• Title/Summary/Keyword: Orifice Diameter Ratio

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A Study for Energy Separation of Vortex Tube using Air Supply System (I) - the effect of diameter of cold end orifice - (공기공급 시스템에 적용되는 Vortex Tube의 에너지 분리특성에 관한 연구(I) -저온출구 orifice의 직경변화에 의한 영향-)

  • 이병화;추홍록;상희선
    • Journal of the Korean Society of Safety
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    • v.13 no.4
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    • pp.9-18
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    • 1998
  • The vortex tube is a simple device for separating a compressed gaseous fluid stream into two flows of high and low temperature without any chemical reactions. Recently, vortex tube is widely used to local cooler of industrial equipments and air supply system. The phenomena of energy separation through the vortex tube was investigated experimentally. This study is focused on the effect of the diameter of cold end orifice diameter on the energy separation. The experiment was carried out with various cold end orifice diameter ratio from 0.22 to 0.78 for different input pressure and cold air flow ratio. The experimental results were indicated that there are an optimum diameter of cold end orifice for the best cooling performance. The maximum cold air temperature difference was appeared when the diameter ratio of the cold end orifice was 0.5. The maximum cooling capacity was obtained when the diameter ratio of the cold end orifice was 0.6 and cold air flow ratio was 0.7.

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A Comparison of Accuracy Between a Turbine and an Orifice Meter in the Field (현장여건에 따른 터빈 유량계와 오리피스 유량계의 정확도 비교)

  • An, Seung-Hee;Her, Jae-Young
    • 유체기계공업학회:학술대회논문집
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    • 1999.12a
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    • pp.97-105
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    • 1999
  • Orifice flow meters are frequently used for measuring gas flow in gas industry. However, to insure the accuracy of the measurement, a certain length of the meter run at the upstream of the flow meter is required. The objective of this study is to analyze flow measurement errors of the orifice flow meter quantitatively for shorter lengths of the meter runs than those suggested in the standard manuals with variation of diameter ratio( $\beta$ ratio) and flow rate. The test results showed that the flow measurement errors of the orifice meter were inversely proportional to the diameter ratio. In other words, when the diameter ratio is 0.3 and 0.7, the measurement error is $-7.3\%$ and $-3.5\%$, respectively. the main reason of the measurement error is due to the swirl effect from the configuration of the meter run at the upstream of the flow meter. In case the length of the meter run is shorter than that suggested in the standard manuals, the swirl effect is not removed completely and it affects the flow meter's performance. As mentioned above, the less the pipe diameter ratio, the more the flow measurement error. It means that the swirl effect on the orifice meter increases as the $\beta$ ratio decreases.

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Effect of Nozzle Orifice Shape and Nozzle Length-to-Diameter Ratio on Internal and External Flow Characteristics of Diesel and Biodiesel Fuel (노즐 오리피스 형상 및 형상비가 디젤과 바이오디젤 연료의 노즐 내부 및 외부 유동특성에 미치는 영향)

  • Park, Su-Han;Suh, Hyun-Kyu;Lee, Chang-Sik
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.31 no.3 s.258
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    • pp.264-272
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    • 2007
  • The aim of this study is to investigate the effects of nozzle orifice shapes and the nozzle length-to-diameter ratio(L/D) on the nozzle cavitation formation inside the orifice and the external flow pattern. The nozzle used in this work was tested the taper orifice nozzle and the rectangular orifice nozzle which was made from the transparent acrylic acid resin. For studying the effect of the nozzle L/D ratio, it was used to three L/D ratios of 3.33, 10, and 20. The cavitation flow of nozzle was visualized by using the ICCD camera and optical system. This work revealed that the flow rate and discharge coefficient($C_d$) of the taper orifice nozzle was larger than those of the rectangular orifice nozzle at the same injection pressure. The cavitation flow was observed in the nozzle orifice at the low injection pressure and the breakup of liquid jet was promoted as the L/D ratio is decreased. The cavitation of biodiesel fuel was formed at the lower injection pressure than that of diesel fuel because of higher viscosity and density.

