• Title/Summary/Keyword: air guide

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Analysis of a Roller Guide Container Stacking System Applicable to the Mobile Harbor (모바일 하버 컨테이너 적재 유도 시스템에서 롤러 가이드 적용 및 해석)

  • Oh, Tae-Oh;Park, Jung-Hong;Kim, Kwang-Hoon;Son, Kwon
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.23 no.9
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    • pp.620-626
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    • 2011
  • The purpose of this study is to evaluate a simulation model of a stacking guidance system (SGS) with a roller guide applicable to the mobile harbor. The study used a small-scale model (1/20) made of wood with rollers in order to compare the dynamic analysis with experiment results. The law of similarity was applied for the validation of the scaled model. In order to construct a more realistic simulation model, the damping coefficient of the dynamic model was adjusted to 0.5 Ns/mm for the wood-to-wood contact condition based on the experimental results. Using this validated model, dynamic simulations were also carried out for containers of 20, 30, and 40 tons. The results showed that the reaction force of the roller guide was increased from 74.7 kN to 91.2 kN as the weight of container increased. For the design of a roller guide for SGS, the results obtained in this study can be used to reduce the reaction force by employing a rubber roller or a highly damped rotational joint.

Analysis on the Pressure Rise Characteristics Caused by Movement of Linear and Rotary Stages using Air Bearings in High Vacuum Environment (고진공 환경용 공기베어링이 적용된 직선, 회전스테이지의 구동에 의한 압력증가 특성분석)

  • Kim, Gyung-Ho;Park, Chun-Hong
    • Journal of the Korean Society for Precision Engineering
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    • v.26 no.8
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    • pp.112-118
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    • 2009
  • A pressure rise is generated while air bearing stages are moving in high vacuum environment. This study analyzed this pressure rise phenomenon theoretically and verified it experimentally using two different kinds of stages - linear and rotary air bearing stages. Results indicate that the pressure rise was caused by additional leakage resulting from stage velocity, along with adsorption and outgassing of gas molecules from the guide rail surface. Though tilting of the stage due to acceleration and deceleration reached several micrometers, it had a negligible effect on pressure rise because the tilting time was very short. Therefore, a rotary air bearing stage showed much less pressure rise than a linear stage because the rotary stage theoretically has nothing to do with the above causes. Additional leakage caused by stage velocity was inevitable if the stage had movements, but pressure rise caused by adsorption and outgassing could be suppressed by improving the surface quality to reduce real surface area, and by coating the guide rail surface with titanium nitride (TiN) which has less adhesion probability of gas molecules. The results also indicate that the pressure rise increased when the air bearing stage operated under high vacuum conditions.

A Numerical Study on Transient Performance Behavior of a Turbofan Engine with Variable Inlet Guide Vane and Bleed Air Schedules (가변 입구 안내익과 블리드 공기 스케줄에 따른 터보팬 엔진에서의 천이 성능특성에 관한 수치연구)

  • Kim, Sangjo;Son, Changmin;Kim, Kuisoon;Kim, Myungho;Min, Seongki
    • Journal of the Korean Society of Propulsion Engineers
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    • v.19 no.5
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    • pp.52-61
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    • 2015
  • This paper performed a numerical study to analyse the transient performance behavior of a turbofan engine with variable inlet guide vane (IGV) and bleed air schedules. The low bypass ratio mixed flow turbofan engine was considered in this study. For modeling the compressor performance with IGV, the performance maps were generated by using a one-dimensional meanline analysis and feed to the engine simulation program. The IGV and bleed air according to the rotating speed were scheduled to satisfy 10% of surge margin at steady-state condition. The transient engine performance analysis was conducted with the schedules. The engine with IGV schedule showed a higher surge margin and lower turbine inlet temperature than the engine with bleed air schedule during the transient period.

ADPI Characteristics of Line Diffuser in a Room with Perimetric Heating Load (측벽 부하가 존재하는 공간에 설치된 라인 디퓨져의 ADPI 특성에 관한 연구)

  • Cho Young-Jin;Kang Seok-Youn;Moon Jong -Sun;Lee Jae-Heon
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.16 no.12
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    • pp.1204-1211
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    • 2004
  • It is difficult to apply a conventional selection guide for diffusers when the diffuser is installed in a perimeter zone, because the air diffusion performance index (ADPI) vs. throw/length (T/L) ratio curve listed in conventional guide does not consider the perimetric heating load through the walls. The objective of this study is to evaluate the effect of the perimetric heating load on the ADPI and propose a selection guide for a proper line diffuser when perimetric heating load exists. The velocity and temperature distributions and the ADPI values are obtained numerically with various heat load ratios and air flow rates. The velocity and temperature distributions and the ADPI values are analyzed by CFD in case of various heat load ratios and air flow rates. Also, ADPI was calculated by those results. The ADPI values by numerical results are compared with an existing experimental data to verify the method for the evaluation of ADPI proposed in a present study. In case of a line diffuser installed at the high side wall, the ADPI decreases according to the increases of the flow rate on every heat load ratio of the present study except 0.75. The ADPI vs. T/L ratio curves have been proposed for the heat load ratios of 0.25, 0.5, 0.75 to guarantee the comport thermal environment when diffusers are installed in perimeter zone.

