• 한국입자에어로졸학회지
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• 제15권4호
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• pp.139-148
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• 2019

This study was performed for the application of a high-speed centrifugal cyclone to shale gas mining process. This device uses the centrifugal force to control particles similar to typical cyclones, and the disk located inside the cyclone is forced to rotate using a motor. The pressure difference occurred during the rotating of disk. Hence, inflow rate was generated without a blower fan. In addition, flow rate increased with elevating rpm of motor. The installing the disk in multiple stages on the inner rotor increased the instantaneous disk outlet flow. Hence, the control efficiency of oil particle increased from 1.05% to 31.2%. By modifying the structure of the disk so that the air flow to the opposite direction of the cyclone, the control efficiency of oil particles increased to 81.5%. By increasing the capacity of the motor and the size of the disk, the flow rate was increased to 2.5 ㎥/min because the rpm of motor and pressure difference increased. As rpm of motor increased, the cut-off diameter (d_pc) became smaller. Unlike the Lapple's equation, d_pc was inversely proportional to the effective number of rotations (N_e). The control efficiency was maintained even if the concentration of oil particles increased, for this reason, the higher the oil concentration, the more particles were accumulated and controlled.

• 청정기술
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• 제17권3호
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• pp.259-265
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• 2011

섬유 염색 산업은 공장 주변의 주민들이 악취로 인하여 고통을 받고 있으며 반드시 해결해야할 대기오염 문제이며, 특히 텐타공정에서 발생하는 백연과 악취를 저감하여야 한다. 섬유 염색 산업의 주된 대기 오염물질은 탄화수소로 이루어진 유연제, 가소제, 발수제등을 사용하는 후처리 공정에서 주로 발생한다. 화학 물질이 처리된 섬유를 텐타공정에서 건조하는 동안 섬유에 포함된 오염물질들이 기화하여 대기로 배출된다. 백연은 주로 1 마이크론 미만의 작은 고상 혹은 액상물질로 이루어져 있으며, 텐타공정에서 발생된 오염물질 분자들이, 이들 입자에 붙어서 상당히 먼 거리까지 이동하며 악취를 유발하게 된다. 텐타공정의 악취를 줄이는 가장 효과적인 방법은 이러한 미세한 오일 미스트를 제거하는 것이다. 본 연구에서는 700 CMM의 Full-scale EFC (Electric Fume Collector) 운전을 통하여, 악취 및 백연이 효과적으로 제거되었으며 많은 양의 오일을 회수 할 수 있었다.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2011년도 후기공동학술대회 논문집
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• pp.74-74
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• 2011

• 한국안전학회지
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• 제28권6호
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• pp.23-28
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• 2013

In order to improve extinguishing performance of water mist, many studies of additives have been conducted. In this study, viscosity agent which has the ability to improve extinguishing performance by adhering to the surface on fire was used and fluorine-free surfactant was also added to water to enhance water's wetting ability. This study aimed to verify optimal concentration of extinguishing of additives according to fire source and extinguishing performance by comparison with pure water. In case of wood crib fire, the results show that flame suppression and extinguishing time of sodium alginate 0.4 wt.% are 3.4 times and 2.2 times shorter than those of pure water in 0.2 MPa respectively. It seems that large amount of water adhere to surface on fire, thus cooling effect on surface was enhanced. Also water consumption of sodium alginate 0.4wt.% is up to 65% lower than that of pure water. In case of heptane fire, extinguishing time of cocobetaine 0.1 wt.% is 9.7 times shorter than that of pure water in 0.2 MPa. It is thought that because cocobetaine can block oxygen and suppress oil mist by making emulsion film on fire surface due to a low surface tension. On the other hand, water consumption of cocobetaine 0.1 wt.% is 92% lower than that of pure water.

• 한국화재소방학회논문지
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• 제19권4호
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• pp.37-41
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• 2005

본 연구에서는 미분무수 소화시스템의 변압기에 대한 냉각성능을 기술한다. 재발화를 방지하기 위한 냉각성능은 변압기의 철심으로부터 절연유에 전달되어 축적된 열에너지를 효과적으로 소산시키는 것을 의미한다. 철심이 매우 무겁기 때문에 축소 규모의 변압기를 이용하여 실험을 수행하였고, 이 결과로부터 냉각시간을 결정하기 위하여 상사해석을 수행하였다. 해석 및 실험을 통한 상사법칙으로부터 재발화 방지를 위한 미분무수 소화시스템의 소화시간은 약 12시간으로 나타났다.

