• Title/Summary/Keyword: Duct system

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Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2013 (설비공학 분야의 최근 연구 동향 : 2013년 학회지 논문에 대한 종합적 고찰)

  • Lee, Dae-Young;Kim, Sa Ryang;Kim, Hyun-Jung;Kim, Dong-Seon;Park, Jun-Seok;Ihm, Pyeong Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.26 no.12
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    • pp.605-619
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    • 2014
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2013. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of fluid machinery, pipes and relative parts including orifices, dampers and ducts, fuel cells and power plants, cooling and air-conditioning, heat and mass transfer, two phase flow, and the flow around buildings and structures. Research issues dealing with home appliances, flows around buildings, nuclear power plant, and manufacturing processes are newly added in thermal and fluid engineering research area. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results for general analytical model for desiccant wheels, the effects of water absorption on the thermal conductivity of insulation materials, thermal properties of Octadecane/xGnP shape-stabilized phase change materials and $CO_2$ and $CO_2$-Hydrate mixture, effect of ground source heat pump system, the heat flux meter location for the performance test of a refrigerator vacuum insulation panel, a parallel flow evaporator for a heat pump dryer, the condensation risk assessment of vacuum multi-layer glass and triple glass, optimization of a forced convection type PCM refrigeration module, surface temperature sensor using fluorescent nanoporous thin film. In the area of pool boiling and condensing heat transfer, researches on ammonia inside horizontal smooth small tube, R1234yf on various enhanced surfaces, HFC32/HFC152a on a plain surface, spray cooling up to critical heat flux on a low-fin enhanced surface were actively carried out. In the area of industrial heat exchangers, researches on a fin tube type adsorber, the mass-transfer kinetics of a fin-tube-type adsorption bed, fin-and-tube heat exchangers having sine wave fins and oval tubes, louvered fin heat exchanger were performed. (3) In the field of refrigeration, studies are categorized into three groups namely refrigeration cycle, refrigerant and modeling and control. In the category of refrigeration cycle, studies were focused on the enhancement or optimization of experimental or commercial systems including a R410a VRF(Various Refrigerant Flow) heat pump, a R134a 2-stage screw heat pump and a R134a double-heat source automotive air-conditioner system. In the category of refrigerant, studies were carried out for the application of alternative refrigerants or refrigeration technologies including $CO_2$ water heaters, a R1234yf automotive air-conditioner, a R436b water cooler and a thermoelectric refrigerator. In the category of modeling and control, theoretical and experimental studies were carried out to predict the performance of various thermal and control systems including the long-term energy analysis of a geo-thermal heat pump system coupled to cast-in-place energy piles, the dynamic simulation of a water heater-coupled hybrid heat pump and the numerical simulation of an integral optimum regulating controller for a system heat pump. (4) In building mechanical system research fields, twenty one studies were conducted to achieve effective design of the mechanical systems, and also to maximize the energy efficiency of buildings. The topics of the studies included heating and cooling, HVAC system, ventilation, and renewable energies in the buildings. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment is mostly focused on indoor environment and building energy. The main researches of indoor environment are related to infiltration, ventilation, leak flow and airtightness performance in residential building. The subjects of building energy are worked on energy saving, operation method and optimum operation of building energy systems. The remained studies are related to the special facility such as cleanroom, internet data center and biosafety laboratory. water supply and drain system, defining standard input variables of BIM (Building Information Modeling) for facility management system, estimating capability and providing operation guidelines of subway station as shelter for refuge and evaluation of pollutant emissions from furniture-like products.

Effects of Different Ventilation Systems on Rearing Growing-finisher and Indoor Environment in a High Rise Hog Building (고상식 돈사내에서 환기시스템별 환경조사 및 육성비육돈 사육 효과)

