• Aerospace Engineering and Technology
• /
• v.13 no.2
• /
• pp.167-176
• /
• 2014

The pyrovalves are widely used in aerospace industry for the opening and closing of flow channel due to the light-weight, high reliability and zero-leakage. In the United States, the loss of some spacecrafts using hydrazine as the propellent were proven by the blowby. Blowby is defined as the leakage of pyrovalve ignition combustion gas to the flow channel. Since then, the interference fit was applied for the sealing of piston to prevent the blowby. In this study, literature survey on pyrovalve technology is summarized mainly for AIAA papers. Common problems, improvement method, and performance comparisons of pyrovalves are also presented.

• Journal of Energy Engineering
• /
• v.11 no.3
• /
• pp.203-209
• /
• 2002

In this study the characteristics of E-EGR valve developed by Unick were analyzed and the feasibility of application to vehicles were evaluated. Smart car (3$\ell$/100 km) and engine which is small-displacement size, 0.8-liter, of diesel passenger car developed from Mercedes-Benz were used for this experiment. It was installed a 3-cylinder turbo-charged light duty diesel engine with an electronic EGR valve. After the analysis and comparison of E-EGR valve performance under test benches, the estimation of vehicle application was executed through the EGR map and CVS-75 test result measured on the chassis dynamometer.

• Proceedings of the KAIS Fall Conference
• /
• 2009.12a
• /
• pp.88-92
• /
• 2009

본 연구에서는 상수관로 보수 작업시 필연적으로 수행하던 단수 작업을 배제 하고 단수 없이 시행 가능한 관로 내시 진단 장치와 밸브류의 유지 보수 및 성능 개선을 위한 부단수 밸브 그랜드 패킹 교체장치, 부단수 밸브 스케일 제거 장치, 부단수 밸브 교체 장치를 개발함으로써 단수에 따른 시민 불편 및 경제적 손실을 저감하고 연속적인 물공급에 대한 신뢰도를 향상시킬 수 있으며, 누수 사고시 신속한 대처로 유수율 향상에 기여 할 수 있다. 또한, 관로의 내부를 직접 육안에 의해 관찰함으로써 해당 관로의 세척, 교체 등 정확한 보수 방법을 선정할 수 있으며, 정기적인 관 내부상태 확인을 통하여 노후도 평가의 직접진단 데이터로 활용 할 수 있다.

• Aerospace Engineering and Technology
• /
• v.10 no.1
• /
• pp.70-78
• /
• 2011

The Equations of inherent flow coefficient are different from compressible to incompressible flow. The paper has been conducted to measure the inherent flow coefficient of solenoid valve under various flows. Experimental results for compressible and incompressible flow were confirmed to inherent flow coefficient correctly. The value of inherent flow coefficient for the 0.5" solenoid valve is about 2. Dynamic characteristics of a solenoid valve, which plays an important role in real model, have been analysed by AMESim simulator modeling.

• Journal of the Korean Society for Precision Engineering
• /
• v.20 no.6
• /
• pp.167-177
• /
• 2003

In this study, a mathematical nonlinear dynamic model is introduced to predict the damping force of automotive shock absorber. And 11 design parameters were proposed for the sensitivity analysis of damping force. Design parameters consist of 5 piston valve design parameters, 5 body valve design parameters and 1 initial pressure of reservoir chamber air. All of these design parameters are main design parameters of shock absorber in the procedure of shock absorber design. The simulation results of this paper offer qualitative information of damping force variation according to variation of design parameters. Therefore, simulation results of this paper can be usefully use in the design procedure of shock absorber

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.12 no.2
• /
• pp.77-83
• /
• 2012

Effect of valve conductance on performance of vacuum system was simulated for optimum design of vacuum system. In this investigation, the feasibility of modeling mechanism for VacSimMulti simulator was proposed. Application specific design of vacuum system is required to meet the particular process conditions for various industrial implementations of vacuum equipments. Geometry and length, diameter of vacuum valve were modeled as simulation modeling variables for conductance effects. Series vacuum system was modeled and simulated with varied dimensions and structures of exhaust valves. Variation of valve diameter showed the more significant effects on vacuum characteristics than that of pipeline length variations. It was also observed that the aperture structure of valve had the superior vacuum characteristics among the modeled systems.

• Aerospace Engineering and Technology
• /
• v.7 no.2
• /
• pp.162-169
• /
• 2008

Dynamic characteristics of a control valve, which plays an important role in thrust control of liquid rocket engines, have been analysed by AMESim simulator modeling. A speed control method has been proposed for the control of the valve equipped with a BLDC motor and the performances of this control method have been proved in making a comparison between the predictions of simulation and experimental results. Moreover, it is shown that a control valve with a second pre-filter is enough stable to the flow disturbances. The speed control method for BLDC motor is more simpler than PI gain scheduling method for the application in complex flow system.

• Journal of Advanced Marine Engineering and Technology
• /
• v.35 no.4
• /
• pp.443-450
• /
• 2011

Fuel gas compressor system is applied to medium FPSO. In order to avoid surge, this system used the anti-surge valves. When surge occurs it may lead to system's fracture. So anti-surge valves are evaluated structural strength and structural safety. Especially, in emergency mode, valves are must be guaranteed structural safety. In this study, structural strength and structural safety of anti-surge valve was evaluated using the numerical simulation. Unigraphics NX 4.0 was used as Geometrical models, structural strength and structural safety calculation were carried out by ANSYS Workbench 12.1. The ASME Boiler & Pressure Vessel Code is refer to allowable strength and safety factor of the valves.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.39 no.7
• /
• pp.634-642
• /
• 2011

A numerical analysis of steady/unsteady flow applying cavitation model and moving mesh method was carried out in order to analyze flow and response characteristics inside the pilot valve which controls the flight actuator system. The flow of the valve was assessed according to operation temperature and time. This research has found that valve characteristics became stable at above a specific temperature and the cavitation affected valve's performance. Internal pressure and response characteristics of the valve were analyzed and flow characteristics of steady and developed unsteady flow were confirmed to be matched each other.

• Industry Promotion Research
• /
• v.2 no.1
• /
• pp.9-13
• /
• 2017

This study deals with the check valve safety valve for residential gas piping. It can be manually shut off within 1 second in case of emergency, and it is possible to touch 3kg of pressure by hand force. To develop the technology so that it can be used repeatedly. Study results after first valve operation. And 0.61 seconds on average. Therefore, it was found that there was no problem in operation even when used as a safety valve. Third, it was found that all of the results of using the blocking ball diameter of 7mm were not abnormal. In this study, it is meaningful to develop the check valve safety valve of gas piping and verify the performance by testing with existing valve.