Effect of Orifice Diameter Ratio on Unlike Impinging Jet Mixing (액상 충돌 제트의 혼합에 대한 분사공 직경비의 영향)

  • Lee, S.W.;Cho, Y.H.;Yu, B.I.
    • Journal of ILASS-Korea
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    • v.11 no.4
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    • pp.220-227
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    • 2006
  • Experimental studies has been conducted to investigate the effect of orifice diameter ratio on the mixing characteristics of the split element of doublet and triplet elements. The spray characteristics of non-reacting immiscible liquids have been investigated using a patternator. The local volume fraction is measured by use of mean value of each component. This volume measurement represents the mixing characteristics of the liquid, which affect the overall combustion efficiency. The ratio of the orifice diameter, ranging from 1 to 1.5, and that of the jet-momentum, ranging from 0.5 to 6.0, we used. The jet impinging behavior with use of various ratios exhibits substantially different mixing characteristics. Mixing efficiency is maximized when the jet-momentum ratio is increased; this behavior is particularly prominent when the orifice diameter ratio is greater than unity. The split of the triplet element yields better mixing characteristics and is more effective than that of the doublet element in regard to achieving high combustion efficiency. The optimum mixing factor for the triplet element is found to be 0.75, according to our measurement.

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A Study of Straight Pipe Length and Straightener in Orifice Meter Turbine Meter (오리피스 유량계와 터빈 유량계의 직관부길이와 유동안정기에 관한 연구)

  • Her, Jae-Young;An, Seung-Hee;Lee, Kang-Jin;Lee, Seung-Jun
    • 유체기계공업학회:학술대회논문집
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    • 2000.12a
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    • pp.265-271
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    • 2000
  • Orifice meters and turbine meters are frequently used for measuring gas flow in gas industry. However, to insure the accuracy of the measurement, a certain length of the meter run at the upstream of the flow meter is required. The objective of this study is to analyze flow measurement errors of the orifice meter quantitatively for shorter lengths of the meter runs than those suggested in the standard manuals with variation of diameter ratio( $\beta$ ratio) and flow rate and also to analyze flow measurement errors of the turbine meter with and without straightener. The test results showed that the flow measurement errors of the orifice meter were inversely proportional to the diameter ratio. In other words, when the diameter ratio is 0.3 and 0.7, the measurement error is $-7.3\%$ and $-3.5\%$, respectively. the main reason of the measurement error is due to the swirl effect from the configuration of the meter run at the upstream of the flow meter. In case the length of the meter run is shorter than that suggested In the standard, the swirl effect is not removed completely and it affects the flow meter's performance. As mentioned above, the less the pipe diameter ratio, the mon the flow measurement error. It means that the swirl effect on the orifice meter increases as the $\beta$ ratio decreases.

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Numerical Study on Improvement of Mixing Equipment' Plan in a Water Treatment Plant (수리해석을 이용한 정수장내 혼화장치 설계 개선에 관한 연구)

  • Oh, S.Y.;Hyun, D.S.;Oh, J.J.;Lee, S.H.;Lee, N.Y.
    • Proceedings of the KSME Conference
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    • 2001.06e
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    • pp.777-782
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    • 2001
  • In this study, we used In-line orifice mixer for efficient chemicals mixing in water treatment. The method of using In-line orifice mixer has been already proved the improvement of water treatment efficiency. Numerical study was performed using FLUENT, a commercial code, to standard design and production of effective In-line orifice mixer. As variable for exactly standardizing, a proper ratio between an outer diameter of cone and a diameter of pipe, a distance between cone and orifice, a determination of orifice diameter for an optimal mixing, a distance between injection nozzle's position and cone, Numerical study has been performed for optimal standard and analyzed flow field on a basis of turbulent intensity in an orifice downstream.