  • Yoo, Y.H.;Jeong, J.W.;Park, K.H.;Song, J.I.;Ko, Y.G.;Kim, S.W.;Lee, I.B.
    • Journal of Animal Environmental Science
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    • v.16 no.3
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    • pp.193-204
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    • 2010
  • The goal of this study was to develop a high-rise hog building(HRHB) for growing-fattening stages. HRHB was two story building and was suitable for specific environment in Korea. Manure was treated in a first floor and pigs were raised on the slatted second floor. Three ventilation systems - 1) duct inlet to wall exhaust system(V1), 2) eave inlet to wall exhaust system(V2), and 3) ceiling inlet to wall exhaust system(V3) - were used. This experiment was conducted during winter and from summer to fall. Air temperature, air speed, ammonia, hydrogen sulfide in HRHB, and swine growth rate were measured. During winter, air temperature in V1 system tended to be slightly high without any effect of outside air temperature. Maximum temperature from summer to fall was between 33.4 and $33.8^{\circ}C$ and there was no significant difference among systems. Continuously measured daily temperature was lower in V2 system than other systems and the fluctuation of air temperature was high. Air speed in V1 and V2 systems were similar (0.02~0.21 m/s), and was 0.04~0.15 m/s in V3 during winter. From summer to fall, air speed in V1, V2, and V3 systems were 0.10~0.41 m/s, 0.10~0.83 m/s, and 0.11~0.26 m/s, respectively. V2 system showed bigger fluctuation of air speed than other systems. During winter, the highest concentrations of ammonia in V1, V2, and V3 systems were 7.0, 3.5, and 8.7 ppm, respectively. Hydrogen sulfide was not detected. The highest concentrations of ammonia from summer to winter in V1, V2, and V3 systems were 6.1, 2.8, and 5.6 ppm, respectively. Swine growth showed no statistical significance among systems. However, daily weight gain was approximately 4% higher in V1 and V3 than in V2. Feed intake/daily weight gain was approximately 4% higher in V1 than other systems. From summer to fall, daily weight gain in V1 and V3 tended to approximately 3% higher than other systems, and feed intake/daily weight gain was approximately 2% higher in V1 than other systems. Hence, V2 system for the ventilation system of HRHB should not be utilized.

Effective Fan Noise Control Using Active Noise Control (능동소음제어를 이용한 효과적인 팬소음의 제어)

  • Eom Seung-Sin;Shin Inwhan;Lee Soogab
    • Proceedings of the Acoustical Society of Korea Conference
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    • autumn
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    • pp.433-438
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    • 1999
  • This paper describes Active Noise Cancellation/Control(ANC) method that removes the information of the unnecessary noise and doesn't remove the informations of the necessary noise(warning sound, operating sound etc.) for the induced noise of the mechanical system. In this paper, the noise source Is axial fan, and the Feedback Active Noise control method that can effectively control BPF generated from the axial fan is used, and the Filtered-X LMS algorithm for adaptive algorithms is used. The experiments are executed for two case(propagating noise in the duct, emission noise for exterior free field). The part to be removed is BPF noise, and the band-pass filter not to effect to the other frequencies is used. Also, to investigate the effect of the noise reduction for human, we are compared with the results that are controlled for using Loudness before and after. As a results, we are certified that the BPF is decreased only and frequencies outside of BPF are not affected, and we acquire the reduction effects of 6.7 dB Loudness Level, then the frequency to be removed is controlled. Therefore, we can be certified that sound pressure as well as loudness can be effectively decreased for human sound quality

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A study on the burn-in test to accomplish high quality cockpit air of an ultra-sonic aircraft in the early stage of production (생산 초기 초음속 항공기 조종석의 고품질 공기 확보를 위한 burn-in test 연구)

  • Shin, Jae Hyuk;Park, Sung Jae;Seo, Dong Yeon;Jeong, Suheon
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.44 no.10
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    • pp.871-876
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    • 2016
  • Abnormal odor similar with burning smell often appears at the cockpit in the beginning of ultra-sonic aircraft without air filter due to the heating of production materials remained at the bleed air duct. Sources of the odor should be removed by burn-in test before test flight in order to prevent pilot confuses order with emergency such as fire of engine. However, the present method cannot prevent abnormal odor completely at the high altitude flight because maximum temperature of flight is higher than it of burn-in-test. This paper suggests burn-in test improved based on the analysis of thermal conditions of high altitude flight. It is verified that the existing burn-in test cannot cover thermal conditions of high altitude flight due to the discontinuous flow control, high change rate of temperature per unit time and difference between limit temperature of condenser and turbine. In order to overcome the limitations of current methods, the new burn-in test with continuous flow control are suggested. The continuous flow control are achieved by ram air inlet control. The effect of suggested method are verified by ground tests and flight tests. The results show the bleed air temperature can cover the temperature of high altitude flight and prevent abnormal odor at the flight test.

