• Title, Summary, Keyword: Ultra High Pressure

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A Developement of Ultra High Pressure Injection Equipment for Study on Diesel Spray Characteristics with Ultra High Pressure (극초고압 디젤분무특성 해석을 위한 극초고압 단발분사장치의 개발)

  • 정대용;이종태
    • Transactions of the Korean Society of Automotive Engineers
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    • v.11 no.5
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    • pp.50-59
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    • 2003
  • It was known that high pressure injection is an effective method to enhance thermal efficiency and decrease exhaust emissions in diesel engines. If injection pressure becomes ultra high, it is predicted that there may be a suitable injection pressure which the enhancement rate of spray characteristics is moderate. Also, there may be a limit injection pressure which spray characteristics is reversed and get worse. But these are unknown. To investigate a suitable injection pressure and a limit injection pressure, ultra high pressure injection equipment(UHPIE), which can realize the injection pressure of 3,200bar, was developed. UHPIE is a basic apparatus of single shot injection, and ultra high pressure was achieved by second stage rapid compression in short time. From the evaluation of UHPIE, a injection curve like a conventional diesel engine(jerk type) was realized. Also, it was proved that repetition of experiment was excellent. Therefore it was found that there was no problem to perform the study on the ultra high pressure injection with UHPIE. Consequently, the foundation of the study on ultra high pressure injection could be established.

A Study of Safety Acquirement for an Assessment of Ultra High Pressure System (초고압 시스템의 안전성 확보에 대한 연구)

  • Lee, Gi-Chun;Kim, Hyoung-Eui;Kim, Jae-Hoon
    • Journal of the Korean Society of Safety
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    • v.25 no.5
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    • pp.7-14
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    • 2010
  • Ultra high pressure system, which can be generally increased over 1,000bar, needs to have sealing mechanism to protect leakage and selection of the materials used in the intensifier. Components such as pressure vessel, hydraulic hose assembly, accumulator, hydraulic cylinder, hydraulic valve, pipe, etc., are tested under the impulse-pressure conditions. Components need to be tested under 1.5 to 3 times of rated pressure to check the tolerance even though rated pressure range of these components are not ultra high pressure. So, the ultra high pressure system needs to be equiped to test components. In this study, safety assessments of ultra high pressure system which are using failure analysis of components, changing the types of the control system, and finite element analysis with static condition, are investigated.

A Study on Spray Characteristics Analysis of Free Spray of Diesel Fuel with Ultra High Pressure (극초고압영역에서의 디젤연료의 자유분무특성에 관한 연구)

  • Jeong, D.Y.;Lee, J.T.;Hong, G.B.
    • Journal of ILASS-Korea
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    • v.7 no.4
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    • pp.16-22
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    • 2002
  • The characteristics of free spray with ultra injection pressure was analyzed to clear the limit pressure of diesel engine. To obtain final goal, ultra high pressure injection equipment was developed, spray patterns were visualized under various ultra injection pressures. Spray penetration and spray width, volume and entrained air mass were increased with the increase of injection pressure. Sauter mean diameter and injection durstion wert decreased. But over 3,000bar of ultra injection pressure region the rates of increase show almost similar and finally the reversed tendencies at 4,140bar.

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Effect of Ultra-high Injection Pressure on Combustion and Emission Characteristics in a Single-cylinder Diesel Engine (초고압 분사 압력 적용에 따른 단기통 디젤 엔진에서의 연소 및 배기 특성에 관한 연구)

  • Cho, Wonkyu;Kang, Seungwoo;Bae, Choongsik;Kim, Youngho
    • 한국연소학회:학술대회논문집
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    • pp.41-44
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    • 2015
  • Experimental study was conducted to investigate the effect of ultra-high injection pressure on combustion and emission characteristics in a single-cylinder diesel engine. Electronically controlled ultra-high pressure fuel injection system consistently supplied the fuel of ultra-high pressure up to 250 MPa. Various injection pressures, 40 to 250 MPa, were applied and compared. A injector with eight identical nozzle holes which have diameter of $105{\mu}m$ was used. The results showed high potential to improve the nitrogen oxide (NOx) and particulate matter (PM) trade-off relationship with an ultra-high injection pressure and the exhaust gas recirculation (EGR).

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Enhancement of Anticancer Activities from Lithospermum erythrorhizon Extracts by Ultra High Pressure Process (초고압 가공 공정을 통한 지치 추출물의 항암 활성 증진)

  • Seo, Yong-Chang;Choi, Woon-Yong;Kim, Ji-Seon;Cho, Jeong-Sub;Kim, Young-Ock;Kim, Jin-Chul;Lee, Hyeon-Yong
    • Korean Journal of Medicinal Crop Science
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    • v.19 no.2
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    • pp.103-110
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    • 2011
  • This study was performed to enhance anticancer activities of Lithospermum erythrorhizon by eluting high amount of shikonin through ultra high pressure process. Extraction yield was increased up to 5~10% by ultra high pressure process, compare to the normal extraction processes such as water solvent extraction, 70% ethyl alcohol solvent extraction. The cytotoxicity of the extracts ($1.0{\mu}g/m{\ell}$) from ultra high pressure process was showed the lowest cytotoxicity 13.4% for human lung cell (HEL299). The anticancer activities showed 80~85% by adding $1.0{\mu}g/m{\ell}$ of the extracts from ultra high pressure process in several cancer cell lines such as AGS, Hep3B, MCF-7 and HeLa cells. Among them, MCF-7 cell of the endocrine system was highest inhibited than other cells. The anticancer activities of the extracts from ultra high pressure extraction process showed 10~15%, which was higher than the extracts from normal extraction processes. From HPLC analysis of the extracts, the contents of shikonin in the extracts from ultra high pressure process was 11.42% (w/w), which was 20% higher than others. This results indicate that ultra high pressure process could increase the extraction yield of shikonin and other contents, which resulted in higher anticancer activities.

