• 한국산업보건학회지
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• 제25권4호
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• pp.542-553
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• 2015

Objectives: Many types of dust collector are used for industrial ventilation, with the most common types being the cylinder bag filter system, rectangular bag filter system and cylinder type cartridge filter system. The cylinder type cartridge bag filter, which has more filtering area than other types of bag filter, can increase the pulse time and extend the useful life of the filter. This can save operational costs and installation area. Materials: This study used cylinder type cartridge bag filter equipment and tested the impact of vibration level and filter pressure with different pulse jet cleaning conditions. The final, cleaning efficiency was calculated through input dust mass and cleaning dust mass Conclusions: Two optimum cleaning condition groups were found. The first condition group was $3kgf/cm^2$ pulse pressure, 15 cm pulse distance, 0.2 s pulse time with an H-10 type nozzle. The second condition group was $3kgf/cm^2$ pulse pressure, 15 cm pulse distance, 0.3 s pulse time with an H-10 type nozzle.

• 한국항공우주학회지
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• 제32권10호
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• pp.112-117
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• 2004

본 연구는 공기역학적 운동에너지를 이용하여 점화장치를 구성하는데 따른 해석과 실험에 관한 연구로써 공기역학 점화기는 크게 노즐과 공명관으로 구성되어 있다. 압축가스가 노즐을 통과하여 공명관으로 유입되며, 이때 노즐과 공명관사이에 압력맥동이 발생한다. 이러한 압력맥동에 의한 운동에너지는 일정한 조건하에 공명관 내부에서 열에너지로 변화하게 된다. 본 연구에서는 음속노즐과 초음속 노즐을 두개의 각기 다른 공명관에서 실험과 수치해석을 실시하였으며, 노즐표면의 마찰손실과 공기역학 손실을 최소화하는 초음속 노즐의 최적형상을 제시하였다.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2006년도 PARALLEL CFD 2006
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• pp.395-397
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• 2006

Air interlacing serves to protect the yarn against damage, strengthens inter-filament compactness or cohesion, and ensures fabric consistency. The air interlacing nozzle is used to introduce intermittent nips to a filament yarn so as to improve its performance in textile processing. The effect of various interlacing nozzle geometries on the interlacing process was studied. The geometries of interlacing nozzles with single or multiple air inlets located across the width of yarn channels are investigated. The basis case is the yarn channel, with a perpendicular main air inlet in the middle. Other cases have main air inlets, slightly inclined double sub air inlets, The yarn channel cross sectional shapes are either semicircular or rectangular shapes. The compressed impinging jet from the main air inlet hole hits the opposing bottom wall of the yarn channel, is divided into two branches, joins with the compressed air coming out from sub air inlet at the bottom and creates two free jets at both ends of the yarn channel. The compressed air movement in the cross-section consists of two opposing directional vortices. The CFD-FASTRAN flow parallel solver was used to perform steady simulations of impinging jet flow inside of the interlace nozzles. The vortical structure and the flow pattern such as pressure contour, particle traces, velocity vector plots inside of interlace nozzle geometry are discussed in this pater.

• 에너지공학
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• 제13권1호
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• pp.34-39
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• 2004

본 논문에서는 압축공기를 작동매체로 한 저압용 보텍스튜브에 대한 에너지 분리과정을 상세히 연구하였다 먼저 보텍스튜브에서 에너지 분리되어 나오는 온공기와 냉공기의 온도변화에 대하여 실험하였고, 보텍스튜브의 안쪽표면의 최대벽면온도 변화와 보텍스튜브 내의 온도분포를 통하여 보텍스튜브 내 유동장에서의 정체점의 위치에 대한 유용한 정보를 얻게 되었다. 이를 바탕으로 보텍스튜브의 노즐면적비와, 오리피스의 크기에 따른 에너지분리 과정 등을 실험을 통하여 알아보았다. 이러한 기하학적 형상의 변화실험을 통하여 저압용？대형 보텍스튜브의 에너지 분리과정이 고압형\ulcorner소형 보텍스튜브 보다 에너지 분리효과가 증대됨으로 인하여 최적의 노즐면적비와 오리피스지름비가 차이가 있음을 알 수 있었다.