• Tribology and Lubricants
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• 제13권3호
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• pp.56-62
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• 1997

Sealing an oil-air mixture plays important roles to have an enhanced lubrication for high speed spindle. High speed spindles require non-contact type sealing mechanism. In this study, an optimum seal design to minimize leakage is concerned in the aspect of flow control. This paper categorizes geometries of mostly used non-contact type seals and analyzes each leakage characteristics to minimize a leakage on sealing area. Effect of minimum clearance and its position are considered according to variation of detail geometry. The estimation of non-leaking property is determined by amount of pressure drop in the leakage path assuming constant leakage flow. To simulate an oil jet or oil mist type high speed spindle lubrication, the working fluid is regarded as two phases that are mixed flow of oil phase and air phase. Both of the turbulence and the compressible flow model were introduced in CFD(Computational Fluid Dynamics) analysis. Design parameters has been induced to minimize leakage in limited space, and a methodological study on geometrical optimization has been conducted.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.962-967
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• 2003

Recently, environmental pollution has become a serious problem in industry, and many researches have been done in order to preserve the environment. The coolant, which promotes lubrication, cooling and penetration, contains chlorine, sulfur and phosphorus to improve the machining efficiency. These additives, which move around into the air during machining, pollute working. Therefore, many researches on how to reduce the amount of coolant during machining have been carried out. However, to reduce even small amount of coolant causes high temperature of a workpiece and it brings thermal defects. In this study, the experiments of wet & dry grinding using cooling methods (using coolant only, mist and compressed cold air only) are performed to solve the problem of environmental contamination and to get a better surface integrity of a workpiece by comparing surface roughness, roundness and residual stress.

• 한국정밀공학회지
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• 제14권4호
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• pp.56-63
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• 1997

Sealing of lubricant-air mixture in the high performance machining center is one of most the important characteristics to carry out enhanced lubrication. High speed spindle requires non-contact type of sealing mechanism. Evaluating an optimum seal design to minimize leakage is concerned in the aspect of flow control. Effect of geometry and leakage path are evaluated according to variation of sealing geometry. Velocity, pressure, turbulence intensity of profile is calculated to find more efficient geometry and variables. This offers a methodological way of enhancement seal design for high speed spindle. The working fluid is regarded as two phases that are mixed flow of oil phase and air phase. It is more reasonable to simulate an oil jet or oil mist type high speed spindle lubrication. Turbulence and compressible flow model are used to evaluate a flow characteristic. This paper considers a design effect of sealing capability of non- contact type seals for high speed spindle and analyzes leakage characteristics to minimize a leakage 7 on the same sealing area.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1997년도 제25회 춘계학술대회
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• pp.176-180
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• 1997

Evaluating an optimum seal design to minimize leakage is concerned in the aspect of flow control. Flow is characterized into five categories according to its leakage path. Effect of geometry and leakage path are evaluated according to variation of sealing geometry. To simulate an oil jet or oil mist type high speed spindle lubrication, the working fluid is regarded as two phases that are mixed flow of oil phase and air phase. Both of the turbulence and the compressible flow model were introduced in CFD(Computational Fluid Dynamics) analysis. This offers a methodological way of enhancement seal design for high speed spindle.

• 한국화재소방학회논문지
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• 제24권4호
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• pp.62-68
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• 2010

우리나라의 목조문화재는 구조적 특성상 화재에 매우 취약하고, 최근 들어 산불 및 방화 등의 이유로 많은 문화재들이 화재로 손실되고 있다. 따라서 본 연구 개발은 소량의 소화용수 사용이 가능한 중저압용 미분무 노즐과 그 패키지 소화 시스템을 개발하여 물로 인한 최소한의 피해와 최대의 소화효과와 더불어 최고의 화재안전 시스템을 개발하였다. 목조문화재 건축물의 특성을 고려하여 건축물의 내부와 외부에서 각각 적용 가능한 두 가지 형태의 중저압 미분무 노즐을 개발하였다. 외부용 노즐은 13~14bar의 압력에 서 30~35l/min의 유량을 갖고 있으며, 내부용 노즐은 14~15bar의 압력에서 25~30l/min 유량을 갖는 노즐을 설계 개발하였다. 개발된 노즐의 성능을 평가하기 위하여 궁궐 모양의 대표적인 목조문화재 실무크기인 가로 4.9m, 세로 4m, 높이 6.6m의 모형을 목재로 제작하였고 화재 시나리오를 만들어 실증화재 소화 실험을 실시하였다. 실증화재 실험결과 $200{\mu}m$의 물방울 입자 크기를 갖는 중저압 노즐이 한 적응성이 있는 것으로 나타났으며, 완전소화에는 실패하더라도 소방대가 출동할 때까지 연소확대가 되지 않도록 화재를 억제해 줄 수 있을 것으로 나타났다.