• Title/Summary/Keyword: Optimization design

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Study on Aerodynamic Optimization Design Process of Multistage Axial Turbine

  • Zhao, Honglei;Tan, Chunqing;Wang, Songtao;Han, Wanjin;Feng, Guotai
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2008.03a
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    • pp.130-135
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    • 2008
  • An aerodynamic optimization design process of multistage axial turbine is presented in this article: first, applying quasi-three dimensional(Q3D) design methods to conduct preliminary design and then adopting modern optimization design methods to implement multistage local optimization. Quasi-three dimensional(Q3D) design methods, which mainly refer to S2 flow surface direct problem calculation, adopt the S2 flow surface direct problem calculation program of Harbin Institute of Technology. Multistage local optimization adopts the software of Numeca/Design3D, which jointly adopts genetic algorithm and artificial neural network. The major principle of the methodology is that the successive design evaluation is performed by using an artificial neural network instead of a flow solver and the genetic algorithms may be used in an efficient way. Flow computation applies three-dimensional viscosity Navier Stokes(N-S) equation solver. Such optimization process has three features: (i) local optimization based on aerodynamic performance of every cascade; (ii) several times of optimizations being performed to every cascade; and (iii) alternate use of coarse grid and fine grid. Such process was applied to optimize a three-stage axial turbine. During the optimization, blade shape and meridional channel were respectively optimized. Through optimization, the total efficiency increased 1.3% and total power increased 2.4% while total flow rate only slightly changed. Therefore, the total performance was improved and the design objective was achieved. The preliminary design makes use of quasi-three dimensional(Q3D) design methods to achieve most reasonable parameter distribution so as to preliminarily enhance total performance. Then total performance will be further improved by adopting multistage local optimization design. Thus the design objective will be successfully achieved without huge expenditure of manpower and calculation time. Therefore, such optimization design process may be efficiently applied to the aerodynamic design optimization of multistage axial turbine.

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Multi-Objective Fuzzy Optimization of Structures (구조물에 대한 다목적퍼지최적화)

  • Park, Choon-Wook;Pyeon, Hae-Wan;Kang, Moon-Myung
    • Journal of Korean Society of Steel Construction
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    • v.12 no.5 s.48
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    • pp.503-513
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    • 2000
  • This study treats the criteria, considering the fuzziness occurred by optimization design. And we applied two weighting methods to show the relative importance of criteria. This study develops multi-objective optimization programs implementing plain stress analysis by FEM and discrete optimization design uniformaly. The developed program performs a sample design of 10-member steel truss. This study can carry over the multi-objective optimization based on total system fuzzy-genetic algorithms while performing the stress analysis and optimization design. Especially, when general optimization with unreliable constraints is cannot be solve this study can make optimization design closed to realistic with fuzzy theory.

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A Study on the Optimized Design of Structures Considering Reliability Analysis (신뢰성을 고려한 구조물의 최적설계에 관한 연구)

  • Park, Hyun-Jung;Shin, Soo-Mi
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.7 no.4
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    • pp.217-224
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    • 2003
  • The objective of this paper is to suggest the technique of program to perform structural optimization design after reliability analysis to consider the uncertainties of structural reponses. AFOSM method is used for reliability analysis then, structural optimization design is developed for 10-bar truss and 3 span 10 stories planar frame model is subject to reliability indices and probability of failure by reliability analysis. SQP method is used for optimization design method, this method has many attractions. As a result of analyzing with having and not having constraints and uncertainty, the minimum weight of truss and planar frame increased respectively 20.92% and average 8.08%.

The Optimization Design of Multiple Access Point placement for wireless LAN (무선 LAN에서 다중 Access Point 위치의 최적화 설계)

  • Lim, Guk-Chan;Kang, Alberto;Choi, Sung-Hun
    • Proceedings of the IEEK Conference
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    • 2002.06a
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    • pp.371-374
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    • 2002
  • The optimal AP placement for wireless LAN is important factor for improving service quality and reducing cost. Logical area property, which is user's frequently posed place, must be considerated for flexible design. This paper proposes optimal multiple AP placement method based on path loss model which is one of radio prediction tool. The proposed method can got flexibility in multiple AP placement using user's defined parameter and tile optimization design uses Hopfield network algorithm The result of simulation shows that the proposed optimization design of multiple AP placement can improve service quality for wireless LAN.

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Parameter Optimal Choice of Claw Pole Alternator based on Iron Loss Model

  • Bao, Xiaohua;Wei, Qiong;Wu, Feng;Li, Jiaqing
    • Journal of international Conference on Electrical Machines and Systems
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    • v.2 no.3
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    • pp.260-268
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    • 2013
  • Based on classical Berotti discrete iron loss calculation model, the iron loss analysis mathematical model of alternator was proposed in this paper. Considering characteristics of high speed and changing frequency of the alternator, Maxwell 3-D model was built to analyze iron loss corresponding to each running speed in alternator. Based on iron loss model of alternator at rated speed, the rotor claw pole size was made an optimization design. The optimization results showed that alternator's output performance had been improved. A new idea was explored in size optimization design of claw pole alternator.

A Design Study of Aerodynamic Noise Reduction In Centrifugal Compressor Part II . Low-noise Optimization Design (원심압축기의 공력소음 저감에 관한 설계연구 Part II : 저소음 최적설계)

  • 선효성;이수갑
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.14 no.10
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    • pp.939-944
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    • 2004
  • The numerical methods including the performance analysis and the noise prediction of the centrifugal compressor impeller are coupled with the optimization design skill, which consists of response surface method, statistical approach, and genetic algorithm. The flow-field Inside of a centrifugal compressor is obtained numerically by solving Wavier-Stokes equations. and then the propagating noise is estimated from the distributed surface pressure by using Ffowcs Williams-Hawkings formulation. The quadratic response surface model with D-optimal 3-level factorial experimental design points is constructed to optimize the impeller geometry for the advanced centrifugal compressor. The statistical analysis shows that the quadratic model exhibits a reasonable fitting quality resulting in the impeller blade design with high performance and low far-field noise level. The influences of selected design variables, objective functions, and constraints on the impeller performance and the impeller noise are also examined as a result of the optimization process.

Topology Optimization Design of Machine Tools Head Frame Structures for the Machining of Aircraft Parts (항공기부품가공용 공작기계 헤드프레임 구조의 위상최적화 설계)

  • Yun, Taewook;Lee, Seoksoon
    • Journal of Aerospace System Engineering
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    • v.12 no.4
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    • pp.18-25
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    • 2018
  • The head frame structure of a machine tool for aircraft parts, which requires machining precision and machining of difficult-to-cut materials is required to be light-weighted for precision high-speed machining and to minimize possible deformation by cutting force. To achieve high stiffness and for light-weight structure optimization design, a preliminary model was designed based on finite element analysis. The topology optimization design of light-weight, high stiffness, and low vibration frame structure were performed by minimizing compliance. As a result, the frame weight decreased by 17.3%, the maximum deflection was less than 0.007 mm, and the natural frequency increased by 30.6%. The static stiffness was increased in each axis direction and the dynamic stiffness exhibited contrary results according to the axis. Optimized structure with the high stiffness of low vibration in topology optimization design was confirmed.