• Title/Summary/Keyword: Flow Type Change

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A Study on the Phenomena of Dust Removal by the Layout Changes in the Turbulent Type Clean Room (난류형 클린룸내의 Layout 변화에 따른 분진제거 특성에 관한 연구)

  • Kim, Yeon-Hui
    • Journal of the Korea Construction Safety Engineering Association
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    • s.41
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    • pp.80-87
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    • 2007
  • The purpose of this paper is to investigate the removal efficiency of fine dusts as the configuration condition of machinery and equipments in Clean Room and to analyze the flowing behaviors of fine dusts as the layout of Clean Room. The layout of the Clean Room was classified into side layout type, 2 center line type and center concentration type layout, and the flow rates used in this research were 0.22m/s, 0.44m/s and0.80m/s. Dust removal efficiency as layout change was decreased 37% for side layout type, 31% for 2 centerline type and 20% for center concentration type layout at the flow rate of 0.22m/s, compared with the state without machinery and equipments in Clean Room. The efficiency was decreased 42% for side layout type,22% for 2 center line type and 8% for center concentration type layout at the flow rate of 0.44m/s, and decreased 20% for side layout type, 18% for 2 center line type and 10% for center concentration type layout at the flow rate of 0.80m/s. According to the result of dust removal behavior, $0.3\mum$, $1\mum$and $3\mum$dust except for $5\mum$showed the higher change of the behavior in side layout type than in center concentration type layout due to the change of air flow. It was confirmed that removal behavior depends on the layout of machinery and equipments as the dust size decreases.

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A Study of Elapsed Time Change on Concrete for Top-Down Method (역타공법 적용을 위한 콘크리트 경시변화 특성 연구)

  • 정근호;이종균;박선길;이영도;정상진
    • Proceedings of the Korea Concrete Institute Conference
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    • 1999.04a
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    • pp.487-492
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    • 1999
  • The purpose of this study to find the mixture of concrete for Top-Down method. Throughout test of elapsed time change and L-type flow, it was proposed basic performance and level of top-down method concrete. When change as to elapsed time is considered, so series of F10 added 10% S.P satisfied slump and demanded flow (60$\pm$5cm), and L-type slump, L-type flow satisfied liquidity, it can be considered basic mixture of designed actual frame later.

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Effect of the Swirl Number of Spinner on the Exhaust Air of the Gun Type Burner (건타입 버너의 토출공기에 대한 선회기의 스월 수 영향)

  • Ko, Dong Guk;Yoon, Suck Ju
    • Journal of ILASS-Korea
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    • v.20 no.2
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    • pp.70-75
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    • 2015
  • Swirl flow in the gun type burner has an impact on the stabilization of the flame, improvement of the combustion efficiency. The swirl flow is created by the spinner which is inside the airtube that guide the combustion air. Gun type burner has generally the inner devices composed electronic spark plug, injection nozzle, combustion device adaptor, and spinner. These inner components change the air flow behavior passing through airtube. So, this study conducted the measurement using by hot-wire anemometer and analyzed effect of the swirl number of spinner on the exhaust air of gun type burner. Turbulence characteristics come up in this study was mean velocity, turbulence intensity, kinetic energy, shear stress and flattness factor of the air flow with the change of the distance of axial direction and tangential direction from the exit of the airtube.

The performance and flow characteristics of a small propeller fan with a back-plate (뒷판이 있는 소형 프로펠러 팬의 성능 및 유동특성)

  • Gang, Sin-Hyeong;Kim, Jin-Gwon;Lee, Seung-Bae
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.20 no.4
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    • pp.1491-1500
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    • 1996
  • Unstable performance deterioration was found on the performance curve of a small propeller fan with a back plate. To investigate this phenomenon and the effects of the back-plate on the performance of the fan, performance tests and flow measurement using 3-hole pitot tube were carried out. Measurements showed that when the flow rate is small, the radial flow dominates, and when the flow rate is large, the axial flow dominates. Performance characteristic of the propeller fan changes from radial to axial type as the flow rate increases. Unstable performance changes are the result of type change of the flow through the fan.

An Experimental Study on Emission Characteristics of a Semi-Bunsen Type Gas Burner (가스보일러용 세미 분젠형 버어너의 배기 특성 연구)

  • Jurng, J.S.;Park, E.S.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.7 no.3
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    • pp.353-358
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    • 1995
  • The emission characteristics of a semi-Bunsen type burner for gas boilers were studied experimentally. The experimental results reveal that nitric oxide emission increases with fuel flow rate. It is linearly proportional to total fue flow rate at a small amount of fuel up to 0.4 liters per minute. It does not change significantly within the range of fuel flow rate from 0.4 to 1.2 liters per minute per nozzle and increases at large fuel flow rate. The carbon monoxide emission reveals to be dependent upon the fuel flow rate per each nozzle and the number of fuel injection nozzles. Diameter of an injection nozzle could have an effect on the emission characteristics of this type of burners. However, there is no marked change in the nitric oxide emission if the total fuel flow rate is same with different nozzle sizes.

