• Title/Summary/Keyword: air guide

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Analysis of Temperature Rise on the Air-Guide's Position of Wind Power Generator (풍력발전기 Air Guide 위치별 온도상승 해석)

  • Han, Chang-Woo;Kim, Hyun-Jae;Kweon, Ki-Yeoung;Lee, Hahk-Sung
    • 한국신재생에너지학회:학술대회논문집
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    • 2008.10a
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    • pp.282-285
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    • 2008
  • In this paper, the numerical analysis of the model without air-guide was carried out in wind power generator. From numerical results, the temperature rise was not satisfied for the class F insulation and the non-uniformity of temperature distribution was a wide difference in heating elements. To improve these problems, the air-guide was installed in front of the coil head of non-drive end(NDE). The short distance between coil head and air-guide was more effective than long distance in cooling performance. Compared to that of the preliminary design, it was found that the cooling performance of the modification design was improved about 12%.

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Numerical Analysis on Recirculation Generated by Obstacles around a Cooling Tower (냉각탑 주위의 장애물에 의한 재순환 현상에 관한 수치해석)

  • Lee Jung-Hee;Choi Young-Ki
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.18 no.7
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    • pp.578-586
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    • 2006
  • The present study has been conducted to examine the effect of obstacles around a cooling tower and an air-guide to prevent recirculation. In order to analyze the interaction between external flow and cooling tower exit flow, the external region as well as the cooling, tower are included in computational domain. Two dimensional analysis is performed using the finite volume method with non-orthogonal and unstructured grid system. The standard ${\kappa}-{\varepsilon}$ turbulence model is used. To investigate the recirculation phenomena, flow and temperature fields are calculated with three approaches such as, the distance between cooling tower and obstacle, the allocated geometrical type, and the effect of height of obstacle. In addition, the air-guide is considered in the current computation. The mean recirculation rate increases with the height of obstacle. The effect of air-guide to reduce the mean recirculation rate is obviously observed.

Three-Dimensional Numerical Analysis on Recirculation Generated by Obstacles Around a Cooling Tower (냉각탑 주위 장애물에 의한 재순환 현상에 관한 3차원 수치해석)

  • Choi, Young-Ki
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.33 no.4
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    • pp.225-234
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    • 2009
  • The present study has been preformed to investigate the effect of obstacles around a cooling tower with air-guide to prevent recirculation. The external region as well as the cooling tower are included in the computational domain to analyze the flow phenomena around a cooling tower accurately. Three-dimensional analysis is performed using the finite volume method with non-orthogonal and unstructured grid system. The standard turbulence model is used to consider the turbulence effect. In order to investigate the recirculation phenomena, flow and temperature fields are calculated with the distance between cooling tower and obstacle, the allocated geometrical type and the air-guide. The moisture fraction rates decrease with increment of the distance between cooling tower and obstacle. The effect of air-guide to reduce the mean recirculation rate is obviously observed.

Effects of a Guide Fin Blade on the Flow Characteristics in a Ventilating Axial Fan (환기용 축류팬의 가이드핀 블레이드 형상변화에 따른 유동특성에 관한 연구)

  • Park, Hong-Kwang;Lee, Jee-Keun;Rho, Byung-Joon
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.19 no.12
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    • pp.874-882
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    • 2007
  • The effects of a guide fin blade on the flow characteristics in a ventilating axial fan were investigated experimentally. The guide fins were setup onto the pressure surface of the blade, and their effects on the flowrate were evaluated. Two types of the guide fin blade were designed. One is the stem fin blade, and the other is the radial fin blade. The stem fin is designed normal to the circumference of a circle, and the radial fin is designed along the circumference of a circle. The results from the guide fin blade fans are compared with that of the blade without guide fins. The position and the geometry of the radial fin setting up on the blade have an effect on the increase of flowrate with the minor sacrifice of rotational speed of the blades. The radial fin positioning at 0.84 times blade diameter shows highest performance in the flowrate. The increase of the blade weight resulting from applying the guide fins shows minor effect on the variation of rotational speed of the blades.