The study of CFD Modelling and numerical analysis for MSW in MBT system (생활폐기물 전처리시스템(MBT)의 동역학적 수치해석 및 모델링에 대한 연구)

  • Lee, Keon joo;Cho, Min tae;Na, Kyung Deok
    • Journal of the Korea Organic Resources Recycling Association
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    • v.18 no.3
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    • pp.77-86
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    • 2010
  • In this study, the model of the indirect wind suction waste sorting machine for characteristics of the screening of waste was studied using computational fluid dynamics and the drag coefficient for the model and the suction wind speed were obtained. The wind separator are developing by installing a cyclone air outlet to the suction blower impeller waste is selective in a way that does not pass the features and characteristics of the inlet pipe of the pressure loss and separation efficiency can have a significant impact on. Using Wind separator for selection of waste in the waste prior research on the aerodynamic properties are essential. For plastic cases, it is reasonable to take the drag coefficient between 0.8 and 1.0, and for cans, compression depending on whether the cans, the drag coefficient is in the range from 0.2 to 0.7. The separation efficiency of waste as change suction speed was the highest efficiency when the suction speed was 25~26 m/s. Shape of the inlet, depending on how the transfer pipe of the duct pressure loss occurs because the inlet velocity changes through the appropriate design standards to allow for continued research is needed.

Wall flow characteristics with static mixer position and housing geometry for preventing urea-salt deposition (우레아염 퇴적 방지를 위한 믹서 위치 및 하우징 형상에 따른 벽면 유동특성에 관한 연구)

  • Lee, Banguk;Lee, Jeekeun
    • Journal of Advanced Marine Engineering and Technology
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    • v.37 no.4
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    • pp.368-377
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    • 2013
  • The Urea-SCR system commercialized shows a remarkable performance to reduce NOx emission in heavy duty diesel engines. However, Urea-water solution injected upstream a mixer, which is set up inside a exhaust pipe to promote exhaust gas-atomized droplet mixing, bumps up against the wall of a exhaust pipe as the droplets flow downstream through the exhaust gas. The urea deposited on the wall of the exhaust pipe is changed into the Urea-salt, resulting in the decreased life-time of the SCR catalysts. Therefore, the development of the urea deposition avoidance technologies is being treated as an important issue of the Urea-SCR systems. An experimental study was carried out to investigate the effects of the wall flow characteristics around the mixer-housing assembly with the variation of the mixer housing surrounding and supporting the mixer, which is designed to increase the wall flow and then to reduce droplet deposition. The flow characteristics was investigated by using a hot-wire anemometry for 2-D simplified duct model, and the housing tilt angles and the position of the mixer were changed : angle of $0^{\circ}$, $1^{\circ}$, $2^{\circ}$, $3^{\circ}$, and mixer positions of 0L, 0.5L, 1L. The results showed that the wall flow onto the exhaust pipe was improved with changing the tilt angle of the mixer housing, and the wall flow improved more when the position of the mixer was on 1L.

Air Fluid Analysis between Porous PE-Plate and Glass in Air-Floating FPD Conveyor System (공기부상 FPD 이송장치에서 다공질판과 글래스 사이의 공기유동 해석)

  • Lho, Tae-Jung;Shon, Tae-Young
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.9 no.4
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    • pp.878-885
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    • 2008
  • The FPDs(Flat Panel Displays) such as LCD(Liquid Crystal Display) and PDP(Plasma Display Panel) and OLED(Organic Light Emitting Diode), recently, have been substituted for CRT(Cathode Ray Tube) displays because they have a convex surface, small volume, light weight and lower electric power consumption. The productivity of FPDs is greatly dependent on the area of thin glass panel with 0.6 - 0.8mm thickness because FPDs are manufactured by cutting a large-scaled thin glass panel with patterns to the required product dimensions. So FPD's industries are trying to increase the area of thin glass panel. For example, the thin glass panel size of the 8th generation is 2,200mm in width, 2,600mm in length and 0.7mm in thickness. The air flows both in the thin glass panel and in the porous PE-plate surface were modeled and analyzed, from which a working condition was estimated. The thin glass panel on the porous PE-plate surface with self-lubricating characteristics was investigated and compared with that on the square duct floating bar surface with many holes of 1mm diameter when the thin glass panel contacts the floating bar surface due to malfunction of electric power supply.

