• Title/Summary/Keyword: 분사압

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Characteristics of Unielement Injector Combustion with Flow rates and Chamber Pressures (유량 및 연소압에 따른 액체로켓 단위분사기 연소특성 변화)

  • Moon Il-Yoon;Kim Jong-Gyu;Han Yeoung-Min;Yoo Jin;Lee Yang-Seok;Ko Young-Sung
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2005.11a
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    • pp.247-250
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    • 2005
  • In the case of appling a unielement injector developed for a full scale liquid rocket combustor, a operating condition or configuration of the injector is changed by combustion pressure, arrangement and injector quantity of a full scale liquid rocket combustor. In order to verify application, swirl coaxial injectors propelled by jet-A1 and liquid oxygen are tested at different conditions of a combustion pressure, a flowrate and an injector length. As a test result, the application of the present swirl coaxial injectors is excellent because an efficiency of a characteristic velocity is increased at the each test condition beyond that variation of dynamic pressure intensity is small.

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Effect of Injection Pressure and Injection Timing on Combustion Characteristics of Spray-Guided Direct-Injection Spark-Ignition Engine under Lean Stratified Combustion Operation (성층희박연소 운전조건에서 분사압과 분사시기에 따른 분무유도식 직접분사 가솔린엔진의 연소특성)

  • Oh, Hee-Chang;Lee, Min-Seok;Park, Jung-Seo;Bae, Choong-Sik
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.35 no.10
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    • pp.981-987
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    • 2011
  • In this study, single cylinder engine experiment was carried out to investigate combustion characteristics spray guided direct injection spark ignition engine. In the result of engine experiment, it was shown that flammable window of injection timing was existed. The combustion efficiency increased with retarding injection timing, reaching a peak value, subsequent to decrease again. These results were likely due to the effect of ambient pressure on stratified-premixed mixture preparation. 150 bar injection pressure condition and retarded injection timing from the best combustion efficiency injection timing showed the highest IMEP value due to the advanced combustion phase of the maximum combustion efficiency condition. HC emission showed same trend of combustion efficiency, and smoke emission was increased as injection timing was retarded due to the increased locally rich area in the high ambient pressure. NOx emission showed decreasing trend as injection timing was retarded. This is likely due to the maximum in-cylinder temperature was decreased with retarded combustion phase.

Numerical Simulation on a Reacting Flow Field with Various Injection conditions (소형가스터빈용 인젝터의 분무 특성에 따른 반응 유동장 전산 해석)

  • Kim, Sei-Hwan;Jeung, In-Seuck;Park, Hee-Ho;Na, Sang-Kwon
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2010.05a
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    • pp.300-303
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    • 2010
  • This work shows the result of numerical simulation on a reacting flow by varying atomization properties which can be obtained from a injector for a small and low power aircraft gas turbine engine. Because the atomization properties mainly affect on the performance of the engine, a lot of efficiency tests are needed when a new injector is developed. Nowadays researches has been actively performed using computational analysis. Using commercial package CFD-ACE+, basic studies on the reacting flow field have been conducted. Those results show that the reaction rate is increased when higher pressure and wider angle spray condition are used. More smaller parcels can also enhance the fuel-air reaction.

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Effect of Injector Cooling on Ignition of Cryogenic Spray (분사기 냉각이 초저온 분무의 점화에 미치는 영향)

  • Kim, Do-Hun;Lee, Jin-Hyuk;Koo, Ja-Ye
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.40 no.3
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    • pp.222-229
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    • 2012
  • The cooling of a injector effects on the vapor pressure of cryogenic oxidizer spray, and it decides the phase transition point at the ignition process, when the combustion chamber pressure increases drastically. The phase transition of oxidizer spray affects the ignition characteristics, and several ignition tests with the LOx/$GCH_4$ uni-element coaxial swirl injector was performed in the different initial temperatures of oxidizer injector, in order to investigate the effect of injector cooling on the ignition transient characteristics. At the transition point of oxidizer phase, where the combustion chamber pressure increased over the LOx vapor pressure, the temporary quenching phenomenon of the flame occurred. The lower temperature of chilled down injector and tubing tends to move up the phase transition earlier.

Improment of Diesel Combustion using multiple injection under Cold Start Condition (냉시동 조건에서 디젤 연소 특성 및 연소 개선에 대한 연구)

  • Lee, Haeng-Soo;Lee, Jin-Woo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.4
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    • pp.711-717
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    • 2017
  • Startability and harmful emissions are the main issues in diesel engine development under cold conditions. The characteristics of combustion with multiple injection were investigated under cold start conditions. For quantitative analysis, the in-chamber pressure profile was measured and combustion visualization using direct imaging was accomplished. With multiple injection, the peak in-chamber pressure and heat release rate were increased compared to single injection. In addition, the period of flame luminosity detection was shortened using multiple injection. Combustion by main injection was improved with an increase in heat released by pilot combustion when the pilot injection quantity was increased. Finally, an increase in injection pressure also showed the possibility of combustion improvement. On the other hand, an increase of in the pilot injection quantity and injection pressure can cause an increase in harmful emissions, such as HC and CO due to wall wetting. Therefore, more sensitive calibration will be needed when applying a multiple injection strategy under cold start conditions.

