• Title/Summary/Keyword: Injection/Suction

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A Study on the Flow Characteristics of Gasoline Spray across the Suction Air Stream (흡입공기분류를 가로지르는 가솔린 분무의 유동 특성 연구)

  • 김원태;강신재;노병준
    • Transactions of the Korean Society of Automotive Engineers
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    • v.7 no.9
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    • pp.63-74
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    • 1999
  • When a fuel was injected with opening the intake valve of a port fuel injection engine, the spray atomization and flow characteristics in the intake port have a strong influence on the mixture formation of a combustion chamber. Thus , this study was to clarify the spray flow characteristics of the air-assist gasoline spray with fine dropkets across the suction air stream in model intake port. For the simulated opening intake valve in port, suction air stream was varied to 10m/s ∼30m/s. And fuel pressur ewas fixed to 300kPa, but air assist pressure was varied to 0∼25kPa for a vairable spray conditions. Spray flow trajectory was investigated by means of laser sheet visualization and the measurements of droplet sizes and velocities were made by PDPA system. Measured droplets within the spray flow field were subdivided into five size groups and then, the flow characteristics of droplet size groups were investigated to the spray across a suction air stream.

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A Study on Injection Mold Design Using Approximation Optimization (근사 최적화 방법을 이용한 사출금형 설계에 관한 연구)

  • Byon, Sung-Kwang;Choi, Ha-Young
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.19 no.6
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    • pp.55-60
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    • 2020
  • The injection molding technique is a processing method widely used for the production of plastic parts. In this study, the gate position, gate size, packing time, and melt temperature were optimized to minimize both the stress and deformation that occur during the injection molding process of medical suction device components. We used a central composite design and Latin hypercube sampling to acquire the data and adopted the response surface method as an approximation method. The efficiency of the optimization of the injection molding problem was determined by comparing the results of a genetic algorithm, sequential quadratic programming, and a non-dominant classification genetic algorithm.

Effect of Suction Pressures with Respect to the Operational Modes Using the Quorum Quenching in the Membrane Bioreactor (생물막 반응기내 quorum quenching을 이용한 운전방식에 따른 흡입 압력의 영향)

  • Min Hyeong, Kim;Eeung Mo, Koo;Hyeok, Kim;Hyun-Suk, Oh;Kun Yong, Chung
    • Membrane Journal
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    • v.32 no.6
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    • pp.465-474
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    • 2022
  • The suction pressure was measured with respect to operational time by the backwashable flat sheet membrane module in membrane bioreactor (MBR). The membrane module having the nominal pore size of 0.2 ㎛ and the effective membrane area of 128cm2 was submerged in MLSS 8,000 mg/L active sludge aqueous solution. The suction pressure was observed with respect to permeation flux and the quorum quenching (QQ) treatment. The effects of FR and SFCO operation methods were compared and analyzed in the experimental groups: vacant bead (VB), BH4 and DKY-1 beads. The suction pressure reduction was the most effective for the permeation flux 40 L/m2 ⋅h with the injection of DKY-1 QQ beads. Also, the suction pressure reduction by the backwashing method was more than twice for using DKY-1 QQ beads.

Effects of Vapor Injection on a Compressor in a Transcritical CO2 Cycle (초임계 CO2 사이클에서 가스 인젝션이 압축기 성능에 미치는 영향)

  • Kim, Woo-Young;Shim, Jae-Hwi;Lee, Yong-Ho;Kim, Hyun-Jin
    • The KSFM Journal of Fluid Machinery
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    • v.10 no.2 s.41
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    • pp.16-21
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    • 2007
  • Potential advantages of using vapor injection in a two stage rotary compressor for a $CO_2$ heat pump water heater system were addressed in this paper by numerical simulation. Vapor separated from a flash tank in the middle of the expansion process can be used for injection into the second stage suction plenum of the compressor to improve the system performance. Vapor injection increases the intermediate pressure between the two stages, thus increasing the first stage compressor work and reducing that of the second stage. As a whole, however, the compressor input power increases due to injected mass flow rate for the second stage. Computer simulation showed that increment of the cooling capacity by vapor injection exceeded that of the compressor work, thus improving the system performance. COP improvement by vapor injection was calculated to be about 5-14% for normal operating conditions. With vapor injection, a maximum COP was found when the displacement volume of the second stage becomes 90-95% of that of the first stage of the compressor.

