• 한국분무공학회지
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• 제3권4호
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• pp.58-64
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• 1998

In the gasoline engine of fuel injection type, atomization of fuel droplet and its distribution has directly influenced the performance of engine and harmful emission. To investigate atomization characteristics of fuel spray, in this paper fuel spray of air-assisted injector is observed at the various initial conditions of ambient air temperature and air assisted pressure. Behavior of fuel spray is photographed with microscopic visualization system. The SMD of fuel droplet is measured with PMAS (Particle Motion Analysis System). The effect of air-assisted pressure and temperature of ambient air resulted in the decrement of SMD and its variation. Finally, It was found that It was found that from spray angle at the two-hole injector had measured $20{\pm}4$ degree the result of photographs by shadow graphy. The mean diameter of suns decreased and the of droplets increased with increasing the temperature in the spray fields by the results of PMAS measurement. It was found that the characteristics of sprays became finer by increasing the temperature of spray fields about 373K without the delivery of air-assistance.

• 한국자동차공학회논문집
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• 제22권3호
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• pp.228-233
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• 2014

Reduction of the atmospheric pressure in high altitude affects brake booster system which was operated by the difference between the intake pressure and the atmospheric pressure. So, braking system can not stably perform due to decrease of brake boost pressure. In this study, effects of altitude change on engine intake pressure was analyzed by prediction model of engine intake pressure which was studied previously. And engine intake pressure was simulated by simulation model in various driving conditions and environmental conditions.

• 한국해양공학회지
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• 제26권6호
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• pp.66-73
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• 2012

A pressure compensated chamber of a pilot mining robot isolates and protects an electrical-electronic system from the ambient highly pressured water. Since the inner pressure of the chamber is compensated with outer water pressure using hydraulic oil and pressure compensator, there exists a pressure difference, less than 1 bar, between outer and inner surface. The structural safety of the chamber is obtained relatively easier than the canister type which inner pressure is kept as the atmospheric pressure. However, due to the adoption of box shape for space efficiency and usage of the transparent engineering plastic viewport for checking inner circumstance, the viewport can be largely deformed. This large deformation can cause an additional tensile force, called the prying force, to the bolt-flange connection parts of the viewport. In this paper, we suggest the structural design equation considering the prying action for designing the structure of a box-shape pressure compensated chamber.

• 한국표면공학회지
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• 제45권5호
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• pp.206-211
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• 2012

Process analysis was carried out during deposition of MgO by inductively coupled plasma assisted reactive magnetron sputtering in Ar and $O_2$ ambient. At the initiation of Mg sputtering with bipolar pulsed dc power in Ar ambient, total pressure showed sharp increase and then slow fall. To analyse partial pressure change, QMS was used in downstream region, where the total pressure was maintained as low as $10^{-5}$ Torr during plasma processing, good for ion source and quadrupole operation. At base pressure, the major impurity was $H_2O$ and the second major impurity was $CO/N_2$ about 10%. During sputtering of Mg in Ar, $H_2$ soared up to 10.7% of Ar and remained as the major impurity during all the later process time. When $O_2$ was mixed with Ar, the partial pressure of Ar decreased in proportion to $O_2$ flow rate and that of $H_2$ dropped down to 2%. It was understood as Mg target surface was oxidized to stop $H_2$ emission by Ar ion sputtering. With ICP turned on, the major impurity $H_2$ was converted into $H_2O$ consuming $O_2$ and C was also oxidized to evolve CO and $CO_2$.

• 대한기계학회논문집B
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• 제36권12호
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• pp.1151-1159
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• 2012

본 논문에서는 노즐홀 직경을 확대하여 유량을 증가시킨 DME 인젝터의 가시화 실험과 분무 해석을 수행하였다. 해석의 신뢰성을 확보하기 위하여 가시화 실험과 분무해석을 비교하였고, 실엔진 모사 조건에서 분무 해석을 수행하여 DME의 거동을 예측하였다. 분사 압력과 분위기 압력이 각각 35MPa 및 5MPa인 경우 가시화 실험과 분무 해석의 도달거리는 3.57%의 차이를 나타내었다. 실엔진 모사 해석의 경우, 완전하게 발달된 DME의 분무 도달거리는 분위기 온도와 압력의 비가 300K/MPa에서 42mm로 최대를 나타내었고, 300K/MPa미만의 영역에서 DME의 분무는 분위기 압력, 300K/MPa초과의 영역에서는 분위기 온도의 영향이 지배적임을 확인하였다.

