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  • Title/Summary/Keyword: CFX

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Design Sensitivity Estimation of Injector Nozzle Hole Considering Cavitation (캐비테이션에 관한 인젝터 노즐 홀의 설계민감도 평가)

  • Yeom, Jeong Kuk;Ha, Hyeong Soo
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.37 no.11
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    • pp.1361-1369
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    • 2013
  • This study performs a computational fluid dynamics (CFD) analysis of the inner flow of a multihole injector nozzle by using ANSYS CFX 13.0. Based on the obtained results, a design of experiment (DOE) was performed and applied to investigate the effects of injector nozzle design parameters on cavitation. To analyze the design sensitivity and signal-to-noise ratio (S/N ratio), the hole diameter, hole length, hole angle, and K-factor of the nozzle hole were selected as design parameters, and the effect of these parameters was investigated at 16 experimental points. Consequently, it was found that the effect of the K-factor on the cavitation and inner flow of the injector nozzle is the greatest. Thus, the selection of a suitable K-factor is important in nozzle design considering cavitation flow.

Optimization of a Low Specific Speed Turbopump Impeller (낮은 비속도를 갖는 터보펌프의 임펠러형상 최적화에 관한 연구)

  • 조종현;조수용;조봉수
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.34 no.9
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    • pp.1-10
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    • 2006
  • An optimization study on a small turbopump impeller operating at the low specific speed is conducted to obtain high output head at the impeller exit. Its specific speed in SI unit (RPM, m3/sec, m) is 4.0, and the outer diameter is 56mm. On the optimization, the outer diameter of the impeller is maintained constant to restrict the pump size, and an objective function of pressure head is maximized with eight design variables, which are related with designing an impeller shape. The response surface method is used to the optimization scheme, and the commercial code CFX-10 is applied for numerical analysis. The pressure head of the objective function obtained with an optimized impeller is increased by 9.7% compared with that obtained on an impeller designed with typically recommended design parameters. This increment is caused by reducing the recirculation region within the impeller passage.

Shape Optimization of High Power Centrifugal Compressor Using Multi-Objective Optimal Method (다목적 최적화 기법을 이용한 고출력 원심압축기 형상 최적설계)

  • Kang, Hyun Su;Lee, Jeong Min;Kim, Youn Jea
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.39 no.5
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    • pp.435-441
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    • 2015
  • In this study, a method for optimal design of impeller and diffuser blades in the centrifugal compressor using response surface method (RSM) and multi-objective genetic algorithm (MOGA) was evaluated. A numerical simulation was conducted using ANSYS CFX with various values of impeller and diffuser parameters, which consist of leading edge (LE) angle, trailing edge (TE) angle, and blade thickness. Each of the parameters was divided into three levels. A total of 45 design points were planned using central composite design (CCD), which is one of the design of experiment (DOE) techniques. Response surfaces that were generated on the basis of the results of DOE were used to determine the optimal shape of impeller and diffuser blade. The entire process of optimization was conducted using ANSYS Design Xplorer (DX). Through the optimization, isentropic efficiency and pressure recovery coefficient, which are the main performance parameters of the centrifugal compressor, were increased by 0.3 and 5, respectively.

The Evaluation of Strength for the Corner Block Structure in the LNG Tank using Sloshing Pressure of the Scaled Tank (모형수조 슬로싱 하중을 이용한 LNG 탱크 코너블럭(Corner Block) 구조물의 구조강도 평가)

  • Park, Jun Hyeong;Park, Si Jong;Kim, Seong Hoon;Choi, Jae Min;Jun, In Ki
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.26 no.5
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    • pp.327-333
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    • 2013
  • The purpose of this study is to predict sloshing pressure of a actual tank by using measured pressure in scaled down tank and to evaluate with structural strength of LNG Corner Block. For this purpose, we performed sloshing analysis about 138K class tank by using Ansys CFX program, and were measured both average pressure and maximum peak pressure according to scaled tank ratio. Also, measured pressure was converted to pressure of the actual tank by Froude scale law, and we conducted the evaluation of structural strength about the conner block of actual size KC-1.

Heat Flow Characteristics on Type of Heat Transfer Plate for White Smoke Reduction under Uniform Flow Condition (균일유동에서 백연저감용 전열판 형태에 대한 열유동 특성)

  • Son, Jun;Cha, Jae Min;Wang, Zhen Huan;Kwon, Young Chul
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.1
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    • pp.591-596
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    • 2016
  • Numerical analyses were performed on the heat flow characteristics of a heat transfer plate with six different shapes (basic, rectangle, triangle, wave type) to reduce the level of white smoke at a stack. In this study, to examine the heat transfer performance (heat transfer capacity, pressure drop, turbulence kinetic energy, heat transfer coefficient) on the heat transfer plates, simulations were conducted using the commercial computational fluid dynamics software, ANSYS CFX Ver.14 under uniform flow conditions. The thermal flow phenomenon in a channel with six heat transfer plates could be predicted adequately under uniform flow conditions. The heat transfer capacity, pressure drop, turbulence kinetic energy, and heat transfer coefficient were affected by the flow rate, aspect ratio and plate shape. These results provide guidelines to design an effective heat exchanger with the wave type to reduce white smoke.