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.

Study of Flow Discharging Characteristics of Injectors at Fuel Rich Conditions (연료 과농 환경에서 분사기 유량 통과 특성 연구)

  • Seo, Seong-Hyeon;Lim, Byoung-Jik;Kim, Mun-Ki;Ahn, Kyu-Bok;Kim, Jong-Gyu;Choi, Hwan-Seok
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2010.11a
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    • pp.9-12
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    • 2010
  • This paper discusses experimental data for the assessment of flow discharging characteristics of double swirl coaxial injectors operating at fuel-rich conditions. Combustion tests employing liquid oxygen and kerosene (Jet A-1) were conducted and a discharge coefficient was utilized for defining flow characteristics. A mass flow rate, a pressure, and a temperature were measured to estimate discharge coefficients. Fuel injectors revealed a fixed value of a discharge coefficient regardless of matched LOx injector design, chamber pressure, and mixture ratio. However, oxidizer injectors showed varying discharging coefficients depending on chamber pressure and mixture ratio. Flame structure variations seem to affect flow discharging characteristics of the oxidizer side.

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Field Applications of Carbon Dioxide Pellet for Underground Pipe Cleaning (지중 매설관의 세정을 위한 카본 다이옥사이드 펠릿의 현장 적용성 검토)

  • Choi, Jae-Soon
    • Journal of the Korean Geosynthetics Society
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    • v.16 no.4
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    • pp.75-82
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    • 2017
  • In this study, a new cleaning method using carbon dioxide pellet in the part of underground pipe cleaning method was proposed and verified. First of all, the commentary of The Society for Protective Coatings was examined in detail to determine the quantitative cleaning effects. Also, field tests were carried out to confirm the application of the new method. In the test, the surface condition of inner pipe after the application of the new method was investigated and two types of nozzles were compared in the tests. Also, the tests to measure the final impact pressure of air and carbon dioxide pellet mixtures were performed to investigate the losses of air pressure were investigated. Through this verification on the new method, it was found that the new method is very efficient for the removal of the rust in the pipe cleaning works. Also, the nozzle with excellent cleaning effect was also selected. As a result, this method will be able to largely contribute to the recycling of $CO_2$ which is limited to the use as a cooling agent or the storage of waste.

An Experimental Study of Surface Pressure on a Turbine Blade in Partial Admission (분사영역과 터빈익형 위치에 따른 표면압 변화에 관한 실험적 연구)

  • Choi, Hyoung-Jun;Park, Young-Ha;Kim, Chae-Sil;Cho, Soo-Yong
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.39 no.8
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    • pp.735-743
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    • 2011
  • In this study, the distribution of surface pressure was measured in a steady state on a turbine blade which was moved the injected region and receded the stagnation region using a linear cascade apparatus. Axial-type blades were used and the blade chord was 200mm. The rectangular nozzle was applied and its size was $200mm{\times}200mm$. The experiment was done at $3{\times}10^5$ of Reynolds number based on the chord. The surface pressures on the blade were measured at three different nozzle angles of $58^{\circ}$, $65^{\circ}$ and $72^{\circ}$ for off-design performance test. In addition, three different solidities of 1.25, 1.38 and 1.67 were applied. From the results, the low solidity caused the low pressure on the blade suction surface at entering region and the reverse rotating force was generated at the low nozzle angle. The positive incidence also made the pressure lower on the suction surface at entering region.

자유류와의 분사 압력비와 분출구 형상에 따른 공기 우산 효과 연구

  • Hwang, Jae-Min
    • Proceeding of EDISON Challenge
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    • 2016.11a
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    • pp.71-73
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    • 2016
  • 기존 우산의 단점을 보완한 발명품, 공기우산이 개발되었다. 하지만 공기우산의 단점인 짧은 사용시간을 보완하기 위해 강우량에 따라 적절하게 공기 분사압을 변화시키는 것뿐만 아니라 공기우산의 사용인원의 조절을 위해 압력비와 분사구 형태에 따른 우산의 효과를 알아보는 것이 실 사용에 중요한 요소일 것이다. 이에따라 본 연구에서는 우산 앞 부분의 분출구 형상과 자유류와의 분사 압력비에 따른 자유류의 방어 능력을 확인해 보았다. 평면 분사구에서 압력비가 1.3, 1.5인 구간에서는 우산의 효과를 나타낼 수 없었고 압력비가 1.5인 구간부터 삼각형 분사구와 육각형 분사구에서 우산의 형태가 나타남을 알 수 있었다. 압력비가 2.0인 구간에서 육각형 분사구의 경우 통상적인 우산의 형상을 보이기 시작하는 것을 알 수 있다.

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