• 설비공학논문집
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• 제21권8호
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• pp.448-455
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• 2009

A performance analysis of the regenerative gas turbine system with afterfogging is carried out. Because of the high temperature at the outlet of air compressor, afterfogging has a potential of improved recuperation of exhaust heat than inlet fogging. Thermodynamic analysis model of the gas turbine system is developed by using an ideal gas assumption. Using the model, the effects of pressure ratio, water injection ratio, and ambient temperature are investigated parametrically on thermal efficiency and specific power of the cycle. The dependency of pressure ratio giving peak thermal efficiency is also investigated. The results of numerical computation for the typical cases show that the regenerative gas turbine system with afterfogging can make a notable enhancement of thermal efficiency and specific power. In addition, the peak thermal efficiency is shown to decrease almost linearly with ambient temperature.

• 한국유체기계학회 논문집
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• 제19권2호
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• pp.27-35
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• 2016

The purpose of this study is to develop a method to predict the performance and economics of a micro gas turbine cogeneration system using performance correction curves. The variables of correction curves are ambient temperature, ambient pressure, relative humidity and load fraction. All of the values of correction factors were expressed as relative values with respect to design values at the ISO conditions. Once the correction curves are obtained, system performance can be predicted relatively easily compared to a detailed performance analysis method through a simple multiplication of the correction factors of various variables at any operating conditions. The predicted results using the correction curve method were compared with those by the detailed and more complex performance analysis in a wide operating range, and its feasibility was confirmed. To illustrate the usability of the correction curve method, the results of an economic analysis of a cogeneration system considering varying operating ambient condition and load was presented.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.3230-3235
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• 2007

Design performances of various configurations of the PEMFC/GT hybrid systems have been evaluated. Based on PEMFC adopting steam reforming, various system configurations (one ambient pressure configuration and three different pressurized configurations) were designed and their performances were compared. Their Performances are also compared with the reference PEMFC system. Influences of turbine inlet temperature, pressure ratio on the hybrid systems performance were investigated and design ranges exhibits better efficiency than the PEMFC system were presented. One of the pressurized system may have much higher efficiency than the PEMFC system, while other systems hardly provide efficiency upgrade.

• 산업경영시스템학회지
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• 제30권1호
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• pp.96-104
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• 2007

Glass melting process is influenced by both control and observation factors, where control factors include quantity and mixing ratio of raw material, the amount of fuel and air in-take. Further observation factors include temperature and pressure at each step of process inside glass melting furnace. Ambient Control is an effective means to eliminate complications from excessive variation among raw materials, or external disturbance from wide fluctuation of environment around equipments. Ambient Control uses both control and observation factors mentioned above. This study suggests an effective Proactive Control System that can enable genuine 4M standardization in glass melting furnace by applying Ambient Control.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 춘계학술대회 논문집
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• pp.65-69
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• 2009

Generally Lighting system consists of lamp and luminaire. When a fluorescent lamp is installed in luminaire, power and light output is changed by ambient temperature. Particularly electrodeless lamp depends on the changes that are mercury pressure with amalgam temperature and magnetic properties with ferrite temperature. It has finally influence on optical efficiency. In this study, the temperature change of ferrite and cold spot, vessel are measured at transitional state and then same characteristics are measured with increase of ambient temperature. At transitional state, luminous flux is related to temperature change of cold spot that compare with behavior of mercury pressure and light output. At increase of ambient temperature, we analyzed change that efficiency and electrical, optical characteristics of electrodeless lamp are related to ferrite core and cold spot temperature.