• Journal of Advanced Marine Engineering and Technology
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• 제28권7호
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• pp.1072-1081
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• 2004

This paper is to investigate on the effects of the hole size of spring type EFV(excessive flow valve) for automobiles The analytical and experimental methods were employed to measure the discharge coefficient. choked flowrate and Pressure wave in a bombe, line and vaporizor The size of EFV was determined to meet the legally permitted limits with the capacity of engine displacement up to 2000cc, according to the obtained discharge coefficient. The Purpose of this paper is 1) to find causes of bad acceration performance in LPG engines 2) to find optimal design determination of spring coefficient and orifice hole size of excessive flow valve in LPG engine 3) to find pressure wave of bombe, line and vaporizer through expeimental verification. Experimental results indicated that increase of orifice size 0.5mm to 1mm be caused to increase discharge coefficient, and choked flow rate and decrease operation range of difference pressure wave.

• 한국자동차공학회논문집
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• 제5권5호
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• pp.157-169
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• 1997

The effects of intake port eccentricity on the characteristics of in-cylinder swirl ratio in a 4-valve diesel engine having the two intake ports; one is a helical intake port and the other is a tangential intake port were investigated by using the ISM(impulse swirl meter) in steady flow test rig. Swirl ratio($R_s$) and mean flow coefficient($C_{f(mean)}$) with valve eccentricity ratio($N_y$) and axial distance(Z/B) were measured. As the results from this experiment, the characteristics of in-cylinder swirl ratio formed by a 4-valve cylinder head were largely affected by intake port eccentricity. There is a difference in the mass flowrate through the two intake ports, and the mass flowrate through the tangential intake port is 19% more than that of the helical intake port. Therefore, we could know that the effects of the mass flowrate ratio through each intake port besides intake port shape should be conidered.

• 한국수소및신에너지학회논문집
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• 제27권6호
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• pp.764-772
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• 2016

This paper presents on the evaluation of numerical analysis model of a ball valve used for a gas pipeline. The ball valve has important role to control the gas flow of the pipeline as well as safety operation to prevent gas explosion at the emergency. For the validation of numerical simulation, the computational domains are introduced three different types: a hexahedron chamber connected to a pipeline outlet without considering the geometry of pressure tubes, a pipeline only considered the geometry of pressure tubes, and a pipeline connected both of the a hexahedron chamber and pressure tubes. The commercial code, SC/Tetra, is introduced to solve the three-dimensional steady-state Reynolds-averaged Navier-Stokes analysis in the present study. The valve flow coefficient and valve loss coefficient with respect to the valve opening rate of 30%, 50%, and 70% are compared with experimental results. Throughout the numerical analysis for the three analysis domains, pressure computed along the pipeline is affected by computational domains. It is noted pressure obtained by the computational model considering both of the a hexahedron chamber and pressure tubes has a relatively good agreement to the experimental data.

• 한국기계가공학회지
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• 제18권3호
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• pp.103-108
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• 2019

The results of the measurement of the flow-rate coefficient (Cv-value) and the analysis of a small ball valve are summarized follows. The Cv-values of 1/2-, 3/4- and 1-inch ball valves were measured using a flow-rate measurement test. The manufacturer obtained the Cv-value using a theoretical calculation method. The new experimental measurement and analysis method yielded more reliable results. In addition, the Cv value obtained through numerical analysis was almost identical the value provided by the manufacturer, which was based on experimental results. A Study on Flow Analysis results are all similar appearances as the reliability of the results.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2005년도 연구개발 발표회 논문집
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• pp.613-616
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• 2005

In general, the hollow jet valve, the fixed cone valve had been used for the urgency released or maintenance of the flow rate. Nowadays, the butterfly valve, the gate valve are applied in economic performance and operation maintenance more than the hollow jet valve, the fixed cone valve. However, in the case of butterfly valve, it should be required the strict application standard to the cavitation coefficient because the structural axis and disk were situated in pipe channel and the occurring the shock problem by Karman Vortex. And, the judgment data for choice were slight lowdown in water supply and drainage facilities standard or Japanese penstock technology standard, various standard of KOWACO etc. Therefore. there were investigated the valve inside phenomenon (cavitation, disk chattering, vibration) by velocity of flow and the stability examination of body by high velocity of flow through flow scale model test using the numerical analysis and PIV to establish the applicable extensibility of the butterfly valve for the urgency released valve.

