• Title/Summary/Keyword: injection pressure

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A Study on the Pressure drop Variance of Pulse interval, injection distance in Pulse Air Jet Type Bag Filter (충격기류식 여과집진장치의 펄스간격 밀 분사거리에 따른 압력손실변화에 관한 기초 연구)

  • Seo, Jeong Min;Choe, Geum Chan;Park, Jeong Ho
    • Journal of Environmental Science International
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    • v.13 no.3
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    • pp.223-232
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    • 2004
  • The change of pressure drop according to the change in the inlet concentration, pulse interval, and injection distance of pulse air jet type bag filters, and the effect of venturi installation are as follows. The pressure drop with the range of 30 to $50mmH_2O$ varies according to the injection distance with 30, 50, 70, 90sec and the inlet concentration of venture built-in fabric filters. For the lower concentration of 0.5g/㎥ and 1g/㎥, the pressure $drop(\DeltaP)$ was stable 60 to 90minutes after operation. For the higher concentration of 3g/㎥, as $\DeltaP$ continues to go up, pulse interval should be set shorter than 30 seconds. The pressure drop with the injection distance of 1l0mm, when inlet dust concentration is 0.5g/㎥ or 1g/㎥, is 1.3 to 2 lower than with the injection distance of 50, 160, and 220mm, which means that the inflow amount of the secondary air by the instant acceleration is large. The injection distance of 2g/㎥ and 3g/㎥ has the similar pressure distribution. The higher inlet concentration is, the more important pulse interval is than injection distance. The pressure drop has proved to be larger when inlet concentration is lower and injection distance closer, on condition that the venturi is installed. The change in the pressure drop was smallest when injection distance was 50mm, followed by 220mm, 160mm, and 110mm.

Design Performance Analysis of Solid Oxide Fuel Cell / Gas Turbine Hybrid Systems Considering Steam Injection (스팀분사를 고려한 SOFC/GT 하이브리드 시스템의 설계 성능 비교 분석)

  • Park, Sung-Ku;Kim, Tong-Seop
    • Proceedings of the KSME Conference
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    • 2007.05b
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    • pp.3224-3229
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    • 2007
  • This study aims to analyse the influence of steam injection on the performance of hybrid systems combining a solid oxide fuel cell and a gas turbine. The steam is generated by recovering heat from the exhaust gas. Two system configurations, with difference being the operating pressure of the SOFC, are examined and effects of steam injection on performances of the two systems are compared. Two representative gas turbine pressure ratios are simulated and a wide range of both the fuel cell temperature and the turbine inlet temperature is examined. Without steam injection, the pressurized system generally exhibits better system efficiency than the ambient pressure system. Steam injection increases system power capacity for all design cases. However, its effect on system efficiency varies much depending on design conditions. The pressurized system hardly takes advantage of the steam injection in terms of the system efficiency. On the other hand, steam injection contributes to the efficiency improvement of the ambient pressure system in some design conditions. A higher pressure ratio provides a better chance of efficiency increase due to steam injection.

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Study on Macroscopic Spray and Spray Pattern Characteristics of Gasoline Direct Injection Injector for the Variation of Injection Pressure (분사압력 변화에 따른 가솔린 직접분사 인젝터의 거시적 분무와 분무패턴 특성에 관한 연구)

  • Park, Jeonghyun;Park, Suhan
    • Journal of ILASS-Korea
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    • v.23 no.1
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    • pp.22-29
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    • 2018
  • The purpose of this study is to investigate the macroscopic spray characteristics and spray pattern of a gasoline direct injection (GDI) injector according to the increase of injection pressure. The macroscopic spray characteristics, such as a spray tip penetration and spray angle, were measured and analyzed from the frozen spray images, which are obtained from the spray visualization system including the high-speed camera, light-source, long-distance microscope (LDM). The spray pattern was analyzed through the deviation of the center of the spray plum and images were acquired using Nd: YAG Laser and ICCD(Intensified charge coupled device) camera. From the experiment and analysis, it revealed that the injection pressure have a significant influence on the spray tip penetration and spray pattern. However, the injection pressure have little influence on the spray angle. The increase of injection pressure induced the reduction of a closing delay. In addition, the deviation of spray center increase with the increase of injection pressure and the distance from a nozzle tip.

A Study on Stratified Charge GDI Engine Development - Combustion Analysis according to the Variations of Injection Pressure and Load - (연소실 직접분사식 성층급기 가솔린기관 개발에 관한 연구 - 연료분사압력과 부하변동에 따른 연소특성 해석 -)

  • Lee, Sang Man;Jeong, Young Sik;Chae, Jae Ou
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.22 no.9
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    • pp.1317-1324
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    • 1998
  • In general, DI gasoline engine has the advantages of higher power output, higher thermal efficiency, higher EGR tolerance and lower emissions due to the operation characteristics of increased volumetric efficiency, compression ratio and ultra-lean combustion scheme. In order to apply the concept of stratified charge into direct injection gasoline engine, some kinds of methodologies have been adapted in various papers. In this study, a reflector was adapted around the injector nozzle to apply the concept of stratified charge combustion which leads the air-fuel mixture to be rich near spark plug. Therefore, the mixture near the spark plug is locally rich to ignite while the lean mixture is wholly introduced into the combustion chamber. The characteristics of combustion is analyzed with the variations of fuel injection pressure and load in a stratified -charge direct injection single cylinder gasoline engine. The obtained results are summarized as follows ; 1. The MBT spark timing approached to TDC with the increase of load on account of the increase of evaporation energy, but has little relation with fuel injection pressure. 2. The stratification effects are apparent with the increase of injection pressure. It is considered by the development of secondary diffusive combustion and the increase of heat release of same region, but proceed rapidly than diesel engine. Especially, in the case of high pressure injection (l70bar) and high load (3.0kgf m), the diffusive combustion parts are developed excessively and results in the decrease of peak pressure than in the case of middle load. 3. The index of engine stability, COVimep value, is drastically decreased with the increase of load. 4. To get better performance of DI gasoline engine development, staged optimizaion must be needed such as injection pressure, reflector, intake swirl, injection timing, chamber shape, ignition system and so on. In this study, the I50bar injection pressure is appeared as the optimum.

