• 월간 기계설비
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• s.22
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• pp.124-125
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• 1992

토출배관에 Three-One Check Valve로 흡입배관에 Suction Diffuser로 시공하면 유체 차단기능, 역류방지 및 유량조절 기능 등을 겸하게 되므로 설치공간의 축소, 자재비$\cdot$인건비 절감효과를 얻을 수 있다.

• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.3
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• pp.89-95
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• 2015

Performance test was conducted for an oxidizer pump and a fuel pump for a 7 ton class rocket engine, by using water. The pumps were driven by an electric motor. The hydrodynamic performance and the suction performance were measured at flow ratio of the design and off-design conditions. Head-flow curve, efficiency-flow curve, and head-cavitation number curve were obtained. It is confirmed that the pumps can satisfy the design requirements of hydrodynamic performance in terms of the head and the efficiency. The pumps also satisfied the design requirements of suction performance.

• Fire Science and Engineering
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• v.29 no.2
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• pp.84-91
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• 2015

The purpose of this study is to suggest the reasonable model of the caliber in suction nozzle, the pressure of suction nozzle, and the flow rate about foam system of line proportioner type using in the pumpcar. To test this, the experimental study was accomplished on the ground of the standards for the Performance Certification and Product Inspection of Foam Fire-extinguishing Chemical Mixing Machine. Aqueous Film Forming Foam in 3% and pipe type air foam nozzle with line proportioner FE 40 type were used. Test result showed that the pressure of suction nozzle within the limits between 0.25 MPa and 0.35 MPa was appropriate when the caliber in suction nozzle is 4 mm. Also, the pressure of suction nozzle within the limits between 0.45 MPa and 0.60 MPa was appropriate in the higher pressure than 4 mm when the caliber in suction nozzle is 5 mm.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.11a
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• pp.335-338
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• 2007

This study carried out the 2D modeling for estimating the intake loss that is a important installed loss for the precise installed performance analysis of a gas turbine engine, and the 0D performance map that represents intake pressure loss change depending on flight Mach number and air mass flow rate was generated using the 2D modeling results. In order to evaluate the generation procedure of the intake performance map, the intake map generation was applied to a commercial aircraft intake configuration.

• Nuclear Engineering and Technology
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• v.24 no.3
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• pp.311-318
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• 1992

During mid-loop operation of Nuclear Power Plant, to prevent the Decay Heat Removal System (DHRS) from failure due to air entrainment of free surface vortex in the piping system, a set of simulating experiments was performed. Through these experiments, a relation between the non-dimensionalized numbers, such as H/d, Froude number, Reynolds number, was found. It was also found that the perturbation of the system by the disturbance such as pump start, valve operation, etc., has a strong effect on the free surface vortex. Furthermore, from viewpoint of reactor safety, a modified inlet device which is reducer type is strongly recommended for the prevention of air entrainment into DHRS.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.544-549
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• 2017

This paper aims to examine the effect of rotational fluid motion about the efficiency of the gas - liquid ejector, which is a core unit in a ship equilibrium water treatment system. The ejector is a device for injecting ozone into ship equilibrium by the negative pressure generated by exchange of momentum between water and ozone. The existing ejector ejects the driving fluid with a simple form. In this paper, however, a rotation induction device is applied to the driving nozzle so that the driving fluid can be rotated and injected. To investigate the flow characteristics by the rotational movement of the driving fluid, CFD was used. The pressure and flow rate of the driving fluid, the negative pressure and suction flow rate of the suction fluid in the suction part, and the discharge pressure were predicted. On the basis of the results, the efficiency of the ejector using the rotation induction system was 22.25%, which was about 1.7% better than that of the existing ejector. Finally, to verify the feasibility of the CFD, an experiment was conducted on the ejector using the rotation induction device and the results were similar to those of the CFD.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.10a
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• pp.109-112
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• 2004

Of late, the thrust vectoring control, using fluidic co-flow and counter-flow concepts, has been received much attention since it not only improves the maneuverability of propulsive engine but also reduces an additional material load due to the trailing control wings, which in turn reduce the aerodynamic drag. However, the control effects are not understood well since the flow field involves very complicated non: physics such as shock wave/boundary layer interaction, separation and significant unsteadiness. Existing data are not enough to achieve the effectiveness and usefulness of the thrust vectoring control, and systematic work is required for the purpose of practical applications In the present study, computational study has been performed to investigate the effects of the thrust vector control using the fluidic co-and counter-flow concepts. The results obtained show that, for a given pressure ratio, the thrust deflection angle has a maximum value at a certain suction flow rate, which is at less than $5\%$ of the mass flow rate of the primary jet. With a longer collar, the same vector angle is achievable with smaller mass flow rate.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.6
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• pp.72-78
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• 2003

In the present paper, computational studies on the hydrodynamic behavior of the inducer for the rocket-engine turbopump are presented including the effect of the mass flow rate. As the mass flow rate is increased, the inducer showed better performance with weak back flows which may have deleterious effects upon the anti-cavitation ability. But the adopted inducer showed low head rise with high volume flow rates, which may be caused by the small passage area near the trailing edge. The static pressure distributions at the shroud surface are compared with experimental results showing very good agreements except near the leading edge where strong back flows are present. The overall performance of the inducer such as, efficiency, head rise is also compared with experiments. The computational results are generally in good agreements with experimental ones near the design point, but two results show discrepancy at the high flow rate.

• Journal of Power System Engineering
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• v.13 no.6
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• pp.22-28
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• 2009

열역학 제 2법칙의 관점의 열역학적 가용에너지인 엑서지 해석법을 적용하여 가솔린, 메탄올, M90 연료를 사용한 전기점화 기관의 성능해석을 수행하였다. 열역학적 사이클 해석을 위하여 사이클을 구성하는 각 과정은 열역학적 모델로 단순화하였고, 크랭크 각도에 따른 실린더의 압력과 작동유체를 구성하는 연료, 공기 및 연소생성물의 열역학적 물성 값들을 이용하여 각 과정에서의 엑서지와 손실 일을 계산하였다. 실험데이터는 단기통 전기점화기관을 가솔린, 메탄올과 M90(메탄을 90%+부탄 10%의 혼합연료)을 연료로 WOT(Wide Open Throttle), MBT(Minimum advanced spark timing for Best Torque), 2500rpm 조건으로 운전하여 측정하였다. 계산에 이용한 자료는 실험으로 측정한 크랭크 각도에 따른 연소실의 압력, 흡입공기와 연료유량, 흡입공기 온도, 냉각수 온도와 배출가스 온도 등이다. 이를 이용하여 각 과정에서의 엑서지와 손실 일을 계산하였으며 각 과정에서의 손실 일은 연소과정에서 가장 크며 팽창과정, 배출과정, 압축과정 및 흡입과정 순으로 크게 나타났다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.05a
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• pp.88-92
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• 2009

Total pressure recovery ratio in intake is crucial factor to the operational characteristics of supersonic propulsion system because it does not compress inlet air mechanically by compressor, but does compress inlet air by ram compression. As the result of that the dynamic characteristic analysis of engine was performed before the controller was designed, it could be ascertained when the AoA of flight vehicle increases, the buzz margin decreases so that the shock wave produced outside intake in the specified area according to flight operation's characteristics. Therefore the PID control algorithm was designed to be controlled buzz margin that the characteristic of shock wave could meet the requirement of performance in intake. The PID controller was designed that the buzz margin value is being positive number using the control variables; fuel flow and nozzle throat area.