• Title/Summary/Keyword: Multi Nozzle

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The Effect of Injection Angle and Nozzle Diameter on HCCI Combustion (분사각 및 분공 직경이 예혼합 압축착화 엔진 연소에 미치는 영향)

  • Kook, Sang-Hoon;Kong, Jang-Sik;Park, Se-Ik;Bae, Choong-Sik;Kim, Jang-Heon
    • Transactions of the Korean Society of Automotive Engineers
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    • v.15 no.2
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    • pp.1-7
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    • 2007
  • The effect of injector geometries including the injection angle and number of nozzle holes on homogeneous charge compression ignition (HCCI) engine combustion has been investigated in an automotive-size single-cylinder diesel engine. The HCCI engine has advantages of simultaneous reduction of PM and NOx emissions by achieving the spatially homogenous distribution of diesel fuel and air mixture, which results in no fuel-rich zones and low combustion temperature. To make homogeneous mixture in a direct-injection diesel engine, the fuel is injected at early timing. The early injection guarantees long ignition delay period resulting in long mixing period to form a homogeneous mixture. The wall-impingement of the diesel spray is a serious problem in this type of application. The impingement occurs due to the low in-cylinder density and temperature as the spray penetrates too deep into the combustion chamber. A hole-type injector (5 holes) with smaller angle ($100^{\circ}$) than the conventional one ($150^{\circ}$) was applied to resolve this problem. The multi-hole injector (14 holes) was also tested to maximize the atomization of diesel fuel. The macroscopic spray structure was visualized in a spray chamber, and the spray penetration was analyzed. Moreover, the effect of injector geometries on the power output and exhaust gases was tested in a single-cylinder diesel engine. Results showed that the small injection angle minimizes the wall-impingement of diesel fuel that results in high power output and low PM emission. The multi-hole injector could not decrease the spray penetration at low in-cylinder pressure and temperature, but still showed the advantages in atomization and premixing.

Development of a nanoparticle multi-generator for assessment of inhalation hazard

  • Lee, Sung-Bae;Han, Jeong-Hee;Kim, Tae-Hyun;Cha, Hyo-Geun;Lim, Cheal-Hong
    • Analytical Science and Technology
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    • v.34 no.2
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    • pp.87-98
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    • 2021
  • In this study, we developed the nanoparticle multi-generator by 3D printer fusion deposition modeling (FDM) method that can reliably generate and deliver nanoparticles at a constant concentration for inhalation risk assessment. A white ABS filament was used as the test material, and SMPS was used for concentration analysis such as particle size and particle distribution. In the case of particle size, the particle size was divided by 100 nm or less and 100 to 1,000 nm, and the number of particles concentration, mass concentration, median diameter of particles, geometric average particle diameter, etc were measured. The occurrence conditions were the extruder temperature, the extruding speed of the nozzle, and the air flow rate, and experiments were conducted according to the change of conditions including the manufacturer's standard conditions. In addition, the utility of inhalation risk assessment was reviewed through a stability maintenance experiment for 6 h. As a result of the experiment, the size of the nanoparticles increased as the discharger temperature increased, as the discharge speed of the nozzle increased, and as the air flow rate decreased. Also, a constant pattern was shown according to the conditions. Even when particles were generated for a long time (6 h), the concentration was kept constant without significant deviation. The distribution of the particles was approximately 80 % for particles of 60 nm to 260 nm, 1.7 % for 1 ㎛ or larger, 0.908 mg/㎥ for the mass concentration, 111 nm for MMAD and 2.10 for GSD. Most of the ABS particles were circular with a size of less than 10 nm, and these circular particles were aggregated to form a cluster of grape with a size of several tens to several hundred nm.