• 한국수소및신에너지학회논문집
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• 제35권4호
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• pp.363-369
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• 2024

Needle valves are instrumentation devices with quick-opening inherent flow characteristics, used in pipelines requiring rapid flow supply immediately upon opening the flow path. For needle valves applied in liquefied hydrogen plants operating in cryogenic environments, it is necessary from the initial design stage to have various inherent flow characteristics in addition to quick-opening, depending on the intended usage. In this study, the inherent flow characteristics of a 1/2'' liquid hydrogen needle valve were evaluated through computational fluid dynamics analysis. Disk shapes exhibiting various inherent flow characteristics were proposed by deriving the flow coefficient (Cv) according to changes in disk shapes. Among the disk shapes that directly affect the Cv, the disk length and slope angle were selected, and case studies were conducted with nine parameter combinations. From the results of the normalized Cv regarding to opening rates, disk lengths and slope angles exhibiting quick-opening, equal-percentage, and linear inherent flow characteristics were determined.

• 한국유체기계학회 논문집
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• 제10권4호
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• pp.61-70
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• 2007

Numerical analysis of three dimensional incompressible turbulent flows in LNG marine high pressure drop control valves was carried out by using the CFD-ACE from ESI-Group. In this study, flow characteristics of control valves with complex flow fields including cavitation effect were investigated. Simulation was performed on five models of control valve that had different orifice diameters of anti-trim and the size of valve. Comparing newly designed control valves for controling the occurrence of cavitation with the conventional valve, new valves showed a improved flow pattern with almost no cavitation.

• 대한기계학회논문집B
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• 제21권7호
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• pp.948-961
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• 1997

The effects of intake port eccentricity and a partition between the two intake ports on the incylinder swirl characteristics in a 4 valve diesel engine having the two intake ports, one is a helical intake port and the other is a tangential intake port, were investigated by using the impulse swirl meter(ISM) in a steady flow test rig. Mean flow coefficient ( $C_{f(mean)}$, swirl ratio ( $R_{s}$) and the mass flowrate through the two intake ports with and without intake port partition were measured. The results showed that the characteristics of in-cylinder swirl ratio formed by a 4-valve cylinder head were largely affected by valve eccentricity ratio ( $N_{y}$) and the existence of an intake port partition between the two intake ports. Mean flow coefficient ( $C_{f(mean)}$) increases and swirl ratio ( $R_{s}$) decreases in case of being the partition between the two intake ports. And also the mass flowrate through the tangential intake port is 19.0% and 7.7% more than that of the helical intake port in case of the two intake ports with and without partition respectively.ively.

• 항공우주기술
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• 제11권1호
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• pp.84-90
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• 2012

연소기용 연료개폐밸브는 파일롯 공압으로 포핏을 열고 스프링 힘에 의해 닫음으로써 로켓엔진의 연료 유량을 제어한다. 현재 개발 중인 연소기 연료개폐밸브는 액추에이터에서 압력이 제거되더라도 유로부에 해당 압력이 존재한다면 스스로 열림을 유지하는 방식으로 설계되어 있다. 밸브의 성능을 평가하기 위해 밸브가 열리고 닫히는 특성에 따라 힘 평형 상태를 분석할 필요가 있다. 이를 위하여 밸브의 포핏이 열리기 위한 파일롯 압력과 닫히기 위한 유로부 압력을 힘 평형에 의해 조절되도록 설계하였다. 또한, 상용 소프트웨어인 Fluent CFD 해석을 통해 밸브의 고유유량계수를 구해보았다. 예측과 해석을 통해 획득된 결과들은 실험 결과와 비교하였다.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 동계학술발표대회 논문집
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• pp.357-362
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• 2008

This study have goal with reverse engineering for petrochemistry of high pressure ball valve for localization. Ball valve for development accomplished with flow analysis based on provision of ANSI B16.34, ANSI B16.10, ANSI B16.25 In order to localize the petrochemistry high pressure control valve. Numerical simulation using CFD(Computational Fluid Dynamic) in order to predict a mass flow rate and a flow coefficient form flow dynamic point of view. The working fluid assumed the water($H_2O$). The valve inlet and outlet setup a pressure boundary condition. The outlet pressure was fixed by atmospheric pressure and calculated inlet velocity 5m/s. CFD solver used STAR-CCM+ which is commercial code. The result shows change of mass flow rate according to opening and closing angle of valve. Flow decrease observed open valve that equal percentage flow paten which is general inclination of ball valve. The structural analysis used ANSYS which is a commercial code. Stress analysis result of internal pressure in valve showed lower than yield strength. This is expect to need more detail design and verification for stem and seat structure.