A Study on Fatigue Characteristic of Stent Using Finite Element Analysis (나이티놀 와이어 스텐트의 피로도 특성에 대한 유한요소 해석)

  • Kim, Han-Ki;Shin, Il-Gyun;Kim, Dong-Gon;Kim, Seong-Hyeon;Lee, Ju-Ho;Ki, Byoyng-Yun;Suh, Tae-Suk;Kim, Sang-Ho
    • Progress in Medical Physics
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    • v.20 no.3
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    • pp.119-124
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    • 2009
  • Stents are frequently used throughout the human body. They keep pathways open in vascular or nonvascular duct for a long time. Therefore its stability is very important factor. In recent years, aconsiderable amount of research has been carried out in order to estimate mechanical properties of the stent such as expansion pressure behavior, radial recoil and longitudinal recoil using FEM (Finite element analyses). However, published works on simulation of stent fatigue behavior using FEM are relatively rare. In this paper, a nonlinear finite-element methodwas employed to analyses the compression of a stent using external pressure and fatigue behavior. Finite element analyses for the stent system were performed using NASTRAN FX. In conclusion this paper shows how the stent is behaved in the body, and its fatigue behavior.

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Analysis on Ventilation Efficiency of Standard Duck House using Computational Fluid Dynamics (전산유체역학을 이용한 표준 오리사 설계안에 대한 환기효율성 분석)

  • Yeo, Uk-Hyeon;Jo, Ye-Seul;Kwon, Kyeong-Seok;Ha, Tae-Hwan;Park, Se-Jun;Kim, Rack-Woo;Lee, Sang-Yeon;Lee, Seung-No;Lee, In-Bok;Seo, Il-Hwan
    • Journal of The Korean Society of Agricultural Engineers
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    • v.57 no.5
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    • pp.51-60
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    • 2015
  • In Korea, 69.4 % of duck farms had utilized conventional plastic greenhouses. In this facilities, there are difficulties in controlling indoor environments for raising duck. High rearing density in duct farms also made the environmental control difficult resulting in getting more stressed making their immune system weaker. Therefore, a facility is needed to having structurally enough solidity and high efficiency on the environmental control. So, new design plans of duck house have recently been conducted by National Institute of Animal Science in Korea. As a study in advance to establish standard, computational fluid dynamics (CFD) was used to estimate the aerodynamic problems according to the designs by means of overall and regional ventilation efficiencies quantitatively and qualitatively. Tracer gas decay (TGD) method was used to calculate ventilation rate according to the structural characteristics of duck houses including installation of indoor circulation fan. The results showed that natural ventilation rate was averagely 164 % higher than typically designed ventilation rate, 1 AER ($min^{-1}$). Meanwhile, mechanically ventilated duck houses made 81.2 % of summer ventilation rate requirement. Therefore, it is urgent to develop a new duck house considering more structural safety as well as higher efficiency of environmental control.

A Case of Successful Management of Sarcoidosis with Chylothorax Using Octreotide (옥트레오타이드를 이용한 유육종증과 동반된 유미흉의 보존적 치료 1예)

  • Jung, Kyung Soo;Moon, Ji Ae;Yoon, Sul hee;Byun, Min Kwang;Jung, Woo Young;Jung, Jae Hee;Choi, Sang Bong;Kim, Dae Joon;Pyo, Ju Yeon;Kim, Young Sam;Kim, Se Kyu;Chang, Joon;Kim, Sung Kyu;Park, Moo Suk
    • Tuberculosis and Respiratory Diseases
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    • v.62 no.2
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    • pp.119-124
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    • 2007
  • Sarcoidosis is a multi-system granulomatous disorder of an unknown etiology and affects individuals worldwide. It is characterized pathologically by the presence of non-caseating granulomas in more than one involved organ. However, pleural involvement of sarcoidosis is rare and there are no reported cases in Korea. Traditionally, sarcoidosis has often been treated with systemic corticosteroids or cytotoxic agents. In particular, chylothorax with sarcoidosis is usually treated with corticosteroid for approximately 3~6 months, followed by repeated therapeutic thoracentesis, talc pleurodesis, dietary treatment, or thoracic duct ligation where needed. We encountered a 46 years old female patient presenting with cough, dyspnea and both hilar lymphadenopathy (stage I) on chest radiograph. The patient was diagnosed with a non-caseating granuloma, sarcoidosis by a mediastinoscopic biopsy. For one month, she had suffered from dyspnea due to right side pleural effusion, which was clearly identified as a chylothorax on thoracentesis. Corticosteroid therapy with dietary adjustment was ineffective. She was treated successfully with a subcutaneous injection of octreotide for 3 weeks and oral corticosteroid. We report a case of successful and rapid treatment of chylothorax associated with sarcoidosis using octreotide and oral corticosteroid.