Effect of Periodic Passing Wake on the Flow Field of a Film-Cooled Flat Plate(I) (주기적인 통과후류가 막냉각되는 평판의 유동장에 미치는 영향(1);압력면과 흡입면에 대한 영향(1))

  • Kuk, Keon;Lee, Joon-Sik;Kauh, Sang-Ken
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.20 no.6
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    • pp.1931-1940
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    • 1996
  • The effect of periodic passing wake on the film-coolant flow issuing normally from a flat plate was investigated experimentally. The passing wake was generated by rotating thin circular bars. Depending on the rotational direction the test plate could be simulated as a pressure surface or a suction surface of a gas turbine blade. The phase-averaged velocity components were measured using an X-type hot-wire probe. The Reynolds number based on the free-stream velocity and injection hole diameter was 23, 500 and the velocity ratio which is the ratio of film coolant velocity to free-stream velocity was 0.5. The velocity-triangle induced by the wake was similar to that induced by the one generated at the blade trailing edge. The vertical velocity component induced by the passing wake, which approaches to the suction surface and moves away from the pressure surface, played a dominant role in the variation of the flow field. The variation in the phase-averaged velocity on the pressure surface was greater than on the suction surface, but the turbulence kinetic energy variation on the suction surface appeared larger than on the pressure surface.

Characteristics of the Gasoline Spray near Impinging Wall in Suction Flow (흡입유동 중 충돌벽면 근처에서 가솔린 분무특성)

  • Kim, Won-Tae;Kang, Shin-Jae;Rho, Byung-Joon
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.24 no.10
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    • pp.1285-1293
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    • 2000
  • In port fuel injection system of SI engines, injected fuel is impinged onto the surface of intake valves and port-wall, and then formed the wall flow under the cold start operation. Wall flows entrained into the cylinder result in the unsteady and nonuniform mixture formation. Therefore, the spray impingement to the wall is considered as having negative influences such as lowering combustion efficiency and causing unburned hydrocarbon emissions. This study investigates the spray characteristics of the wall impinging air-assist spray in suction air flow. A PDPA was used to analyze the flow characteristics under the different conditions such as impingement angle and supplied air. Experimental data concerning the impinging sprays has been obtained in the vicinity of the wall. Measured droplets divided into the pre-impinging droplets which denote as the positive normal velocities and post-impinging droplets that describe as the negative normal velocities for the suction flow. Their velocities, size distributions and SMD are comparatively analyzed before and after the impingement.

A Study on the Engine Performance and Exhaust Emission with Intake Port Methanol Injection in a DI Diesel Engine (직분식 디젤기관의 메탄올 흡기분사에 의한 기관성능과 배기배출물에 관한 연구)

  • 김명수;라진홍;안수길
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.36 no.3
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    • pp.249-256
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    • 2000
  • In order to investigate the effectiveness of methanol, which has high latent heat of evaporation and oxygen contents, for DI diesel engine performance and exhaust emission, the methanol was injected at the suction port of DI diesel engine. The injector used for test was conventional gasoline engine injector and controlled the quantity of methanol per cycle by the power supply controller which designed specially for injector. The results shown that the maximum pressure point was delayed, the value of maximum pressure was decreased, and the concentrations of both NOx and Soot were decreased, as the methanol injection quantity increased, and also the thermal efficiency of engine injected methanol under the high load condition was similar to no methanol injection but under the medium load condition was decreased within the experimental conditions.

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A Study on the Performance Characteristic of Common Rail High Pressure Pump (커먼레일 시스템용 고압펌프의 성능 특성에 관한 연구)

  • Lee, Choon-Tae
    • Journal of Power System Engineering
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    • v.17 no.6
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    • pp.5-10
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    • 2013
  • Diesel engines have the advantages of good fuel efficiency and low emissions. Therefore, car makers have been developed various kinds of diesel engine management system to clean up emissions while improving fuel efficiency. One of them is the common rail system. In the common rail system, diesel fuel is injected into the combustion chamber at ultra high pressures up to 1,800 bar to ensure more complete combustion for cleaner exhaust gas, and highly precise multiple injection reduces NOx emission, combustion noise and vibration. Generally speaking, common rail system consists of booster pump, high pressure pump, common rail, injectors, control valves, and sensors. The high pressure pump receives low pressure fuel from the booster pump and supply high pressure fuel to injectors through the high pressure common injection rail. Therefore, high pressure pump has an important role in common rail system. In this paper, we have investigated the performance of high pressure pump of common rail system.

An investigation of LPG fuel supply method for Liquid phase LPG injection system (LP가스연료 액상공급시스템 특성연구)

  • Kim, C.U.;Oh, S.M.;Choi, S.J.;Kang, K.Y.
    • Journal of ILASS-Korea
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    • v.9 no.2
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    • pp.18-23
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    • 2004
  • An experimental studies of conventional gasoline fuel pump were carried out to obtain fundamental data fur liquid phase LPG injection(LPLi) system. A regenerative type and a roller-vane type of pumps were investigated in various operational condition. The experiments were performed to obtain flow rate of LPG fuel as a function of pressure differences and temperatures. The regenerative pump had too low flow rate at some experimental conditions to use this pump system for LPLi fuel supply system. On the other hand, the roller-vane type pump can be applied to the system only if its check valve is modified. Cavitation might occur in this system which can result in system noise, flow rate variation, and pump durability problem. To solve these problems the system is needed to increase $NPSH_{re}$(required net positive suction head).

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