A Study of 2D Micro-patterning of Biodegradable Polymers by MEA (Multi Electrode Array)-based Electrohydrodynamic (EHD) printing (다중 전극 어레이 기반 전기수력학 인쇄 기술을 이용한 생분해성 고분자의 2차원 마이크로 패터닝 연구)

  • Hwang, Tae Heon;Ryu, WonHyoung
    • Particle and aerosol research
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    • v.13 no.3
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    • pp.111-118
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    • 2017
  • Electrohydrodynamic (EHD) printing with the aid of strong electric fields can generate and pattern droplets that are smaller than droplets by other printing technologies. Conventional EHD printing has created two-dimensional (2D) patterns by moving its nozzle or a substrate in X and Y directions. In this study, we aimed to develop an EHD system that can create 2D patterns using a multielectrode array (MEA) without moving a nozzle or substrate. In particular, printing ink mixtures of biodegradable polymers and model dyes was patterned on a thin film made of another biodegradable polymer. Without movement of a nozzle and substrate, stable 2D patterning of minimum $6{\mu}m$ size over a range of about 1 mm away from the nozzle position was achieved by MEA control only. We also demonstrated the possibility of denser 2D pattering of the ink mixtures by moving a target substrate relative to MEA position.

A Study on the Diffuser Inlet Shape of Thermocompressor for MED Desalination Plant (다중효용 담수설비용 열압축기의 디퓨져 입구부 형상에 관한 연구)

  • Jin, Chang-Fu;Song, Young-Ho;Kim, Kyung-Keun;Park, Gi-Tae;Chung, Han-Shik;Choi, Du-Youl
    • Journal of Advanced Marine Engineering and Technology
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    • v.32 no.6
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    • pp.869-876
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    • 2008
  • A thermocompressor is the equipment which compresses a vapor to a desired discharge pressure. Since it was first used as the evacuation pump for a surface condenser, it has been widely adopted for energy saving systems due to its high working confidence. In the present study, the geometrical analysis of the shape between the jet nozzle and the diffuser inlet, the drag force was calculated by means of the integrated equation of motion and the computational fluid dynamic (CFD) package called FLUENT. The computer simulations were performed to investigate the effects by the various suction flow rates, the distance from jet nozzle outlet to the diffuser inlet and the dimensions of the diffuser inlet section through the iterative calculation. In addition, the results from the CFD analysis on the thermocompressor and the experiments were compared for the verification of the CFD results. In the case of a jet nozzle, the results from the CFD analysis showed a good agreement with the experimental results. Furthermore, in this study, a special attention was paid on the performance of the thermocompressor by varying the diffuser convergence angle of $0.0^{\circ}$, $0.5^{\circ}$, $1.0^{\circ}$, $2.0^{\circ}$, $3.5^{\circ}$ and $4.5^{\circ}$. With the increase of the diffuser convergence angle. the suction capacity was improved up to the degree of $1.0^{\circ}$ while it was decreased over the degree of $1.0^{\circ}$.

A Defect Inspection Algorithm Using Multi-Resolution Analysis based on Wavelet Transform (웨이블릿 다해상도 분석에 의한 디지털 이미지 결점 검출 알고리즘)

  • Kim, Kyung-Joon;Lee, Chang-Hwan;Kim, Joo-Yong
    • Textile Coloration and Finishing
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    • v.21 no.1
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    • pp.53-58
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    • 2009
  • A real-time inspection system has been developed by combining CCD based image processing algorithm and a standard lighting equipment. The system was tested for defective fabrics showing nozzle contact scratch marks, which were one of the frequently occurring defects. Multi-resolution analysis(MRA) algorithm were used and evaluated according to both their processing time and detection rate. Standard value for defective inspection was the mean of the non-defect image feature. Similarity was decided via comparing standard value with sample image feature value. Totally, we achieved defective inspection accuracy above 95%.

Endurance of Pneumatic Valve with a Multi-bender PZT Actuator (적층 벤더형 압전식 공압밸브의 내구 특성)

  • Yun, So-Nam;Park, In-Sub
    • Journal of Power System Engineering
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    • v.18 no.2
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    • pp.31-36
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    • 2014
  • In this paper, pneumatic valve which consists of valve body, valve controller, nozzle and a multi-bender PZT actuator was suggested and fabricated. The fabricated pneumatic valve was experimented for performance evaluation. From the experimental results, we know that the flow rate of the suggested valve is 23 lpm at the pressure difference of 1bar and the maximum flow rate is 30 lpm at the pressure difference of 4 bar. The flow rates after endurance test of 9.8 million were 22.57 lpm and 28.62 lpm at the pressure difference of 1bar and 4bar, respectably. Finally, it was verified that the B10 life of the suggested pneumatic valve is over 50 million.