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Discharge Characteristics of Rotating Orifices with Length-to-Diameter Ratios and Inlet Corner Radii (길이 대 직경 비와 입구 모서리 반경에 따른 회전 오리피스의 송출 특성)

  • Ha, Kyoung-Pyo;Kang, Se-Won;Kauh, Sang-Ken
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.24 no.7
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    • pp.957-966
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    • 2000
  • The effect of rotation on the discharge coefficient of orifices with various length-to-diameter ratios and two different inlet corner radii was studied. Length-to-diameter ratios of the orifices range from 0.2 to 10, while the inlet shapes are square edged, or round edges of radius-to-diameter ratio of 0.5. From the experiment, we found that rotational discharge coefficient and Rotation number, when based on ideal exit velocity of the orifice considering momentum transfer from the rotor, describe the effect of rotation very well. In this study, the discharge coefficients of rotating orifices are shown to behave similar to those of the well-known non-rotating orifices. For both rotating and non-rotating orifices, the discharge coefficients increase with the length-to-diameter ratio until a maximum is reached. The flow reattachments in the relatively short orifices are responsible for the increase. The coefficient then decreases with the length-to-diameter ratio due to the friction loss along the orifice bore. The length-to-diameter ratio that yields maximum discharge coefficient, however, increases with the Rotation number because the increased flow-approaching angle requires larger length-to-diameter ratio for complete reattachment. The length-to-diameter ratio for complete reattachment is shorter for round edged orifices than that of square edged orifices by about a unit length-to-diameter ratio.

Calculations of Pressure Difference in Orifice Flowmeter using CFD (CFD를 이용한 오리피스 유량계의 차압계산)

  • Kim, Hong-Min;Kim, Kwang-Yong;Her, Jae-Young;Ha, Young-Chul
    • 유체기계공업학회:학술대회논문집
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    • 2001.11a
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    • pp.400-403
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    • 2001
  • In this study, commercial CFD code, i.e, CFX-4.3 is used to analyze the flow field and to calculate pressure differences in an orifice flowmeter. Four numerical schemes and five turbulence models are tested. Hybrid scheme and Reynolds stress model show the best performance. Chosen scheme and turbulence model are applied to predict pressure differences through the orifice for the diameter ratios, 0.3, 0.5, and 0.7. And, the results are compared with the experimental data. The results show that the calculation error is inversely proportional to the diameter ratio, and is proportional to the mass flow rate.

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Numerical Study on effective Mixing Chemical Liquid using Hydraulic Energy in a Water Treatment Plant (정수장내 수류에너지를 이용한 액체약품의 효율적인 혼화를 위한 수리해석)

  • Song K. S.;Oh S. Y.
    • 한국전산유체공학회:학술대회논문집
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    • 2001.10a
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    • pp.132-137
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    • 2001
  • We used In-line orifice mixer for efficient chemicals mixing in water treatment. The method of using In-line orifice mixer has been already proved the improvement of water treatment efficiency. Code of computational fluid dynamics for numerical analysis was performed using FLUENT, a commercial code. As variable for exactly standardizing, a proper ratio between an outer diameter of deflector and a diameter of pipe, the distance between deflector and orifice, a determination of orifice diameter fur an optimal mixing, a distance between injection nozzle's position and cone, Numerical study has been performed for optimal standard and analyzed flow field on a basis of turbulent intensity in an orifice downstream.

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A Study on the Control of Shock in the Hydraulic System Using the Fluid Device (유체기구를 이용한 유압계통에서의 충격치 제어에 관한 연구)

  • Lee, Joo-Seong;Lee, Kye-Bock;Lee, Chung-Gu
    • Proceedings of the KSME Conference
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    • 2000.11b
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    • pp.621-626
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    • 2000
  • Reduction in pressure transients may be important in the hydraulic system and necessary to avoid failure and to improve the efficiency of operation. This study addresses the design and use of an orifice to provide the desired control of the hydraulic actuator system. The experimental apparatus is a model of an automobile shift system. Control is accomplished by installing four different diameter ratio of orifices at appropriate locations in the system. Experimental results show that the orifice can be used to obtain the control of shock and the control level depends on the orifice size, orifice type, operating conditions.

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