• Title/Summary/Keyword: Fluent code

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Analysis of Flow Characteristics in a Groove of Hydraulic Spool Valve (유압 스풀밸브 그루브 내에서의 유동특성 해석)

  • Park, T.J.
    • Transactions of The Korea Fluid Power Systems Society
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    • v.4 no.4
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    • pp.15-20
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    • 2007
  • All of the hydraulic spool valves adopt radially grooved spools to avoid hydraulic locking. In this paper, a commercial computational fluid dynamics (CFD) code, FLUENT is used to investigate the accurate Poiseuille flow characteristics inside single groove. The stream lines, velocity and pressure distributions are obtained for various groove widths, depths and shapes. The stream lines are highly affected by groove shape and there occurred large vortexes inside groove beyond a certain ratio of groove width to depth. Especially the U shaped groove restrains the occurrence of vortex. Therefore the numerical method adopted in this paper can be use in optimum designing of multi-grooved hydraulic spool valves.

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Prediction of Non-Contact-Type Seal Leakage Using CFD (CFD를 사용한 터보기계 비접촉식 실의 누설량 예측)

  • Ha Tae-Woong
    • The KSFM Journal of Fluid Machinery
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    • v.9 no.3 s.36
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    • pp.14-21
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    • 2006
  • Leakage reduction through annular type seals of turbomachinery is necessary for enhancing their efficiency and the precise prediction method of seal leakage is needed. The analysis based on Bulk-flow concept has been mainly used in predicting seal leakage. However, full Navier-Stokes Equations with turbulent model derived in the seal flow passage have to be solved for improving the prediction of seal leakage. FLUENT 6 which is commercial CFD(Computational Fluid Dynamics) code based on FVM(Finite Volume Method) and SIMPLE algorism has been used to analyze leakage of various non-contact-type seals in this presentation. Comparing with the results of Bulk-flow model analysis and experiment, the result of CFD analysis shows good agreement with that of existing theoretical analysis for the incompressible grooved seal and compressive plain and staggered seal. The CFD analysis also shows improvement on the leakage prediction of the incompressible plain seal and compressive see-through-type labyrinth seal.

A Study on the Flow Characteristic of Non-Thermal Plasma Reactor for Demonstration (실증실험용 저온 플라즈마 반응기의 유동특성에 관한 연구)

  • Kim, Y.S.;Choi, S.H.;Kim, J.I.;Kim, T.H.;Yoo, J.S.;Paek, M.S.;Jang, G.H.
    • Proceedings of the KSME Conference
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    • 2000.11b
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    • pp.508-513
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    • 2000
  • HANJUNG has developed demonstration plant treating combustion flue gas such as dioxide($SO_2$) and nitrogen oxides(NOx). Before operating this system, we tested the inner airflow characteristic of demonstration plant in the front of plasma reactor field 1 and field 2. The experimental results of $25,000Nm^3/hr$ airflow are compared with the computational results using FLUENT code. It is found that the velocity distribution trends are matched the experimental results with the calculation results. To improve the eccentric airflow in the inlet hood, it is necessary to install the vertical guide vane as well as the horizontal guide vane.

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Funnel Design Guidance (Funnel 설계 권고안)

  • Jeong, Wang-Jo;Cho, Won-Ho;Kang, Dae-Youl;Kim, Seung-Hyuk
    • Special Issue of the Society of Naval Architects of Korea
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    • 2006.09a
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    • pp.59-64
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    • 2006
  • Most important factor to consider funnel performance is exhaust gas temperature and exhaust gas concentration Electric equipments on the wheelhouse top affected exhaust gas temperature. So, it is important that electric equipments keep away from high temperature. Though exhaust gas concentration is not a regulation and restraint, the exhaust 9as can cause serious problems for the on-board air quality and result in irreversible damage to the ship and people. So, we pocus on the exhaust gas concentration also. When judge whether a measured concentration is acceptable or not, criteria based on the LTEL (Long Term Exposure Limit). In this paper, we carried out the smoke simulation study. For this analysis, we used FLUENT which is commercial CFD (Computational Fluid Dynamics) code.

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Leakage Analysis and Design Modification of the Combination-Type-Staggered-Labyrinth Seal (누설량 저감을 위한 래버린스 실의 설계개선 및 해석)

  • Ha, Tae-Woong
    • Tribology and Lubricants
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    • v.23 no.2
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    • pp.43-48
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    • 2007
  • Leakage reduction through annular type labyrinth seals of steam turbine is necessary for enhancing their efficiency. In this study, modified geometry of the original combination-type-staggered-labyrinth seal has been suggested and numerical analysis for leakage prediction has been carried out for the modified-combination-type-staggered-labyrinth seal both based on bulk-flow model and using the CFD code FLUENT. The theoretical analysis based on bulk-flow model yields leakage reduction of the modified combination type staggered labyrinth seal by about 11%. Comparing with the result of Bulk-flow model analysis, the leakage result of CFD analysis shows reasonable agreement within 9.8% error.

