• 한국자동차공학회논문집
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• 제13권3호
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• pp.131-137
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• 2005

Ultra high pressure injection equipment was developed to estimate and analyze the spray characteristics in ultra high pressure injection. Spray patterns were visualized by schlieren method and analyzed in ultra high pressure. Spray tip penetration, spray thickness, spray volume, and entrained air mass increased with the increase of the injection pressure. But over 2,800 bars of the injection pressure region, it was shown that the rate of improvement was not increased remarkably ,and the spray characteristics such as spray penetration, volume, and entrained air mass were reversed and got worse at 4,140 bars.

• 한국분무공학회지
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• 제10권1호
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• pp.10-16
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• 2005

To investigate the effect of shockwave on diesel spray characteristics under ultra high pressure injection, the velocity of spray tip and shock wave were investigated using the visualization of spray by schlieren method. Spray characteristics such as the spray radius, height, and droplets size were analyzed. It is found in this study that shock wave, produced by ultra high injection pressure, propagates faster than spray tip. Spray radius of right side of nozzle tip was shorter than that of left side and spray height of right side of nozzle tip was thicker than that of left side. Droplets sue was increased at 414MPa in injection pressure because of pressure gradient between inner and outer of tile spray caused by shockwave.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2017년도 춘계 학술논문 발표대회
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• pp.224-225
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• 2017

Ultra-high-strength concrete exposed to high temperature is likely to cause spalling. Spalling is caused by the vapor pressure of the concrete, and the vapor pressure may be different depending on the heating conditions of the concrete. Therefore, in this study, a ring-type restrained specimen was fabricated using ultra-high-strength concrete and the vapor pressure generated in the concrete by heating condition(rapid and slow heating) was evaluated.

• International Journal of Automotive Technology
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• 제6권2호
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• pp.125-131
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• 2005

This article reports the experimental and numerical results for free sprays under ultra-high injection pressure conditions to give us better understandings of spray characteristics and also to make clear a limit pressure condition in diesel sprays. The high pressure injection system developed in this work is devised to reach ultra-high pressure conditions in the range from 150 MPa to 355 MPa. The free spray injected from a single nozzle injector is visualized by the Schlieren technique and the high speed camera. In particular, it is found that the shock waves are present and propagated along the edge of spray in the downstream direction. The measured spray penetration length increases gradually with the injection pressure, but its increasing rate is decreased as the injection pressure increases. The Sauter mean diameter is also no longer augmented for the injection pressures higher than 300 MPa. In addition, the three­dimensional numerical simulations are conducted for comparing the measurements with the predictions based on two different breakup models. The TAB model results show better agreements with experimental data than the WAVE model under ultra-high injection pressure conductions. Moreover, the simulation results show that the gas-phase pressure increases substantially in the vicinity of the spray tip region. It supports the experimental observation that the shock waves are formed at the front of spray tip and are propagated downstream.

• 한국화재소방학회논문지
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• 제31권5호
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• pp.63-69
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• 2017

본 연구에서는 초고압 펌프의 개발과 같이 사용할 수 있는 초고압용 장거리 호스 개발에 관한 연구이며, 접근과 방수거리의 도달이 어려운 초고층 건물 및 대심도 터널의 화재진압에 효율적으로 적용이 가능함과 동시에 축광 성능을 포함하여 소방관의 화재 진압 시 퇴로 확보에도 도움이 될 수 있는 초고압용 호스의 개발에 관한 연구이다. 호스의 성능으로서 압력 3 MPa, 유량 2000 lpm을 목표로 초고압 호스를 개발하였으며, 2중의 자켓과 3중의 폴리우레탄 코팅 및 52의 경사를 사용하여 매우 촘촘하고 높은 고압에도 견딜 수 있는 초고압 소방호스를 개발하였다. 개발된 초고압 호스의 성능을 확보하기 위하여 구조 및 외관, 고압에서의 누수, 길이, 신장률, 박리시험, 마찰시험, 파단압시험 및 자유낙하 시험 등이 공인된 인증기관에서 수행되었으며 수행결과 성능에 이상이 없는 것으로 파악되었다. 또한 소방관의 화재진압 시 퇴로를 확보하기 위한 축광 성능의 초고압 호스에 추가하여 연구 및 개발하였으며, 휘도시험의 값으로 축광의 발광시험 개시부터 40분 후까지 휘도 측정치가 휘도시험의 기준 값 이상으로 충분히 확보되는 것을 확인할 수 있었다. 향후, 이와 같은 초고압용 소방용 호스가 상용화가 되어 현장에서 적용된다면 초고층 건물의 화재진압 및 장대터널에서의 화재진압에 있어서 현재 사용되고 있는 소방호스 보다 개선된 화재 진압 및 안전한 퇴로를 확보하는 측면에서 기여할 수 있을 것으로 판단된다.

• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.2122-2122
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• 2001

The ultra-high pressure technology fur the preservation of foods is under intense research to evaluate its potential as an alternative or complementary process to traditional methods of food preservation. Traditional processing methods usually need a large amount of energy, may cause unwanted reactions in the food, leading to cooked flavor and loss of vitamins, etc. The application of ultra-high hydrostatic pressure for food processing consists of subjecting the food to pressures in the range of 100-1000 ㎫. The ultra-high pressure inactivates the microorganisms and some enzymes, promotes the germination of spores and extends the shelf-life of the foods. This new technology follows the “minimal processing” concept minimizing the quality degradation, saving the vitamins, essential nutrients and flavors as well as utilizing less energy. We joined the research team at our University involved in the mentioned technology using an ultra-high pressure equipment, recording of the near infrared spectra and signal response of a chemosensor array (electronic nose) of their meat (beef and pork), vegetable and fruit samples exposed to different pressure. The results of our investigations achieved by evaluating the measured data using PCA and PQS methods will be presented.

• Journal of Advanced Marine Engineering and Technology
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• 제20권5호
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• pp.82-92
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• 1996

A computer simulation with predict the fuel injection rates and the fuel injection pressure behaviors in diesel engine fuel injection systems would by very useful in designing or improving fuel injection systems. In this paper we developed computer program in order to predict the behaviors of the fuel injection rate and the injection pressure for Electronic Hydraulic Ultra-High Pressure Fuel Injection System. We've applied the continuity and momentum equations for the hydraulic phenomena and the dynamics of individual components of the Electronic Hydraulic Fuel Injection System. To solve all the equations numerically we've applied the Runge-kutta IV method. Water hammer equations were applied for the hydraulic pipe solution, and the method of characteristics was employed in our calculations. The simulation results were compared with the experimental results for: Accumulator pressure, Injection pressure and unjection rate. As a result, The simulation results agree very well with our experimental results. We found that a large accumulator and the high speed solenoid valve were required, and the compression volume of the fuel had to be as small as possible in order to acheive ultra-high pressure fuel injection.

• 한국약용작물학회지
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• 제22권2호
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• pp.121-126
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• 2014

This study was designed to evaluate antioxidant activity of Curcuma longa L. leaves treated by ultra high pressure extraction. Curcuma longa L. leaves was subjected to 5,000 bar for 5 and 15 min at $25^{\circ}C$ The highest phenolics and flavonoids content was observed in the treatment of high pressure extraction for 15 min ($308.28{\mu}g/mg$, $124.33{\mu}g/mg$). The DPPH scavenging activity was 82.34% at $1.0mg/m{\ell}$ of Curcuma longa L. leaves treated by ultra high pressure process for 15 min. The highest SOD-like acitivity of Curcuma longa L. leaves ($1.0mg/m{\ell}$) was observed at ultra high pressure extraction for 15 min (67.54%). The high pressure extraction significantly increased the contents of phenolics and flavonoids and also enhanced the antioxidant activity. These results provide useful information for enhancing biological properties of Curcuma longa L. leaves.

• 한국자동차공학회논문집
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• 제24권3호
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• pp.338-344
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• 2016

The study is actively being performed to increase fuel injection pressure of common rail system among countermeasures to meet the emission regulation strengthen of the Diesel engine. The common rail fuel injection tube in such ultra high pressure common rail system has the weakest structural characteristics against vibration that is generated by fuel injection pressure and pulsation during engine operation and driving. Thus the extreme durability is required for common rail fuel injection tube, and the drawing process is being magnified as the most important technical fact for strength of seamless pipe that is the raw material of common rail tube. In this respect, we analyzed the characteristic of dimension and stress variation of the ultra high pressure common rail fuel injection tube by variation of Die and Plug angle in drawing process. Based on the analysis, we tried to obtain the raw material strength of common rail fuel injection tube for applying to the ultra high pressure common rail system. As a result, Plug angle is more important than entry angle of Die and we could obtain the target dimension and strength of the ultra high pressure common rail fuel injection tube through optimization of Plug angle.

• 한국분무공학회지
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• 제8권4호
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• pp.17-23
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• 2003

To find suitable injection pressure, ultra high pressure impinging spray characteristics were investigated with a impinging distance and a impinging angle by using high pressure injection system. As impinging distance was increased, spray penetration was decreased but spray height was increased. For increase of injection pressure, spray penetration and spray height were increased until 2,500bar. But over this injection pressure region, the rate of increase was decreased suddenly.