• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2005년도 제24회 춘계학술대회논문집
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• pp.405-408
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• 2005

혼합챔버 내에서 패브리-초킹(Fabri-chocking)이 발생한다는 가정을 이용하여 이차목을 갖는 환형분사 초음속 이젝터의 이론 해석을 수행하였다. 부유동 압력을 예측하기 위해 혼합챔버 입구에서 패브리-초킹면 사이를 비혼합이론(non-mixing theory)을 이용하여 계산하였다. 혼합챔버의 수축각에 의해 발생하는 깔때기 모양의 경사충격파를 이차원 경사충격파로 모사하였고, 패브리-초킹면의 주유동에만 영향을 미친다고 가정하였다. 그 결과 혼합챔버의 수축각이 4도보다 작은 조건에서 실험값을 잘 예측하는 것을 확인하였다.

• 한국추진공학회지
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• 제9권1호
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• pp.61-66
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• 2005

혼합챔버 내에서 패브리 초킹(Fabri choking)이 발생한다는 가정을 이용하여 이차목을 갖는 환형분사 초음속 이젝터의 이론 해석을 수행하였다. 부유동 압력을 예측하기 위해 혼합챔버 입구에서 패브리 초킹면 사이를 비혼합 이론(non mixing theory)을 이용하여 계산하였다. 혼합챔버의 수축각에 의해 발생하는 깔때기 모양의 경사충격파를 이차원 경사충격파로 모사하였고, 패브리 초킹면의 주유동에만 영향을 미친다고 가정하였다. 또한 패브리 초킹면의 주유동 압력과 부유동 압력이 같다는 물리적인 제한조건을 사용하였다. 그 결과 혼합챔버의 수축각이 4도보다 작은 조건에서 실험값을 잘 예측하는 것을 확인하였다.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2005년도 제31회 KOSCO SYMPOSIUM 논문집
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• pp.238-244
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• 2005

This study performs the pilot-plant experiments to evaluate the effect of the oxygen enrichment on the co-incineration of municipal solid waste and organic sludge from a wastewater treatment facility. The design capacity of the stoker-type incinerator pilot-plant is 150 kg/h. Combustion chamber temperatures were measured as well as the stack gas concentrations, i.e., NOx, CO, and the residual oxygen. The maximum ratio of organic sludge waste to the total waste input is 30%. Also the oxygen-enriched air with 23% of oxygen in supplied air is used for stable combustion. As the co-incineration ratio of the sludge increased up to 30% of the total waste input, the primary and the secondary combustion chamber temperature was decreased $to900^{\circ}C$ (primary combustion chamber), $750^{\circ}C$(secondary combustion chamber), respectively, approximately $200^{\circ}C$ below the incineration temperature of the domestic waste only (primary: $1,100^{\circ}C$, secondary: $950^{\circ}C$). However, if the supplied air was enriched to 22% oxygen content in air, the incinerator temperature was high enough to burn the waste mixture with 30% sludge, which has the heating value of 1,600 kcal/kg.

• 유공압시스템학회논문집
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• 제6권1호
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• pp.17-24
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• 2009

The performance improvement of a small-size integrated-type fully hydraulic breaker is studied in this paper. Mathematical modeling of the breaker is established and verified by experiment. Through sensitivity analysis using AMESim, the key design parameters are selected and nearly optimized to maximize the impact energy as well as to improve the dynamic characteristics such as the piston upper chamber pressure, piston and valve displacements. As a result, the impact energy, blows per minute(bpm) and output power are increased by 52.9%, 1%, and 55.6%, respectively compared with the current design. The dynamic characteristics of the piston upper chamber pressure, piston and valve displacements are also improved by the design change.

