• Title, Summary, Keyword: Ambient pressure

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An Effect of Pressure and Temperature on Spray Characteristic (분무특성에 미치는 압력.온도의 영향)

  • Oh, Eun-Tak;Ryu, Ho-Sung;Ahn, Byoung-Kyu;Song, Kyu-Keun;Jung, Jae-Youn
    • Proceedings of the KSME Conference
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    • pp.946-951
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    • 2001
  • This experimental study is to investigate the intermittent spray characteristics of a pintle nozzle. High speed camera used in this expreiment with 9000fps. The factor, which controls the diesel spray, is the Injection pressure, ambient pressure and ambient temperature. In this paper, experiments were conducted free spray for the ambient pressure(3, 4, 5Mpa), nozzle Injection pressure(10, 14, 18MPa) and ambient temperature(293, 473K). With the higher opening pressure, the spray tip velocity and spray penetration increases while the spray angle decreases, On the other hand, With the higher ambient pressure, the spray angle increase while the spray tip penetration and spray tip velocity decrease. also, With the higher ambient temperature, the spray penetration decrease while the spray angle decrease.

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An Investigation on a Spray Characteristics of Oxygenated Fuel with a Piezo Injector Common Rail System (피에조 인젝터 커먼레일 시스템을 이용한 함산소연료의 분무특성에 관한 연구)

  • Lee, Sejun;Yang, Jiwong;Kim, Sangill;Lim, Ocktaeck
    • Journal of ILASS-Korea
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    • v.17 no.4
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    • pp.171-177
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    • 2012
  • To understand oxygenated fuel characteristics including spray penetration length and spray angle at a real engine ambient pressure condition, DME was injected into a high pressure chamber by a piezo injector common rail system. The piezo injector common rail system was able to apply steady injection pressure, rapid response, and accurate injection quantity. Injection and ambient pressure were varied to confirm a relation with spray form. Using a direct photographing technique, development process of DME spray was captured. DME injection quantity was enlarged linearly as increasing of the injection pressure. In the high pressure chamber, when the injection pressure was enlarged the penetration length and velocity were increased due to a big momentum of fuel particle at the same ambient pressure. When ambient pressure was increased, the DME spray penetration length and velocity were decreased since the high ambient density of nitrogen was acted as a resistance. Although the ambient pressure and injection pressure were varied, each case of spray angle was almost same since the spray angle had a connection of the injector nozzle geometry.

A study on the effect of injection pressure and ambient pressure for the growth of impinging spray (충돌 분무의 성장에 미치는 분사압과 배압의 영향에 관한 연구)

  • Cha, Geon-Jong;Seo, Gyeong-Il;Kim, Deok-Jul
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.21 no.11
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    • pp.1458-1465
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    • 1997
  • This study investigated the effects of pressure on the growth of an impinging spray. We obtained the frozen images which were scattered by Nd ; YAG laser light (pulse width : 7 ns) using synchronization circuit made in the laboratory. For an impinging spray a growth of the penetration length was progressed with increase of the injection pressure but an ambient pressure restrained its growth. The effect of an ambient pressure on penetration was larger than that of an injection pressure. The pressure ratio had an effect on the penetration growth rate. The thickness growth rate depended on both the injection pressure and the ambient pressure compositively. A lower injection pressure or a higher ambient pressure was required for spatial distribution of impinging spray.

The Characteristic Change of Pressure and Differential Transmitter due to a Rapid Change of Ambient Temperature (주위 온도의 급격한 변화에 따른 압력 및 차압 전송기의 특성 변화)

  • Chung, Jong-Tae;Ha, Young-Cheol;Lee, Cheol-Gu;Her, Jae-Young
    • 유체기계공업학회:학술대회논문집
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    • pp.321-326
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    • 2004
  • The pressure and differential pressure(DP) transmitters are used for gas flow rate calculation on the orifice gas metering system. On site, the pressure and DP transmitters are installed in a shelter to diminish the affects of environmental change such as an ambient temperature. But there has been an argument about the effectiveness of the shelter and this brought up the necessity to verify the affects of ambient temperature. These experiments were performed to verify the ambient temperature effects as observing the output of transmitters when the ambient temperature were changed from $-30^{\circ}C$ to $50^{\circ}C$. The results showed that the most of transmitters were operated in the spec range of performance criteria presented by manufacturer but the rapid change of ambient temperature could cause the larger measurement error for the DP transmitter of low span than others. Therefore the pressure and DP transmitters need to be operated and controlled within the proper range of ambient temperature.

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Identification of ambient pore pressure and rigidity index from piezocone dissipation test (피에조콘 소산시험을 이용한 평형간극수압과 강성지수의 역해석)

  • 김영상
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.49-54
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    • 2002
  • This paper describes a systematic way of simultaneously identifying the ambient pore pressure and the rigidity index (=G/s$\_$u/) of soil by applying an optimization technique to the piezocone dissipation test result. An ambient pore pressure and optimal rigidity index were determined by minimizing the differences between theoretical excess pore pressures developed by Randolph & Wroth(1979) and measured excess pore pressures from piezocone using optimization technique. The effectiveness of the proposed back-analysis method was examined against the well-documented performance of piezocone dissipation tests (Tanaka & Sakagami, 1989), from the viewpoints of proper determination of selected target parameters and saving of test duration. It is shown that the proposed back-analysis method can evaluate properly the ambient pore pressure and the rigidity index by using only the early phase of the dissipation test data. Also, it is shown that with the optimized rigidity index and ambient pore pressure the proposed back-analysis method permits the horizontal coefficient of consolidation to be identified rationally.