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A Study on Flow Characteristics of Branch Type Sparger in Drain Tank for Depressurization (감압용 배수탱크내의 분기형 증기분사기의 유동특성에 관한 연구)

  • 김광추;박만흥;박경석
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.13 no.5
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    • pp.356-367
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    • 2001
  • A numerical analysis on branch type sparger in drain tank for depressurization is performed to investigate the flow characteristics due to the change of design factor. As the result of this study, sparger\\`s flow resistance coefficient(K) is 3.53 at the present design condition when engineering margin for surface roughness is considered as 20%, and flow ratio into branch pipe ($Q_s/Q_i$) is 0.41. The correlation for calculating flow resistance coefficients as design factor is presented. Flow resistance coefficient is increased as section area ratio of branch pipe for main pipe and outlet nozzle diameter of main pipe decreasing, but the effects of branch angle and inlet flow rate of main pipe are small. As the change rate of ($Q_s/Q_i$)becomes larger, the change rate of flow resistance coefficient increases. The rate of pressure loss has the largest change as section area ratio changing. The condition of maximum flow resistance in sparger is when the outlet nozzle diameter ratio of main pipe ($D_e/D_i$) is 0.167, the section area ratio ($A_s/A_i$) is 0.1 and the branch angle ($\alpha$) is 55^{\circ}$.

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A Study on the Phenomena of Dust Removal by the Layout Changes in the Turbulent Type Clean Room (난류형 클린룸내의 Layout 변화에 따른 분진제거 특성에 관한 연구)

  • Kim, Yeon-Hee;Kim, Hong
    • Journal of the Korean Society of Safety
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    • v.21 no.5 s.77
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    • pp.46-52
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    • 2006
  • The purpose of this paper is to investigate the removal efficiency of fine dusts as the configuration condition of machinery and equipments in Clean Room and to analyze the flowing behaviors of fine dusts as the layout of Clean Room. The layout of the Clean Room was classified into side layout type, 2 center line type and center concentration type layout, and the flow rates used in this research were 0.22m/s, 0.44m/s and 0.80m/s. Dust removal efficiency as layout change was decreased 37% for side layout type, 31% for 2 center line type and 20% for center concentration type layout at the flow rate of 0.22m/s, compared with the state without machinery and equipments in Clean Room. The efficiency was decreased 42% for side layout type, 22% for 2 center line type and 8% for center concentration type layout at the flow rate of 0.44m/s, and decreased 20% for side layout type, 18% for 2 center line type and 10% for center concentration type layout at the flow rate of 0.80m/s. According to the result of dust removal behavior, $0.3{\mu}m,\;1{\mu}m\;and\;3{\mu}m$ dust except for $5{\mu}m$ showed the higher change of the behavior in side layout type than in center concentration type layout due to the change of air flow. It was confirmed that removal behavior depends on the layout of machinery and equipments as the dust size decreases.

An Analysis about the Moving Behavior of Students by Simulation on Variation Type in Middle School (시뮬레이션을 활용한 교과교실형 운영 중학교 학생 이동행태 분석)

  • Jeong, Joo-Seong
    • Journal of the Korean Institute of Educational Facilities
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    • v.21 no.3
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    • pp.11-18
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    • 2014
  • This study was carried out to observe movement behavior of students about a change of physical condition in moving space of variation type using simulation technique. The moving pattern of students was checked by SIMULEX program. The width of corridor was adjusted to 2.4m, 3.0m and 3.9m and a flow coefficient of simulation was estimated with the change of width. The wider the width of corridor was, the lower a flow coefficient was, and the difference was large when the width of corridor was narrow. It was also observed that the flow coefficient was relatively high in all types of corridor setup individual locker. Unit occupation area with the change of width was additionally measured, as shown in the results, the occupation density was low when the width of corridor was wide and a stationary time was short.

A Study on the Turbulent Flow Characteristics of Swirl Jets for Improvement of Combustion Efficiency (연소효율 개선을 위한 스월제트의 난류유동 특성에 관한 연구)

  • Ko, Dong Guk;Yoon, Suck Ju
    • Journal of ILASS-Korea
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    • v.19 no.2
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    • pp.75-81
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    • 2014
  • Swirl flow in the gun type burner has a decisive effect on the stabilization of the flame, improvement of the combustion efficiency, and also a reduction of NOx. This swirl flow is created by the spinner which is inside the airtube that guide the combustion air. Gun type burner has generally the inner devices composed nozzle adapter, spark gap ignitor, and spinner. These inner components change the air flow behavior passing through air tube. Meanwhile, turbulent characteristics of this air flow are important to understand the combustion phenomena in the gun type burner, because the mixture of fuel and air are depended on. However, nearly all of the studies have been analyzed the turbulent flow of simplified combustion formation without the inner devices. So, this study conducted the measurement using by hot-wire anemometer and analyzed turbulent flow characteristics of the swirl flow discharged from the air tube with inner devices. Turbulence characteristics come up in this study were turbulence intensity, kinetic energy and shear stress of the air flow with the change of the distance of axial direction from the exit of the air tube.

Numerical analysis of the thermal fluid characteristics of phase change material in can type container (수치해석과 실험을 통한 Can type container 내부 상변화 물질의 열유체적 특성분석)

  • Seung Min Heo;Su Woong Hyun;Hee Jun Jeong;Dong Ho Shin
    • Journal of the Korean Society of Visualization
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    • v.21 no.2
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    • pp.63-71
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    • 2023
  • Energy storage and distribution technologies are emerging as important factors as research on renewable energy continues. Analyzing the thermal flow of phase change material inside a latent heat storage device and to predict the phase change time is an important part for improvement of thermal performance. However, most of the current research is based on the trial-and-error experimental investigation to measure the phase change time. Therefore, in this study, a can-type phase change material container was designed, and the numerical method for analyzing the thermal flow of phase change material was established and validated. The error rate of the phase change time between the numerical and experimental results was within 5%, which proves its reliability. As a result, the phase change finishing times were found to be 78 minutes with inlet fluid temperature of 80℃ during charging process, and 126 minutes with inlet fluid temperature of 9℃ during discharging process.