Pressure distributions in the cavity in injection molding for various operational conditions (사출성형조건에 따른 캐비티의 압력분포)

  • Kim J. M.;Jun J. H.;Lyu M. Y.;Hwang H. S.;Lee J. W.;Lee S. H.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2005.10a
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    • pp.214-219
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    • 2005
  • Pressure distribution in the cavity during injection molding affects part quality. In this study pressure distributions in the runner, near gate in the cavity, and end of ail in the cavity have been measured using direct pressure sensors for various molding conditions. Molding conditions were injection speed, injection pressure, packing time from filing stage, and packing pressure. Through experiments it was realized that the packing time from filling stage and packing pressure are the dominant factors on the part quality such as part shrinkage. Experimental results have been compared with computer simulations.

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Mixing Augmentation of Transverse Injection of Fuel in SCRamjet Engine (스크램제트엔진 연료수직분사의 혼합특성 개선에 관한 수치연구)

  • Kim, Young-Jin;Lee, Sang-Hyeon
    • Journal of the Korean Society of Combustion
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    • v.4 no.1
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    • pp.117-129
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    • 1999
  • A method for the mixing augmentation of the transverse injection of fuel in a Scramjet combustor is suggested. Based on the fact that the main factor controlling the mixing characteristics in transverse injection is the effective back-pressure (the pressure around the injection hole) it is tried to make a flow expansion near the injection port in order to reduce effective back-pressure. A three dimensional Navier-Stokes code adopting the upwind method of Roe#s flux difference splitting scheme is used. The k-w SST turbulence model turbulence model is used to calculate the turbulent viscosity. It is shown that the reducing of the effective back-pressure make it possible to increase the penetration distance and to increase the mixing rate without excessive losses of stagnation pressure. Also, it is shown that the streamwise vorticity generated by baroclinic torque has great influences on the mixing process.

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A Computational Study of the Fluidic Thrust Vector Control Using Secondary Flow Injection (2차 유동 분사를 이용한 추력벡터 제어에 관한 수치해석적 연구)

  • Lim, Chae-Min;Kim, Heuy-Dong
    • Proceedings of the KSME Conference
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    • 2003.11a
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    • pp.496-501
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    • 2003
  • Computational study is performed to understand the fluidic thrust vectoring control of an axisymmetric nozzle, in which secondary gas injection is made in the divergent section of the nozzle. The nozzle has a design Mach number of 2.0, and the operation pressure ratio is varied to obtain the different flow features in the nozzle flow. The injection flow rate is varied by means of the injection port pressure. Test conditions are in the range of the nozzle pressure ratio from 3.0 to 8.26 and the injection pressure ratio from 0 to 1.0. The present computational results show that, for a given nozzle pressure ratio, an increase of the injection pressure ratio produces increased thrust vector angle, but decreases the thrust efficiency.

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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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    • 2015.12a
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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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Evaluation of the backfill injection pressure and its effect on ground settlement for shield TBM using numerical analysis (쉴드 TBM 뒤채움압 산정 및 침하영향에 대한 수치해석적 연구)

  • Ahn, Chang-Kyun;Yu, Jeong-Seon;Lee, Seok-Won
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.20 no.2
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    • pp.269-286
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    • 2018
  • Backfill injection pressure in shield TBM affects not only ground settlement but also adjacent underground structures. Therefore, it is essential to estimate a suitable backfill injection pressure in advance in design stage. In this paper, seven suggested equations worldwide to calculate the backfill injection pressure were reviewed and compared. By assuming 6 cases of virtual ground condition, backfill injection pressures were calculated and analyzed. it was confirmed that the backfill injection pressure increases as the depth of overburden increases, but the increasing ratio decreases. The numerical analysis was carried out by applying the calculated backfill injection pressure to investigate the influence of backfill injection pressure on the settlement of surface and crown of tunnel. It was confirmed that the final settlement at the surface and crown of tunnel on the both unsaturated and saturated condition are more influenced by the applied face pressure than the applied backfill injection pressure. In addition, the effect of backfill injection pressure decreases as the depth of overburden increases, and the effect of backfill injection pressure increases as the applied face pressure decreases.

A Study on the Effects of Filling and Packing Phases on the Injection Modeling (사출성형에 대한 충전과 보압과정의 영향에 관한 연구)

  • 김현필;김용조
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2002.04a
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    • pp.112-118
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    • 2002
  • Injection molding process factors such as molding temperature, injection pressure, flow rate and flow velocity, must be controlled properly in filling and packing phases in the injection molding process. In this study, effects of these factors on the injection molding were investigated through the flow analysis fur the filling and packing phases. Molding troubles like flow mark, weld line, sink mark, short shot and warpage can be caused by these injection molding process factors. Among them, the short shot was caused by that the packing pressure could not reach properly to the filling end part in the packing phase and hence the flow rate could not be supplied to the full. In addition, as the flow rate for the volumetric shrinkage during the frozen phase could not be supplied properly by the packing pressure, the short shot appeared. Here, the volumetric shrinkage reduced with increasing the packing pressure and also the warpage of molded part increased with increasing the packing pressure.

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