• International Journal of Fluid Machinery and Systems
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• 제3권4호
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• pp.309-314
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• 2010

Stainless steel stamping multistage pump has become the mainstream of civil multi-stage pump. Combined with the technological features of stamping and welding pump, the studies of design for hydraulic parts of pump were come out. An $L_{18}$（$3^7$）orthogonal experiment was designed with seven factors and three values including blade inlet angle, impeller outer diameter, guide vane blade number, etc. 18 plans were designed. The two stage of whole flow field on stainless steel stamping multistage pump at design point for design was simulated by CFD. According to the test result and optimization design with experimental research, the trends of main parameters which affect hydraulic performance were got. After being manufactured and tested, the efficiency of the optimal model pump reaches 61.36% and the single head is more than 4.8 m. Compared with the standard efficiency of 53%, the design of the stainless steel stamping pump is successful. The result would be instructive to the design of Stainless steel stamping multistage pump designed by the impeller head maximum approach.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2011년도 제36회 춘계학술대회논문집
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• pp.397-400
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• 2011

소형 가스터빈 엔진에 장착 가능한 저압단 축류 압축기의 공력성능 및 구조적 안정성을 동시에 고려한 최적화 설계를 수행하였다. 근사모델을 구축하여 유전알고리즘을 이용하여 전역 최적화 해를 도출하였다. 최적 설계된 압축기의 동익단은 Hub쪽에서 날개의 부하가 커지되, Tip쪽에서 입사각이 0에 가깝게 설계되었다. 한편 동익의 형상은 허브쪽에서 사다리꼴 모양으로 수렴이 되어 구조적 안정성을 확보하도록 설계가 되었다. 최종적인 수치해석 결과 작동점에서 동익단의 효율은 87.6%이며 구조적 안정성을 나타내는 안전계수는 3이상을 확보하였다.

• Journal of Ship and Ocean Technology
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• 제11권2호
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• pp.10-25
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• 2007

With the sharp increase of the oil price, the issue of the energy saving requires even higher propulsive efficiency of the propellers. Traditionally the propellers have been designed with the criteria such as that of Lerbs optimum based on the lifting line theory and the empirical formulae of Lerbs and van Manen giving relations of the wake pitch with the wake non-uniformity. With the aid of the high speed computer, it is now possible to apply the time-consuming iterative approaches for the solution of the lifting surface problems. In this paper we formulate the variational problem to optimize the efficiency of the propeller operating in the given ship wake using the lifting surface method. The variational formulation relating the spanwise circulation distribution with the propulsive efficiency to be maximized is however non-linear in circulation distribution functions, thus the iterative method is applied to the quasi-linearized equations. The blade shape design also requires the iterative procedures, because the shape of the blade which is represented by the lifting surface is unknown a priori. The numerical code was validated with the DTNSRDC propeller 4119 which is well-known to be optimum in uniform inflow condition. In addition existing (well-designed) commercial propellers were selected and compared with the results of the open water tests and the self-propulsion tests.

• Composites Research
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• 제35권5호
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• pp.340-346
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• 2022

본 연구에서는 복합재료 블레이드에 대한 최적 구조설계 프레임워크를 구성하고, 이를 헬리콥터 블레이드에 적용하여 최적 구조설계를 수행하였다. 단면 형상의 경우 C형 및 D형 스파를 선택할 수 있게 구성하였으며, 최적설계 프레임워크는 유전자 알고리즘과 입자 군집 최적화 알고리즘을 결합한 PSGA를 활용하였다. 단면의 기하학적 모델링은 B-spline을 이용하여 구현하였고, 유한요소 모델 생성 프로그램 Gmsh를 통해 단면 유한요소모델을 만든 뒤 단면 해석 프로그램인 Ksec2D를 사용하여 구조해석 결과를 도출하였다. 본 최적설계 프레임워크를 HART II 블레이드에 적용하여 최적 구조설계를 수행한 결과, C형 스파 모델은 기준 형상 대비 무게 7.39%, D형 스파 모델은 6.65% 감소하였으며, 이때 전단중심은 모두 공력중심과 인접한(5% 이내) 결과를 도출하였다. 본 연구를 통해 일반적인 헬리콥터 블레이드의 단면에 적용할 수 있는 최적 구조설계 프레임워크의 유효성을 확인하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집C
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• pp.380-385
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• 2001

The paper presents a new multidisciplinary design optimization architecture using optimal sensitivity and coordination of interdisciplinary design variables. Original design problem is decomposed into a number of sub-problems that represent individual engineering analysis. The coupled effects between sub-problems are computed by interdisciplinary design variables. System level coordination is determined by optimal parameter sensitivity calculated by finite difference method. The proposed. MDO strategy is applied to a simplified model of rotorcraft blade design associated with structures and aerodynamic disciplines.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.1100-1103
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• 2007

For the past decade many effort has been delivered to understand noise generation mechanism for the small size engine cooling fan. As a result of that effort, the low noise fan such as the Wave fan was developed. Now the Wave fan becomes the well known low noise engine cooling fan. But in case of the new car development, the system in the new car will be different from previous one. So we need system optimization for every new model. In case of special application, a low speed fan should be developed to match system requirement. In that case, we meet severe engineering requirement by conducting fan system optimization instead of the simple fan scaling. In this paper, I will show you the system optimize process.

• 한국유체기계학회 논문집
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• 제11권3호
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• pp.36-42
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• 2008

In this paper, the performance characteristics of the impeller in a centrifugal pump were investigated using DOE(Design of Experiment) with commercial CFD software. Geometric parameters of vane plane development were defined with the meridional shape and frontal view of the impeller. The incidence angles and the exit blade angle were selected as main parameters using 2k factorial and the influences of selected design parameters were examined through the optimization process using RSM.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년 영문 학술대회
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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.

• 한국항공우주학회지
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• 제33권5호
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• pp.9-17
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• 2005

헬리콥터 초기 설계 단계에서는 형상 변화에 따른 공력 성능 변화를 예측하여 최적의 형상을 결정한다. 덮개꼬리로터에서는 공력성능 개선을 위해 블레이드와 덮개사이의 끝단간극, 블레이드 평면형, 그리고 블레이드 배치의 최적화가 필요하다. 본 연구에서는 비정렬 격자에 기초한 비점성 압축성 로터 유동 해석 코드를 이용하여 설계 초기 기본형상의 덮개꼬리로터에 대해 끝단간극, 블레이드 평면형, 그리고 블레이드 배치 등의 형상변화에 따른 공력 성능을 예측하고 그 특성을 파악하였다.

• 대한기계학회논문집B
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• 제28권1호
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• pp.16-23
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• 2004

Acoustic characteristics of unbaffled and baffled combustion chamber are experimentally investigated under atmospheric condition to preliminarily determine baffle for mitigation of combustion instability. To investigate the effect of the baffle which has several configurations such as radial baffles and hub/blade baffle, resonant-frequency shift and damping factors of the chamber were analyzed and compared quantitatively with those of the unbaffled combustion chamber. From a view of acoustic characteristics, radial baffles with several configurations have not much difference in resonant-frequency shift and damping factor ratio with each other. On the other hand, hub and blade baffle is very effective to suppress the first tangential mode which was found to be the most harmful acoustic mode in KSR(Korean Sounding Rocket)-III engine. But more study on design parameters such as hub size and axial length should be done for complete optimization of hub and blade baffle. The present study based on linear acoustic analysis is expected to be a useful confirming tool to predict acoustic field and design a passive control devices such as baffle and acoustic cavity.