Analysis of Performance of Turbine Exhaust Nozzle for Liquid Rocket Engine (액체로켓엔진의 터빈 배기노즐 성능 해석)

  • Cho, Won-Kook;Seol, Woo-Seok
    • 한국전산유체공학회:학술대회논문집
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    • 2008.03b
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    • pp.316-319
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    • 2008
  • A computational analysis has been conducted on the compressible flow in the turbine exhaust nozzle of the gas generator cycle liquid rocket engine. The commercial CFD code Fluent has been used. Four nozzle designs have been compared to select the turbine exhaust nozzle concept. Three candidates with single nozzle have comparable performance. The model with bifurcated nozzles shows significant performance loss. However it will be better in the view of balanced thrust distribution because of its symmetric geometry.

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A CFD Analysis of the Oil Flow in a Hydraulic Shock Absorber (유압 완층기 내에서의 오일 유동에 대한 CFD 해석)

  • Park, K.T.;Park, T.J.
    • Transactions of The Korea Fluid Power Systems Society
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    • v.5 no.1
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    • pp.20-26
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    • 2008
  • Various types of hydraulic shock absorbers are widely used in many fields because of its numerous advantages. However, in order to design adequate damping characteristics, accurate flow data near the orifices are required essentially. In this paper, a commercial computational fluid dynamics(CFD) code, FLUENT is adopted to investigate the flow characteristics near orifices of a shock absorber. Static pressure and velocity vector distributions, fluid path lines are presented for compression/tension strokes and various piston speeds. In order to validate the result of analysis, the numerically obtained damping forces are compared with those of analytical estimations obtained by modified Bernoulli equation. The results reported herein will provide better understanding of the detailed flow fields within shock absorber, and the CFD analysis method proposed in this paper can be used in the design of other types of hydraulic shock absorber.

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A Dynamic Characteristics of the Tube Flow with the Variations of the Axially-Positioned Super-Circled Orifice Shape (유동방향의 초원형 오리피스 형상 변화가 관유동에 미치는 동특성 연구)

  • Kim, Youn J.;Lee, Sang-Sub
    • Journal of Energy Engineering
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    • v.6 no.1
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    • pp.52-57
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    • 1997
  • Dynamic characteristics of compressible flow fields in super-circled constricted tube have been studied numerically. By applying MacCormack's explicit scheme, time marching method with predictor/corrector step, Euler equation is solved to find characteristics of fluid flow in a constricted tube where a two-dimensional inviscid compressible flow is assumed. The effects of tube diameter and aspect ratios on the pressure variations are discussed extensively. The results of the developed numerical schemes are compared with those of commercial FLUENT code, and show a good agreement.

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Rotordynamic Analysis of See-through-type Labyrinth Seal Using 3D CFD (3D CFD를 활용한 관통 래버린스 실의 회전체 동역학적 해석)

  • Ha, Tae Woong
    • The KSFM Journal of Fluid Machinery
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    • v.18 no.1
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    • pp.44-50
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    • 2015
  • Labyrinth seals are commonly used in various kinds of turbomachinery to reduce leakage flow. In the present 3D CFD analysis of see-through-type labyrinth air seal, the methodology of determining leakage and rotordynamic coefficients is suggested with the relative coordinate system for steady-state simulation. The leakage flow and rotordynamic forces predicted by using different solvers and turbulent models of FLUENT are compared with the results of the existing bulk-flow analysis code LABYSEAL.FOR and experiment. The present CFD result of direct stiffness(K) shows only improvement in prediction. The results of leakage and rotordynamic coefficients as well as computing time are sensitive against the used solver and turbulent model.

Prediction of Combination-Type-Staggered-Labyrinth Seal Leakage Using CFD (CFD를 사용한 복잡한 형상을 갖는 래버린스 실의 누설량 예측)

  • Ha Tae-Woong
    • Tribology and Lubricants
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    • v.22 no.2
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    • pp.66-72
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    • 2006
  • Leakage reduction through annular type labyrinth seals of steam turbine is necessary for enhancing their efficiency and the precise prediction method of seal leakage is needed. In this study, numerical analysis for leakage prediction of the combination-type-staggered-labyrinth seal has been carried out using FLUENT 6 which is commercial CFD (Computational Fluid Dynamics) code based on FVM (Finite Volume Method) and SIMPLE algorism. The present CFD results are verified with the theoretical analysis based on Bulk-flow concept which has been mainly used in predicting seal leakage. Comparing with the result of Bulk-flow model analysis, the leakage result of CFD analysis shows good agreement within 7.1% error.