• 한국환경과학회지
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• 제27권3호
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• pp.219-225
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• 2018

This study was conducted to investigate the possibility of utilizing various types of nozzles and gas-liquid mixers to increase the dissolution rate of plasma gas containing ozone generated in a dielectric barrier plasma reactor. After selecting the air atomizing nozzle with the highest gas dissolution rate among the 13 types of test equipment, we investigated the influence of the operating factors on the air atomizing nozzle to determine the optimal plasma gas dissolution method. The gas dissolution rate was measured by a simple and indirect method, specifically, the measurement of KLa instead of direct measurement of ozone concentration, which requires a longer analysis time. The results showed that the KLa value of the simple mix of air and water was $0.372min^{-1}$, Which is 1.44 times higher than that ($0.258min^{-1}$) of gas emitted from a normal diffuser. Among the nozzles of the same type, the KLa value was highest for the nozzle having the smallest orifice diameter. Among the 13 types of devices tested, the nozzle with highest KLa value was the M22M nozzle, which is a gas-liquid spray nozzle. The relationship between water circulation flow rate and KLa value in the experimental range was linear. The air supply flow rate and KLa value showed a parabolic-type correlation, while the optimum air supply flow rate for the water circulation flow rate of 1.8 L / min is 1.38 times.

• 한국추진공학회지
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• 제10권3호
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• pp.41-47
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• 2006

로켓 연소기에서 음향 공명기의 음향 동조에 미치는 평균 유동 및 노즐 감쇠 효과를 수치해석적으로 연구하였다. 본 연구에서는 분사기가 연소실내 음향 감쇠를 위한 공명기로서 사용된다. 연소실내 평균 유동의 마하수가 증가함에 따라 제 1 접선 방향 모드의 공진 주파수가 미약하게 감소하였으나 최적의 분사기 동조 길이는 거의 변화가 없었다. 노즐 감쇠는 공진 주파수나 최적 동조 길이에 영향을 미치지 못하며, 다만 음향 진동 진폭을 변화시킬 뿐이었다. 이러한 결과로부터, 평균 유동과 노즐 감쇠가 음향 공 동조에 미치는 영향은 미미함을 알 수 있었다. 분사기의 장착 개수가 증가할수록 음향 진동 진폭이 감소하였으나, 분사기와 연계된 새로운 음향 모드가 발생함을 알 수 있었다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2833-2838
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• 2007

Recently, small hydropower attracts attention because of its clean, renewable and abundant energy resources to develop. However, suitable turbine type is not determined yet in the range of small hydropower and it is necessary to study for the effective turbine type. Moreover, relatively high manufacturing cost by the complex structure of the turbine is the highest barrier for developing the small hydropower turbine. Therefore, a cross-flow turbine is adopted because of its simple structure and high possibility of applying to small hydropower. The purpose of this study is to examine the optimum configuration of nozzle shape to further optimize the cross-flow hydraulic turbine structure and to improve the performance. The results show that pressure on the runner blade in Stage 1 and velocity at nozzle outlet have close relation to the turbine performance.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.219-220
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• 2006

In this study, m order to develop multilayer ceramics vibrator for ultrasonic nozzle, PMN-PNN-PZT ceramics were fabricated using $Li_2CO_3-Na_2CO_3$ as sintering aids and their piezoelectric and dielectric characteristics were investigated according to the aomunt of PbO. With increasing PbO contents. secondary phases were increased and phase structure were changed from tetragonal structure to rhombohedral structure and also electromechanical coupling factor were linearly decreased. At the composition ceramics with the sintering temperature of $870^{\circ}C$ and 1 mol% excess PbO, density, electromechanical coupling factor, dielectric constant, piezoelectric d constant and mechanical quality factor showed the optimum value of $7.879g/cm^2$, 0.55, 1149, 328pC/N, 1224, respectively for multilayer ceramics vibrator application for ultrasonic nozzle.

• 한국분무공학회지
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• 제16권4호
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• pp.186-194
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• 2011

This study performed the numerical analysis of the internal nozzle flows including cavitation phenomena by using the automated body-fitted grid generator and the multi-fluid model. The effect of grid refinement and the validation of multifluid model were investigated using four computational meshes under two test conditions. The mesh #3 was chosen as the optimum which can reduce the computational time and have good prediction ability to identify the cavitation region simultaneously. In addition, the computed results using multi-fluid model were compared with the reference experimental observations and numerical simulation results using homogeneous equilibrium model. From the distribution of volume fraction and velocity field, the multi-fluid model predicted the internal nozzle flows well when the liquid quality parameters were selected as $1.0{\times}10^{12}$ for initial number density and 25 ${\mu}m$ for bubble diameter.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집A
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• pp.752-757
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• 2001

To reduce stress concentration around the intersection between a spherical pressure vessel and a cylindrical nozzle under various load conditions using less material, the optimization for the distribution of reinforcement has researched. The ranked bidirectional evolutionary structural optimization(R-BESO) method is developed recently, which adds elements based on a rank, and the performance indicator which can estimate a fully stressed model. The R-BESO method can obtain the optimum design using less iteration number than iteration number of the BESO. In this paper, the optimized intersection shape is sought using R-BESO method for a flush and a protruding nozzle. The considered load cases are a radial compression, torque and shear force.