Automatic Inspection Technology for Small Bore Penetration Nozzle in High Radiation Area of Nuclear Power Plant (원자력발전 고방사선구역 소구경 노즐에 대한 자동화검사 기술)

  • Ryu, Sung Woo;Yoon, Kee Bong;Jeon, Gyu Min;Seong, Un Hak
    • Journal of the Korean Society for Nondestructive Testing
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    • v.36 no.6
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    • pp.504-509
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    • 2016
  • Defects in dissimilar metal welds are reported to be on the increase during the operating lifespan and aging of nuclear power plants. In Korea, reported cases of defects due to dissimilar metal welds include the drain nozzle of a steam generator and RCS hot tube sampling nozzles. Therefore, there is an urgent need to develop a reliable automated nondestructive inspection technique and a system for the inspection of dissimilar metal welds of small diameter nozzles in a high radiation area of a nuclear power plant. In this study, to ensure effective defect inspection of small diameter nozzles (RCS high-temperature tube sampling nozzle) of a nuclear power plant, three different methods were developed. These include: (1) optimum inspection probe design by beam simulation, (2) multi-directions UT optimum inspection technique for the inspection of small diameters of different welded parts, and (3) remote control automatic inspection system. The developed technique and systems have been verified to be suitable for use in the inspection of defects in smaller diameter nozzles in nuclear power plants.

Flow and Heat Transfer Characteristics of a Multi-Tube Inserted Impinging Jet (노즐출구에 삽입된 다중관에 의한 충돌제트의 유동 및 열전달 특성)

  • Hwang, Sang-Dong;Cho, Hyung-Hee
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.28 no.2
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    • pp.135-145
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    • 2004
  • An experimental study is conducted to investigate the flow and heat transfer characteristics of a multi-tube inserted impinging jet. Four different multi-tube devices are tested for various nozzle-to-plate distance. Flow visualization by smoke-wire method and velocity measurements using a hot-wire anemometer are applied to analyze the flow characteristics of the multi-tube insert impinging jet. The local heat transfer coefficients of the multi-tube inserted impinging jet on the impingement surface are measured and the results are compared to those of the conventional jet. In multi-tube inserted system the multi-tube length plays an important role in the flow and heat transfer characteristics of the jet flow. With multi-tube insert of I3d4 and I6d4 which has relatively longer tube length than the multi-tube-exit of I3d1 and I6d1, the flow maintains its increased velocity far downstream due to interaction between adjacent flows. For the small H/D of 4, the local heat transfer coefficients of multi-tube inserted impinging jet are much higher than those of the conventional jet because the flow has higher velocity and turbulent intensity by the use of the multi-tube device. At large gap distance of H/D=12, also higher heat transfer rates are obtained by installing multi-tube insert except multi-tube insert of I3d1.

The Study for Improving the Combustion in a D.I. Diesel Engine using Multi-cavity Piston (Multi-cavity Piston에 의한 디젤기관의 연소성 향상에 관한 연구)

  • Park, Chul Hwan;Bang, Joong Cheol
    • Journal of the Korean Society of Combustion
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    • v.20 no.3
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    • pp.13-20
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    • 2015
  • The performance of a direct-injection diesel engine often depends on the strength of swirl or squish, the shape of combustion chamber, the number of nozzle holes, etc. This is natural because the combustion in the cylinder was affected by the mixture formation process. Since the available duration to make the mixture formation of air-fuel is very short, it is difficult to make complete mixture. Therefore, an early stage of combustion is violent, which leads to the weakness of noise and vibration. In this paper, the combustion process of a common-rail diesel engine was studied by employing two kinds of pistons. One has several cavities on the piston crown to intensify the squish during the compression stroke in order to improve the atomization of fuel, we call this multi cavity piston in this paper. The other is a toroidal single cavity piston, generally used in high speed diesel engines. To take photographs of flame and flaming duration, a four-stroke diesel engine was remodeled into a two-stroke visible single cylinder engine and a high speed video camera was used.