Flow Analysis for Optimal Design of Small Gear Pump (소형 기어펌프 최적화 설계를 위한 유동해석)

  • Lee, Suk-Young;Kim, Seung-Chul
    • Journal of Energy Engineering
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    • v.24 no.1
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    • pp.88-96
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    • 2015
  • Gear pump has a simple structure high reliability, easy operation and maintenance, widely used as a source of hydraulic system of hydraulic. In general, the gear pump was designed using variety of variables, the variables through the analysis of the mass flow rate and efficiency. In this paper, three-dimensional flow of the gear pump, in order to produce the optimal design of product, analysis was performed by using commercial software ANSYS v15.0 CFX. And then, combination of design parameters selected by ANSYS was carried out to confirm the simulation result. The efficiency and mass flow rate of the gear pump were studied by varying its rotational speed and the clearance between the gear tip and the housing. In the simulation results, as the rotational speed were increased, the average mass flow rate and efficiency increased. Furthermore, as the clearance between the gear tip and the housing was increased, the average mass flow rate and efficiency decreased.

Three Dimensional Electro-Fluid-Structural Interaction Simulation for Pumping Performance Evaluation of a Valveless Micropump (무밸브 마이크로 펌프의 성능평가를 위한 3차원 전기-유체-구조 상호작용 해석)

  • Pham, My;Phan, Van Phuoc;Han, Cheol-Heui;Goo, Nam-Seo
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.37 no.8
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    • pp.744-750
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    • 2009
  • In this study, the pumping performance of a piezoelectric valveless micropump is simulated. The micropump, which was developed in the previous work, is composed of a four-layer lightweight piezocomposite actuator, a polydimethylsiloxane (PDMS) pump chamber, and two diffusers. The piezoelectric domain, the fluid domain and the structural domain are coupled in the three-dimensional simulation. We used ANSYS for the piezoelectric and structural domains and ANSYS CFX for the fluid domain. The effects of driven frequency on the flow rate have been investigated by simulating the flow characteristics for 10 Hz and 40 Hz driven frequencies. The flow rates with respect to driven frequencies up to 300 Hz have been calculated.

Numerical Study on the Heat Transfer Characteristics of 360 Wh Li-ion Battery Pack for Personal Mobility (360 Wh급 퍼스널 모빌리티용 리튬이온 배터리 팩의 열전달 특성에 관한 연구)

  • Kim, Dae-Wan;Seo, Jae-Hyeong;Kim, Hak-Min;Lee, Moo-Yeon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.8
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    • pp.1-7
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    • 2017
  • This study numerically evaluates the heat transfer characteristics of a 360-Wh Li-ion battery pack. The analysis was done in ANSYS CFX using different cell arrangements, cell holders, and case materials for a personal mobility device program. A total of four cases of cell arrangements were considered, along with various materials for both the cell holder and the case, such as polypropylene, aluminum, and magnesium alloy. Out of the four cell arrangements, model 2 showed the best heat transfer performance, while aluminum showed the best heat transfer performance for the cell holder and case.

A Fluid Analysis of a Container Crane using the Computation Fluid Dynamics (전산유동해석을 이용한 컨테이너 크레인의 유동 분석)

  • Kwon Soon-Kyu;Lee Seong-Wook;Han Dong-Seop;Han Geun-Jo
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2006.06b
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    • pp.349-354
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    • 2006
  • This study analyzed the fluid state around a container crone according to a wind direction when a wind load was applied to a container crone. The container crane for this research is a model of a 50-ton class used broadly in the current ports. The dimension of an external fluid field set up diameter, 300m, height, 200m. This study considered the change of a wind velocity according to an altitude in a criterion of a wind velocity, 50m/s, applying a power series law. An incident angle applied to an interval of 30 degrees in 0180 and this study carried out a computation fluid dynamics using a CFX-10. In this study, we indicate the wind pressure according to the height and section figure of each member. In addition, we suggest the wind pressure accordint to a wind direction. And we will analyze the structure stability of a container crone from the fluid-ductile analysis in the next study.

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Numerical Study of Breakup Process of Diesel Spray (디젤분무의 분열과정에 대한 수치해석 연구)

  • Yeom, Jeong Kuk;Jung, Woo Sung
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.37 no.12
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    • pp.1489-1495
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    • 2013
  • High-pressure flows are ubiquitous in many industrial fields. A representative application is fuel injection using a common-rail control system in diesel engines, where the injection pressure in the injector exceeds 1000 bar. In high-speed injection, the fluid injected through the nozzle undergoes breakup owing to the interaction with the ambient gas. The breakup process influences mixture formation, which in turn influences combustion in diesel engines. Therefore, it is very important to analyze the breakup process of fuel spray. The Reitz and Diwakar model and cascade atomization and breakup (CAB) model were used in this study as sub-models for the numerical analysis of the breakup process of fuel spray. This study aims to precisely analyze the breakup process of spray and to investigate the breakup frequency of the injected fuel. Consequently, it proposes a suitable sub-model for analyzing the breakup process of a diesel spray by using CFX, a commercial CFD program.