• Journal of Advanced Marine Engineering and Technology
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• 제28권7호
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• pp.1055-1062
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• 2004

As for the Production of internal combustion engines there has been further movement toward development of high Performance engines with improved fuel efficiency as well as a lightweight and a small size. These tendencies help to solve the problems in engines for example, such as thermal load. abnormal combustion and so on. In order to investigate these Problems, a thin film-type probe for measuring instantaneous temperature has been suggested. A method for manufacturing such a probe was established in this study The instantaneous surface temperature of a constant volume combustion chamber was measured by using this probe and the heat flux was obtained through Fourier analysis In order to thoroughly understand the characteristics of combustion. authors measured wall temperature of combustion chamber and calculated heat flux through a cylinder wall while varying the protrusion height of probe. For these Purposes, the instantaneous surface temperature probe was developed. thereby making possible the analysis of instantaneous temperature of wall surface and the detection of unsteady heat flux in the constant volume combustion chamber.

• 전기학회논문지
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• 제59권1호
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• pp.152-159
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• 2010

This paper describes the actual application of a feedback control loop as a means for minimizing turbine impulse chamber pressure variation during the turbine steam valve tests at a 1,000 MW nuclear power plant. The chamber pressure control loop was implemented in the new digital control system which was installed as a replacement for the old analog type control system. There has been about 40MW of the generator output change during the steam valve tests, especially the high pressure governing valve tests, because the old control system had not the impulse chamber pressure control so the operators had to compensate steam flow drop manually. The process of each valve test consists of a closing process and an reopening process and the operators can make sure that the valves are in their sound conditions by checking the valves movement. The control algorithm described in this paper contributed to keep the change in megawatt only to 6MW during the steam valve tests. Thereby, the disturbance to reactor control was reduced, and the overall plant control system's stability was greatly improved as well.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.1112-1118
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• 2007

This paper investigates the performance of an electromagnetic type active control engine mount (ACM) recently developed in the laboratory. The ACM employs the basic structure of the conventional hydraulic engine mount of which upper chamber is connected to a dual magnet electromagnetic actuator. The actuator, that essentially replaces the existing decoupler of the conventional passive hydraulic engine mount, actively controls the upper chamber pressure. Using the linearized ACM model incorporated with the actuator dynamics, we suggest an optimal design of ACM, maximizing the actuator efficiency as well as the vibration isolation efficiency.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2010년 춘계학술대회논문집
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• pp.252-257
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• 2010

The availability of the thermal energy has been deeply recognized recently to encourage the cascade usage of thermal energy from combustion. Within the frame work, a 1 kW class Stirling engine based cogeneration system has been proposed for a unit of a distributed energy system. The capacity has been designed to be adequate for the domestic usage, which requires high compactness as well as low emission and noised. To develop a highly efficient system with satisfying these requirements, a premixed slot flame burner has been proposed and a series of numerical simulation has been performed to establish a design tool for the combustion chamber. The thermal radiation model has been found to highly affect the computational results and a proper resolution to analyze the heat transfer characteristics of the high temperature heat exchanger. Finally, the combustion characteristics of the premixed flame with the metal fiber type burner has been studied.

• 한국분무공학회지
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• 제4권3호
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• pp.15-23
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• 1999

The use of LPG as clean fuel for Diesel engine is very attractive way to reduce soot and NOx emission. In this study, a numerical study has been done to know the transient behavior of LPG fuel in chamber pressures which is held at a pressure above (0.37MPa)and below(0.15MPa)the fuel vapor pressure. Results show that the vortex formed within the start of injection at the leading edge of the spray cone and was most apparent for 0.15MPa chamber pressure case. The high speed photographs and model results showed a narrower cone angle during the quasi-steady spray period at the 0.37MPa chamber pressure compared to the 0.15MPa case. And it can be shown that more realistic vaporization process is necessary to predict the spray length well.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.779-785
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• 2006

Particle transport and deposition characteristics on semiconductor wafers inside the chamber were experimentally investigated via a particle generation & deposition system and a wafer surface scanner. Especially the relation between particle size($0.083{\sim}0.495{\mu}m$) and particle deposition velocity with ESA(Electrostatic Attraction) effect was studied. Spot deposition technique with the deposition system using nozzle type outlets of the chamber was newly conducted to derive particle deposition velocity and all experiment results were compared with the previous study and were in a good agreement as well.