• 한국추진공학회지
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• 제15권6호
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• pp.70-77
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• 2011

우주발사체의 액체추진공급시스템에 사용되는 벤트/릴리프 밸브는 안전 밸브의 조합체로 극저온의 산화제를 주입할 때와 보관할 때 기화된 산소기체를 배출시킨다. 또한 비행 중에 추진제 탱크의 얼리지 압력을 안정적으로 유지하는 역할을 한다. 밸브의 동특성 및 유공압 작동특성을 알아보기 위해서 벤트/릴리프 밸브의 설계검증을 위해 AMESim을 이용해서 벤트/릴리프 밸브의 시뮬레이션 모델을 구성하였다. AMESim 밸브 모델을 검증하기 위해 밸브의 개폐 압력, 개폐작동시간을 수학적 계산 결과와 비교하였다. 또한 FLUENT 상용코드를 이용하여 내부유동 해석 결과를 반영하여 모델의 정확도를 높였다. 밸브 모델을 이용하여 설계인자에 대한 검증 및 작동성능을 분석하였다. 이 연구는 한국형 발사체에 사용되는 벤트/릴리프 밸브의 다양한 작동 요구조건에 대한 개발 효율성을 높일 수 있는 참고 가이드로 적용될 것으로 판단된다.

• 한국유체기계학회 논문집
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• 제12권1호
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• pp.16-21
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• 2009

In the last five years, 91 accidents from portable gas ranges and non-refillable metallic gas cartridges have occurred. The gas cylinder installed with a relief valve was developed to prevent an explosive accident from the gas cartridge. In this study it was carried out to evaluate the safety of a gas cylinder mounted with a relief valve which can prevent an explosion. Under the real using condition and the extreme condition the gas cylinder is heated with an electric heater. Simultaneously, the operating pressure is checked and the suitability of releasing flux is evaluated. And the possibility of fire or explosion was tested when the gas was released from the relief valve at the real using condition. Using a numerical simulation method, the diffusion of butane gas released from a relief valve was visualized.

• 한국유체기계학회 논문집
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• 제16권5호
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• pp.29-35
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• 2013

Butterfly valve seated rubber has been widely used in water works and industrial fields because it has advantages which are small installation area and low weight. The size and material of butterfly valve have been selected by service environments and purposes. But there are out of the ordinary to find papers for the life characteristics of the butterfly valve. So, this study carries out the accelerated life test, which has an acceleration factor with pressure, using performance and life test equipment. Accelerated model is adopted with 3 stress level and the inverse power law model to estimate the life of the test samples. After the analysis of the test result, accelerated index has 7.0 and the acceleration factor has 208 which is applied with field condition with the pressure 6.3 bar.

• 한국안전학회지
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• 제25권6호
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• pp.22-27
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• 2010

Flow Coefficients of intake port in an engine cylinder head were measured by a newly designed flow rig. In measuring the flow coefficient with traditional method, the valve lift was manually varied by technician with adjusting a micrometer which is directly connected to the intake valve of the cylinder head. The cam shaft of the cylinder head is directly rotated by a step motor and the valve lift was automatically varied with cam shaft profile in the newly designed flow rig. The measurement of the flow coefficient was automated by rotating the cam shaft with the step motor. Automatic measurement of the flow coefficient could be safely measured by separating a technician from the noise and vibration of the traditional flow rig. Also, the automatic measurement of the flow coefficient reduce the measurement time and provide meaningful statistical data.

• 한국기계가공학회지
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• 제12권2호
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• pp.81-90
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• 2013

A study on the flow-structure characteristics of marine 3/2WAY pneumatic valve is essential for optimizing the performance of ship engines. It is important that the valve has desirable safety factor and reduced weight from safety and economic point of view. In this paper, flow-structure characteristics of pneumatic valve is obtained by being optimized based on the proper design criteria. The air with the pressure of 30 bar is the working fluid which is made to fill in the tack in short time. This time is defined as the filling time. On optimum design by considering the flow-structure characteristics, the approach is based on (1) the mathematical formulation of design decisions using the compromise decision-making method, and (2) the approximation technique of response surfaces. The methodology is demonstrated as the multi-objective optimization tool to improve the performance of marine 3/2WAY pneumatic valve.