Design and Fabrication of NRD Guide Filter using Inductive Iris (유도성 아이리스를 이용한 NRD 가이드 필터의 설계 및 제작)

  • 김영수;류원렬;최형동;유영근
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.13 no.8
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    • pp.741-747
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    • 2002
  • In this paper, NRD guide band pass filter with newly designed inductive iris structure is proposed and analyzed with its test results. In case of common NRD guide filter with air gap coupled structure, it was not easy to fabricate and process or each NRD guide dielectric resonator blocks using PTFE. However, in this our research, each dielectric resonator fabricated in a single NRD guide is coupled with inductive iris located on metal plates. The structure is suitable for mass production of a precise and reliable millimeter-wave filter applications. As a result of measurements, designed NRD guide inductive iris filter has superior performance. The pass band is 38.66~39.06 MHz with 400 MHz bandwidth, insertion loss is about 1.4 dB and return loss is below -18 dB.

A Study ono the Type-Change of Automotive Register (차내 환기구 형상변화에 대한 연구)

  • Kim, Jong-Won;Youn, Jong-Gap;Bae, Han;Won, Sung-Pil
    • Transactions of the Korean Society of Automotive Engineers
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    • v.7 no.6
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    • pp.123-134
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    • 1999
  • Nowadays since the automobile is regarded as the third living space, comfortable conditions are required in the passenger compartment. The customer's concern on air-conditioning/heating, ventilation and demisting/defrosting performances has been much increased. Both ventilation and demisting /defrosting performances are directly influenced by register location, shape of regist guide vane, ventilation flow rate, air distribution , and air circulation pattern. Diffuse plume of air from the register is desirable not only to maintain comfort when the comfort when the comfortable condition has been satisfied but to improve demisting /defrosting performance. In this study, experimental and numerical investigation about the flow field of six different register vane types were carried out , respectively. The numerical analysis, based upon the $textsc{k}$-$\varepsilon$ turbulence model , was applied to the air flow field. The results show that the shape of register guide vane should be considered as an important design paramter.

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Numerical Simulation of Duct Flow about Shape and Arrangement of Inlet Guide Vane to Increase the Temperature Uniformity (전치 가이드 베인 배치 및 형상에 따른 보일러 입구 온도분포의 수치해석 연구)

  • Lee, Su-Yun;Shin, Seung-Won
    • Proceedings of the SAREK Conference
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    • 2008.06a
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    • pp.1172-1177
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    • 2008
  • Diverging channel from gas burner exit to the inlet section of Heat Recovery Steam Generator (HRSG) has been re-designed for 1 MW steam supply and power generation system. Three different test geometries have been chosen for the numerical simulation. The existing design for 300 kW HRSG system (CASE B) has been improved by geometry and position changes of inlet guide vanes along with gas velocity entrance angle at the diverging channel inlet (CASE C). Both cases has been compared with the case where hot combustion gas is directly injected without any guide vanes (CASE A). Improved design shows overall uniform velocity and temperature distribution compared to existing design.

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Prediction of Pressure Drop Using the Internal Flow Simulation of Pulse Air Jet Bag Filters (충격기류식 여과집진기의 내부 유동 시뮬레이션 해석을 통한 압력손실 예측)

  • Jang, Kyeong-Min;Jung, Eun-Sang;Suh, Jeong-Min
    • Journal of Environmental Science International
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    • v.29 no.5
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    • pp.457-468
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    • 2020
  • With continuous industrial development, the types, and amount of particulate matter (PM) have been increasing. Since 2018, environmental standards regarding PM have become more stringent. Pulse air jet bag filters are suitable for PM under the 20 ㎛ and, can function regardless of size, concentration and type. Filtration velocity and shape are important factors in the operation and design of the pulse air jet bag filters however, few established studies support this theory. In this research, numerical simulations were conducted based on experimental values and, several methods were employed for minimizing the pressure drop. In the pilot system, as the inlet duct velocity was faster than 19 m/sec, flow was not distributed equally and, re-entrainment occurred due to the hopper directional vortex. The multi-inlet system decelerated the hopper directional vortex by 25 ~ 30%, thereby decreasing total pressure drop by 6.6 ~ 14.7%. The guide vane system blocked the hopper directional vortex, which resulted optimal vane angle of 53°. The total pressure of the guide vane system increased by 0.5 ~ 3% at 1.5 m/min conditions. However, the filtration pressure drop decreased by 4.8 ~ 12.3% in all conditions, thereby reducing the operating cost of filter bags.