimization of a Hydraulic Flywheel Accumulator

2013 ◽  
Author(s):  
Kyle G. Strohmaier ◽  
James D. Van de Ven
Keyword(s):  
Energy Storage ◽  
Design Parameters ◽  
Optimization Approach ◽  
Total System ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Important Means ◽  
Energy Independence ◽  
Hydraulic Accumulator ◽  
Velocity Constraints

Improving energy storage technology is an important means of addressing concerns over fossil fuel scarcity and energy independence. Traditional hydraulic accumulator energy storage, though favorable in power density, durability, cost, and environmental impact, suffers from relatively low energy density and a pressure-dependent state of charge. The hydraulic flywheel accumulator concept utilizes both pneumatic and kinetic energy domains by employing a rotating pressure vessel. This paper describes a mathematical model of the hydraulic flywheel accumulator and presents the results of a multi-objective optimization of the associated design parameters. The two optimization objectives are to minimize the total system mass and minimize the total energy converted between the pneumatic and kinetic domains during operation. These objectives are pursued by varying five design parameters: accumulator radius, wall thickness, and length; end cap length; and maximum angular velocity. Constraints on combinations of these design parameters are imposed by material stress, as well as the energy capacity required to complete a specified drive cycle. This optimization approach can be used to guide the design of a hydraulic flywheel accumulator for a variety of different applications.

Multi-objective TMA management optimization using the point merge system

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ramazan Kursat Cecen
Keyword(s):  
Mathematical Model ◽  
Mixed Integer ◽  
Optimization Approach ◽  
Multi Objective Optimization ◽  
Content Type ◽  
Multi Objective ◽  
First Come First Serve ◽  
Management Optimization ◽  
The Mathematical Model ◽  
Single Objective

Purpose The purpose of this study is to provide conflict-free operations in terminal manoeuvre areas (TMA) using the point merge system (PMS), airspeed reduction (ASR) and ground holding (GH) techniques. The objective is to minimize both total aircraft delay (TD) and the total number of the conflict resolution manoeuvres (CRM). Design/methodology/approach The mixed integer linear programming (MILP) is used for both single and multi-objective optimization approaches to solve aircraft sequencing and scheduling problem (ASSP). Compromise programming and ε-constraint methods were included in the methodology. The results of the single objective optimization approach results were compared with baseline results, which were obtained using the first come first serve approach, in terms of the total number of the CRM, TD, the number of aircraft using PMS manoeuvres, ASR manoeuvres, GH manoeuvres, departure time updates and on-time performance. Findings The proposed single-objective optimization approach reduced both the CRM and TD considerably. For the traffic flow rates of 15, 20 and 25 aircraft, the improvement of CRM was 53.08%, 41.12% and 32.6%, the enhancement of TD was 54.2%, 48.8% and 31.06% and the average number of Pareto-optimal solutions were 1.26, 2.22 and 3.87, respectively. The multi-objective optimization approach also exposed the relationship between the TD and the total number of CRM. Practical implications The proposed mathematical model can be implemented considering the objectives of air traffic controllers (ATCOs) and airlines operators. Also, the mathematical model is able to create conflict-free TMA operations and, therefore, it brings an opportunity for ATCOs to reduce frequency occupancy time. Originality/value The mathematical model presents the total number of CRM as an objective function in the ASSP using the MILP approach. The mathematical model integrates ATCOs’ and airline operators’ perspective together with new objective functions.

scholarly journals Multiobjective Optimization of a Flexible Rotor in Magnetic Bearings With Critical Speeds and Control Current Constraints

1994 ◽  
Author(s):  
Ting Nung Shiau ◽  
Chun Pao Kuo ◽  
Jiunn Rong Hwang
Keyword(s):  
Expansion Method ◽  
Magnetic Bearings ◽  
Multi Objective Optimization ◽  
Flexible Rotor ◽  
Weighting Method ◽  
Cross Sectional ◽  
Critical Speeds ◽  
Multi Objective ◽  
Design Variables ◽  
Single Objective

This paper presents the single objective optimization and the multi-objective optimization for a flexible rotor system with magnetic bearings. The weight of rotor shaft and the transmitted forces at the magnetic bearings are minimized either individually or simultaneously under the constraints on the critical speeds and the control currents of magnetic bearings. The design variables are the cross-sectional area of the shaft, the bias currents of magnetic bearings, and the positions of the disk and the magnetic bearings. The dynamic characteristics are analyzed using the generalized polynomial expansion method and the sensitivity analysis is also studied. For single objective optimization, the method of feasible directions (MFD) is applied. For multi-objective optimization, the methods including the weighting method (WM), goal programming method (GPM), and the fuzzy method (FM) are employed. It is found that the system design can be significantly affected by the choices of the bias currents of magnetic bearings, the position of the disk with unbalance and the magnetic bearings. The results also show that a better compromized design can always be obtained for multi-objective optimization.

Multi-objective optimization approach to reliability-based robust global optimization of electromagnetic device

2013 ◽  
Vol 33 (1/2) ◽  
pp. 191-200 ◽  
Author(s):  
Ziyan Ren ◽  
Dianhai Zhang ◽  
Chang Seop Koh
Keyword(s):  
Design Sensitivity ◽  
Target System ◽  
Stray Field ◽  
Optimization Approach ◽  
Multi Objective Optimization ◽  
The Finite Element Method ◽  
Content Type ◽  
Multi Objective ◽  
Reliability Based Design ◽  
Design Variables

Purpose – The purpose of this paper is to propose a multi-objective optimization algorithm, which can improve both the performance robustness and the constraint feasibility when the uncertainty in design variables is considered. Design/methodology/approach – Multi-objective robust optimization by gradient index combined with the reliability-based design optimization (RBDO). Findings – It is shown that searching for the optimal design of the TEAM problem 22, which can minimize the magnetic stray field by keeping the target system energy (180 MJ) and improve the feasibility of superconductivity constraint (quenching condition), is possible by using the proposed method. Originality/value – RBDO method applied to the electromagnetic problem cooperated with the design sensitivity analysis by the finite element method.

Design Optimization of 2TPS/2TPR Parallel Manipulator Based on GA

2013 ◽  
Vol 568 ◽  
pp. 163-168
Author(s):  
Y.M. Wang ◽  
H.J. San ◽  
L. Jiang
Keyword(s):  
Design Optimization ◽  
Parallel Manipulator ◽  
Optimal Size ◽  
Optimized Design ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Design Variables

4-DOF asymmetric parallel manipulator 2TPS /2TPR is researched in this paper. Firstly, the structure of 2TPS /2TPR is described in detail. Optimized design variables and constraints are sure. Then multi-objective optimization is built by flexibility and workspace of structure. Finally, design optimization of 2TPS/2TPR parallel manipulator based on GA. The optimal size combination of 2TPS /2TPR parallel manipulator is got.

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