An Experimental Study on Heat Transfer Characteristics of a Thermal Diode Type Enclosure with a Guide Vane

  • Kim, Suk-Hyun;Jang, Young-Keun
    • International Journal of Air-Conditioning and Refrigeration
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    • v.9 no.4
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    • pp.10-16
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    • 2001
  • An experimental study for free convective heat transfer in a thermal diode type enclosure is presented. The thermal diode is a device which allows heat to be transferred in one direction by convection due to density difference of the fluid, and consists of a rectangular-paralle-logrammic enclosure with a guide vane. It is used as heat collection system of solar energy due to its simple construction and low cost. Experimental parameters were guide vane thickness, the inclination angles of the parallelogrammic enclosure, and the lengths of the rectangular enclosure part. The parameter range of the flux Rayleigh numbers was $2.4\times{10}^8$~$9.8\times{10}^8$. The heat transfer rate of this system was shown 10~47% higher than that of other earlier research results without the guide vane. The correlation for fixed $\phi=60^\circ$ was obtained, Nu=0.0037(Ra^*)^{0.429}(d^*)^ {0.050}(Lr/H)^{0.0415}$.

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Design of a Guide Vane for Improving Inside Flow Uniformity of Electrostatic Precipitator (전기집진기 내부의 유동 균일성 향상을 위한 가이드 배인의 최적설계)

  • Noh, Kyung-Wook;Bae, Seong-Jun;Park, Sookhee;Kang, Sunkyun;Lee, Jangmyung
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.62 no.4
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    • pp.523-528
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    • 2013
  • In recent years, many efforts are increasingly being made to conserve the natural environment with enhanced emission standards and air quality standards. Also there are various methods necessary to be researched to minimize the emission of air pollutants. In particular, boilers of industrial facilities are major portions of the air pollution. The front duct which needs to be designed to reduce the gases to the electrostatic precipitator requires a bent tube, a reduction/extend tube and an auxiliary equipment, that is, a guide vane. This paper proposes an optimum design of the guide vane by a case study for electrostatic precipitator's flow uniformity. The operating conditions of this study are as follows: BMCR (Boiler Maximum Continuous Rate) and MGR (Maximum Guaranteed Rate) are 75%, 50%, and 30%; turbulent fluid dynamics model is based upon K-${\varepsilon}$ formulation. Presentation of the computed motion of particles is found to be quite useful to predict the precipitator performance by use CFD (Computational Fluid Dynamics).

A Study on Improvement of Industrial Hood in Ventilation System for Elimination of Harmful Material and Dust (유해물질 및 공업용 분진 제거를 위한 산업용 후드 개선에 관한 연구)

  • Kim, Young-Sun;Oh, Yool-Kwon
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.20 no.4
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    • pp.238-244
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    • 2008
  • This study investigates on the improvement of inhalation effect of hood which attached new device named as "gas-guide-device" in local exhaust ventilation system for the effective elimination of harmful material and dust in manufacturing factory. The gas-guide-device having a diamond shape is composed of width (b) and two sides of a device (X, Y) and its size is selected the industrial hood under application in manufacturing factory after due consideration. In order to investigate the effect of gas-guide-device, numerical and experimental study is performed that the flow velocity is calculated and is measured by a commercial program "COMSOL $Multiphysics^{TM}$" and a hot wire type of anemometer, respectively. The numerical and experimental results are revealed is a similar pattern and flow velocity has improved to hood attached gas-guide-device. Also, the numerical method and result is also verified the dependance. Moreover, the optimum shape and size of gas-guide-device is revealed that the width (b) and the ratio of two sides of gas-guide-device (X, Y) has 125mm and 4 to 6.