• 한국유체기계학회 논문집
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• 제8권3호
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• pp.16-25
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• 2005

The purpose of this study is localization of safety relief valves for Nuclear Service. The safety relief valve is the important equipment used to protect the pressure vessel, the steam generator and the other pressure facility from overpressure by discharging the operating medium when the pressure of system is reaching the design pressure of the system. We developed design technology used FEM ' CFM about safety relief valve for Nuclear Service according to ASME (or KEPIC) Code and KHNP's Technical Specification. To prove validity of a design technology, actually, we manufactured and inspected and tested the sample products designed according to a developed technology. The capacity qualification test was achieved according to requirement of ASME(or KEPIC) Code by NBBI and the functional qualification test was achieved according to ASME QME-1 for operating condition in technical specification of KHNP by NLI. Therefore we have to achieve the development of safety relief valves for Nuclear Service with our own technologies.

• 한국가스학회지
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• 제18권6호
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• pp.27-31
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• 2014

본 연구에서는 LP가스 용기용 밸브에서 취약할 것으로 예상되는 Part 1, Part 2, Part 3 지역에 대한 강도안전성을 FEM으로 해석하였다. 밸브의 두께가 1.5mm이고, LPG 압력이 3.5MPa일 때 밸브의 Part 1 모서리 부분에서 27.5MPa의 Von Mises 최대응력이 걸리는 것으로 나타났다. 또한, 밸브의 두께가 1.5mm이고, LPG 압력 3.5MPa이 밸브에 작용할 때 Von Mises 최대응력은 Part 2에서 41.5MPa, 그리고 Part 3에서 46.5MPa으로 나타났다. 이러한 FEM 해석결과는 밸브의 Part 1, Part 2, Part 3에 작용하는 Von Mises 최대응력 모두가 황동소재 C3604의 항복강도 대비 9.2~15.5% 수준으로 대단히 낮은 값을 나타내고 있다. 이것은 기존의 LP가스 용기용 밸브의 두께가 지나치게 과도한 설계를 하였다는 것을 의미한다. 따라서, 밸브의 Part 1과 Part 2 지역의 두께는 황동밸브의 경량화 차원에서 얇게 설계하는 것이 바람직하다. 반면에 Part 3 지역의 두께는 기존의 밸브 두께처럼 두껍게 설계하여 높은 체결토크에도 안전한 강도를 유지하는 것이 좋다.

• 한국기계가공학회지
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• 제15권4호
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• pp.16-22
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• 2016

This study is a structural analysis of 3" Cryogenic Safety Breakaway Coupling using a manufactured product from KLAW Company. Breakaway coupling is very important in the pipe system, especially when transporting fuel or gas in the pipeline. For the analysis of the patent infringement target, Dover and KLAW Company's technologies (US 08127785, EP 0764809) were analyzed. Finally, the flip-flap valve overlap was measured after combining the breakaway coupling through 3D modeling, and the valve overlap had a 0.7mm measurement value from the height gauge. The safety breakaway coupling consisted of a total of 62 pieces (body: 42, valve module: 21).

• 해양환경안전학회지
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• 제21권3호
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• pp.309-314
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• 2015

A sunken ship often involves an oil spill. This paper was carried out to minimize environmental and cost damages stemming from oil spil of sunken shipl. Through the analysis of both the standards of the oil tank system and installation, we have identified potential oil spill sites and proposed a remedy of prevention. The result of study, the air pipes of the oil tank are a vulnerable point for oil spill. Also, the remote control devices of emergency shut-off valve have poor accessibility at abandon ship, making it difficult to shut off the emergency shut-off valve. Thus, we propose the addition of a remote quick closing valve in the air pipe and the building of a central control system.

• Journal of Advanced Marine Engineering and Technology
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• 제33권5호
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• pp.696-704
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• 2009

In this paper, the flow characteristics through an industrial safety relief valve used to protect the crankcase room in a large-sized marine engine have been numerically investigated using the moving-mesh strategy. With the room pressure higher than the cracking one, the spring-loaded disc becomes open and then the air in the room blows off into the atmosphere, resulting in the reduction of the room pressure and then the shutoff of the disc. Numerical simulations are performed on the compressible air flow through the relief valve (${\phi}160mm$) with the initial room pressure (0.11 bar or 0.12bar) higher than the cracking one (0.1 bar). The numerical method has been validated by comparing the results with the empirical ones. Results show that the disc motion and flow characteristics can be successfully simulated using the moving-mesh strategy and depend strongly on the spring stiffness and the flow passage shape. With increasing spring stiffness, the maximum disc displacement decreases and thus the total disc-opening time also decreases. In addition, the flow passage shape makes a significant effect on the velocity and direction of the flow.