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Ultraviolet and green emission property of ZnO thin film grown at various ambient pressure (분위기 산소압 변화에 따른 ZnO 박막의 발광특성 변화)

  • 강정석;심은섭;강홍성;김종훈;이상렬
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.355-357
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    • 2001
  • ZnO thin films were deposited on (001) sapphire substrate at various ambient gas pressure by pulsed laser deposition(PLD). Oxygen was used as ambient gas, and oxygen gas pressure was varied from 1.0${\times}$10$\^$-6/ Torr to 500 mTorr during the film deposition. As oxygen gas pressure increase in the region below critical pressure photoluminescence(PL) intensity in UV and green region increase. As oxygen gas pressure increase in the region above critical pressure photoluminescence(PL) intensity in UV and green region decrease. Each of critical ambient gas Pressures was 350 mTorr for UV emission and 200 mTorr for green emission.

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Effect of Ambient Conditions on Spray Behavior of Gasoline Injector (가솔린 분무 거동에 미치는 분위기 조건의 영향)

  • 이창식;이기형;최수천;권상일
    • Transactions of the Korean Society of Automotive Engineers
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    • v.8 no.2
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    • pp.27-32
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    • 2000
  • The main objective of this work is to investigate the effect of ambient conditions on the spray behavior and spray characteristics of high-pressure fuel injector. For this purpose, the effects of ambient pressure and temperature on the spray characteristics have been studied by applying the analysis of visualization system and phase Doppler particle analyzer. In this experiment, the visualization of spray behavior was performed under various ambient gas conditions and injection parameters such as gas temperature, ambient pressure, injection pressure of injector, and axial distance from the nozzle tip. Based on the investigation results, the spray tip penetration and spray width decrease with the increase of ambient gas pressure in the spray chamber. The effects of the spray parameters on the microscopic characteristics of gasoline spray were discussed.

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Synthesis of Silica Aerogel at Ambient Pressure and Characterization (II) (실리카 에어로겔의 상압합성 및 특성연구(II))

  • 권영근;최세영;강신규
    • Journal of the Korean Ceramic Society
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    • v.36 no.11
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    • pp.1189-1197
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    • 1999
  • Low-density silica gel monolith was synthesized at ambient pressure by surface modification with TMCS and sub-sequent heat treatment. The mechanical thermal and optical properties of gel were studied. Compressive strength and modulus of compression of 350$^{\circ}C$-heated gel with the density of 0.24g/cm3 were 250kPa and 0.2MPa respectively. The thermal conductivity of silica gels synthesized at ambient pressure exhibited 0.02 W/m$.$K for the density of 0.24g/cm3 which is similar to that of the gel via supercritical drying and their main thermal transfer mechanism is considered to be solid and radiation conduction at room temperature. Ambient-dried silica gels were transparent blue showing about 60% of transmittance in the wavelength of 1500-2100nm and typical absorption bands of existing bonds under heat treatment at 350$^{\circ}C$. Medium scale monolity(${\Phi}$=50mm) at ambient pressure could be successfully prepared through total 5-month process period.

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An Experimental studies Spray characteristic of Pintle type Nozzle on High Pressure Chamber (고온.고압용기에서의 핀틀노즐의 분무특성에 관한 실험적 연구)

  • 송규근;정재연;오은탁;류호성;안병규
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • pp.67-73
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    • 2002
  • The characteristics of fuel spray influence on the engine performances such as power, fuel economy and emissions. therefore, the measurement of fuel spray characteristics is very important for the improvement of heat engine. The factor which controls the fuel spray is injection pressure, ambient pressure, engine speed et al.. In :his study, We measured spray angle, spray penetration and spray tip velocity considering injection pressure(10,14㎫), ambient pressure(3,4,5㎫), fuel pump speed(500,700,900rpm) in the high temperature and pressure chamber. Experimental results are summarized as follows: 1) Injection pressure influence on the characteristics of spray namely As Injection pressure Is increased, spray angle is decreased but spray penetration and spray tip velocity is increased. 2) Spray angle, spray penetration is increased by increasing the fuel pump speed. 3) Ambient pressure plays an important role in spray characteristics.

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Characteristics of Impinging Diesel Spray on the Heated Flat Wall in High Temperature and High Pressure Environments (고온.고압 환경에서 가열평판에 충돌하는 디젤분무의 특성)

  • Im, Gyeong-Hun;Lee, Bong-Su;Kim, Jong-Hyeon;Gu, Ja-Ye
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.25 no.5
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    • pp.627-633
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    • 2001
  • Characteristics of a diesel spray impingement with the variation of ambient temperature, wall temperature and ambient pressure were investigated through shadowgraphy method by using high speed camera. The radial penetration of spray was increased with ambient temperature and wall temperature. It is resulted from the decrease of ambient gas density caused by the increase of temperature. The height of spray was also increased with ambient temperature and wall temperature, because the height of stagnate region is noticeably increased, although height of wall jet vortex is decreased. At the same ambient pressure, the area ratio of impinging spray of room temperature environment to high temperature environment was increased, as the temperature difference between room temperature and high temperature increases. And the increment of area ratio was higher at low ambient pressure than high ambient pressure.