A Study on Microscopic Spray Characteristics of Free Spray of Diesel with Ultra High Pressure (극초고압 디젤 자유분무의 미시적 분무특성에 관한 연구)

  • Jeong, Dae-Yong;Lee, Jong-Tai
    • Transactions of the Korean Society of Automotive Engineers
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    • v.13 no.6
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    • pp.7-12
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    • 2005
  • In order to analyze the microscopic spray characteristics of free spray in ultra high pressure region, the droplets size and velocity of free spray injected under atmosphere condition were measured by PDPA. As injection pressure became ultra high pressure, the droplets size was decreased continuously due to the increase of mutual reaction between droplets and air. But the decreasing rate became moderate. The velocity was increased until 250 MPa, and then decreased over that of injection pressure. It was seemed that the droplet size was similar in range of $280\~350\;MPa$, but increased in 414 MPa, even though injection pressure was increased. The microscopic spray characteristics of free spray got worse in 414 MPa.

A Study on the Droplet Size Distribution of Ultra High Pressure Diesel Spray on Electronic Hydraulic Fuel Injection System (전자유압식 분사계에 의한 초고압 디젤분무의 입경분포에 관한 연구)

  • Jang, S.H.;Ahn, S.K.
    • Journal of Power System Engineering
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    • v.2 no.1
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    • pp.25-30
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    • 1998
  • In order to investigate the droplet size distribution and Sauter Mean Diameter in a ultra high pressure diesel spray, fuel was injected with ultra high pressure into the environments of high pressure and room temperature by an Electronic Hydraulic Fuel Injection System. Droplet size was measured with the immersion liquid sampling technique. The immersion liquid was used a mixture of water-methycellulose solution and ethanol. The Sauter Mean Diameter decreased with increasing injection pressure, with a decrease environmental pressure (back pressure) and nozzle diameter. Increasing the injection pressure makes the fuel density distribution of the spray more homogeneous. An empirical correlation was developed among injection pressure, air density, nozzle diameter and the Sauter Mean Diameter of spray droplets.

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Influence of Droplet Drag Models on Diesel Spray Characteristics under Ultra-High Injection Pressure Conditions (극초고압 조건에서 디젤 분무 특성에 미치는 액적 항력 모델의 영향)

  • Ko, Gwon-Hyun;Lee, Seong-Hyuk;Lee, Jong-Tai;Ryou, Hong-Sun
    • Journal of ILASS-Korea
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    • v.9 no.3
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    • pp.42-49
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    • 2004
  • The present article investigates the influence of droplet drag models on predictions of diesel spray behaviors under ultra-high injection pressure conditions. To consider drop deformation and shock disturbance, this study introduces a new hybrid model in predicting drag coefficient from the literature findings. Numerical simulations are first conducted on transient behaviors of single droplet to compare the hybrid model with earlier conventional model. Moreover, using two different models, extensive numerical calculations are made for diesel sprays under ultra-high pressure sprays. It is found that the droplet drag models play an important role in determining the transient behaviors of sprays such as spray tip velocity and penetration lengths. Numerical results indicate that this new hybrid model yields the much better conformity with measurements especially under the ultra-high injection pressure conditions.

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Influence of Ultra-high Injection Pressure and Nozzle Hole Diameter on Diesel Flow and Spray Characteristics under Evaporating Condition (증발 조건에서 초고압 분사와 노즐 홀 직경이 디젤 유량 및 분무 특성에 미치는 영향에 대한 연구)

  • Cho, Wonkyu;Park, Youngsoo;Bae, Choongsik;Yu, Jun;Kim, Youngho
    • Journal of ILASS-Korea
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    • v.20 no.1
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    • pp.43-52
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    • 2015
  • Experimental study was conducted to investigate the effects of ultra-high injection pressure and nozzle hole diameter on diesel flow and spray characteristics. Electronically controlled ultra-high pressure fuel injection system was made to supply the fuel of ultra-high pressure consistently. Three injection pressures, 80, 160, and 250MPa were applied. Four type of injectors with identical eight nozzle holes were used. The four injectors have nozzle hole diameters of 115, 105, 95, and $85{\mu}m$ respectively. Injection quantity and rate were measured to investigate flow characteristics according to injection pressures and nozzle hole diameters. Mie-scattering and shadowgraph were performed to visualize liquid and vapor phases of diesel spray in a constant volume combustion chamber (CVCC). Ambient conditions of high pressure and high temperature in a diesel engine were simulated by using CVCC.

Effect of Shockwave on Diesel Spray Characteristics in Ultra High Pressure Injection (극초고압 디젤분무의 충격파가 디젤분무특성에 미치는 영향)

  • Jeong, Dae-Yong;Lee, Jong-Tai
    • Journal of ILASS-Korea
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    • v.10 no.1
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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.

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