An Experimental Study on the Ballistic Accuracy by Air Guide Grooves (공기안내홈이 탄도 정확도에 미치는 실험적 연구)

  • Kim, Junkyu;Kim, Hyungse;Lee, Moonhwan
    • Journal of the Korea Institute of Military Science and Technology
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    • v.19 no.2
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    • pp.195-201
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    • 2016
  • An experimental study has been found the air guide grooves for reducing drag. When a bullet is fired and move in the air, the drag is generated. The vortex which is one of the types of drag hinders the movement of the bullet. To solve this phenomenon, cut a negative grooves that we are called the air guiding grooves at the back of bullet. The grooves bullet has identified that the drag compared to conventional ammunition(KM80 and K193) is reduced to 4.480 and 4.054 : 10 % through a Finite Analysis Program($Ansys^{TM}$). Even pressure center was retreating 0.72 % compared to a Bullet(KM80 and K193). Effect obtained with these results is the accuracy of the grooves bullet in a shooting test was improved by over 32 %(KM80: 2.86, air guide grooves : 1.94) compared to conventional ammunition(KM80 and K193). In addition, muzzle velocity is increased 73 m/s. This is expected to be extended the velocity and effective range of bullet. Also, the velocity of the grooves bullet is increased when moving in the air while the velocity of the bullet(KM80 and K193) is reduced. The gas ejected from the muzzle to be balanced and stable flight of the Bullet. Given these effects, we can reckon the air guide grooves have positive influence.

Development of an Occupational Safety and Health (OSH) Guide for Safely Cleaning Contaminated Machinery, Equipment, and Parts Used in the Electronics Manufacturing Process (전자산업 공정에서 사용한 부품, 기계류 세정(cleaning) 작업 안전보건 가이드)

  • Seunghee Lee;Soyeon Kim;Kyung Ehi Zoh;Yeong Woo Hwang;Kyong-Hui Lee;Kwang Jae Chung;Dong-Uk Park
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.33 no.4
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    • pp.419-426
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    • 2023
  • Objectives: This study aims to develop an Occupational Safety and Health (OSH) guide for the safe cleaning of contaminated machinery, equipment, and parts used in the electronics manufacturing process. Methods: A literature review, field investigations, and discussions were conducted. An initial draft of an OSH guide was developed and reviewed by experts with significant experience in maintenance work in the electronics manufacturing process in order to refine the guide. Results: Workers involved in cleaning processes with chemicals, solvents, and abrasive blasting can face exposure to a wide range of chemicals, abrasives, and noise. Identifying potential risks associated with each cleaning technique was an essential first step toward enhancing safety measures. The OSH guide comprises approximately eleven to twelve sections spanning 20-25 pages. It includes engineering and administrative protocols systematically organized to address the necessary actions before, during, and after cleaning tasks, depending on the technique. It is recommended that airline respirator masks be used in conjunction with an air purification system to ensure adherence to air quality standard "D" for atmosphere level. The use of an oil-free air compressor is advised, preferably a stationary model that does not rely on fuel sources like diesel. Conclusions: This OSH guide is designed to protect workers involved in maintenance activity in the electronics industry and aligns with global standards, such as those from the International Organization for Standardization (ISO) and Semiconductor Equipment and Material International, ensuring a higher level of safety and compliance.

Present State of Self-Rectifying Air Turbines for Wave Energy Conversion

  • Setoguchi, Toshiaki;Takao, Manabu
    • 유체기계공업학회:학술대회논문집
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    • 2003.12a
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    • pp.3-12
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    • 2003
  • This paper reviews the present state of the art on the self-rectifying air turbines, which could be used for wave energy conversion. The overall performances of the turbines under irregular wave conditions, which typically occur in the sea, have been evaluated numerically and compared from the viewpoints of the starting and running characteristics. The types of turbine included in the paper are as follows: (a) Wells turbine with guide vanes (WTGV); (b) turbine with self-pitch-controlled blades (TSCB); (c) biplane Wells turbine with guide vanes (BWGV); (d) impulse turbine with self-pitch-controlled guide vanes (ISGV) and (e) impulse turbine with fixed guide vanes (IFGV). As a result, under irregular wave conditions it is found that the running and starting characteristics of the impulse type turbines could be superior to those of the Wells turbine. Moreover, the authors have explained the mechanism of hysteretic behavior of the Wells turbine and the necessity of links for improvement of the performance of ISGV.

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