• Title/Summary/Keyword: Air Tool

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Study on Combustion Performance and Burning Velocity in a Micro Combustor (초소형 연소기에서 연소성능과 연소속도에 대한 연구)

  • Na Hanbee;Lee Dae Hoon;Kwon Sejin
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.29 no.6 s.237
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    • pp.662-670
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    • 2005
  • The effect of heat loss on combustion performance and burning velocity of micro combustors in various conditions were exploited experimentally. Three different gases were used, and various geometric matrixes were considered to figure out the phenomena of combustion in a micro combustor. The micro combustors used in this study were constant volume combustors and had cylindrical shape. Geometric parameter of combustor was defined as combustor height and diameter. The effect of height was exploited parametrically as 1mm, 2mm and 3 mm and the effect of diameter was parameterized to be 7.5 mm and 15 mm. Three different combustibles which were Stoichiometric mixtures of methane and air, hydrogen and air, and mixture of hydrogen and air with fuel stoichiometry of two were used. By pressure measurement and visualization of flame propagation, characteristic of flame propagation was obtained. Flame propagations which were synchronized with pressure change within combustor were analyzed. From the analysis of images obtained during the flame propagations, burning velocity at each location of flame was obtained. About $7\%$ decrease in burning velocity of $CH_4/Air$ stoichiometric mixture compared with previous a empirical result was observed, and we can conclude that it is acceptable to use empirical equations for laminar premixed flame burning velocity to micro combustions. Results presented in this paper will give fine tool for analysis and prediction of combustion process within micro combustors.

A Study on Securing Ship Survivability focused on a Cost and Effectiveness Analysis for Air Defense Performance (대공방어성능에 대한 비용효과분석을 중심으로 한 함정생존성 확보방안 연구)

  • Choi, Sung-Lin;Park, Dong-Ki
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.5
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    • pp.2579-2586
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    • 2014
  • It is crucial to set up early the required performance of surface ship for preventing the risk factors such as an excess of performance, cost and period in development stage. In this study, MOP and MOE are proposed to establish the method for deriving alternatives, MOP represents the defensive effect for anti ship missiles and MOE is the ratio of cost and performance. The 16 engagement scenarios which selectively install RF decoy, RF jammer, CIWS and anti air missile are suggested. The simulation results by using NORAM tool operated by ROK Navy show that the ship survivability is 0.605~0.975 and MOP is 0.301~0.887. The analyzed results represent the operating scenario with RF decoy, RF jammer and short range anti air missile is the best cost and effectiveness measure.

A Simulation Study on the Performances of Revenue Management Models for an Air Cargo Network (시뮬레이션을 통한 항공화물 네트워크 수익관리 모형 성능 평가)

  • Lee, Kwang-Ryul;Yoon, Soo-Jeong;Lee, Chul-Ung
    • Journal of the Korea Society for Simulation
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    • v.18 no.1
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    • pp.41-51
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    • 2009
  • A discrete event simulation model is developed to evaluate the performances of three different revenue management methods for an air cargo network from Northeast China to North America and Europe. In the first method, a bid price model is applied only to the routes that pass through Incheon. In the second method, the bid price model is applied to all the routes. In third method, bid price and virtual nesting models are applied to the routes that pass through Incheon. The results show that the total revenue significantly increases with the employment of pricing and capacity control. The developed simulation model is a useful research tool to study marketing strategies for air cargo operations.

Experimental study on Thermal Comfort of Electric Vehicle Occupants Using Local Proximity Heating Module (국부 근접 난방 모듈을 이용한 전기차 탑승자의 열쾌적성에 대한 실험적 연구)

  • Chae-Yeol Lee;Jong-Han Im;Jae-Wook Lee;Sang-Hee Park
    • Journal of the Korean Society of Industry Convergence
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    • v.27 no.3
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    • pp.655-663
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    • 2024
  • In order to meet the technological demand for indoor heating systems that ensure winter thermal comfort during the transition from internal combustion engines to electrification, a localized proximity heating module using surface heating elements was developed. The operational performance of heating module was tested in the low temperature chamber. The experiment conditions were varied by changing the chamber temperature (-10, 0℃), the air flow rate (6.2, 6.0, 4.2m3/h), the heater power (100, 80, 60, 40W). Thermal comfort model was confirmed using the CBE Thermal Comfort Tool applying ASHRAE standard 55. Under -10℃ condition, thermal comfort was satisfied at 23.4, 23.2℃ at power of 100W and air flow rate 6.0, 4.6m3/h. Under 0℃ condition, at power of 80W, air flow rate 6.2, 6.0m3/h, and at power of 60W, air flow rate 4.6m3/h showed results of 25.7, 26.1, 23.0℃, respectively, satisfying thermal comfort. This study analyzed the operating performance of the local proximity heating module in the low temperature chamber and applied thermal comfort model to prove applicability of local proximity heating module using surface heating elements and how to utilize the thermal comfort model.

Effectiveness Assessment on the Soil Temperature of KMA as Ground Heat Source Using CFD in Pit Area (CFD를 이용한 기상청 지중온도의 피트부분 지중열원 유용성 평가에 관한 연구)

  • Min, Joon Ki;Kim, Jeong Tai
    • KIEAE Journal
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    • v.8 no.5
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    • pp.49-54
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    • 2008
  • The experimental of temperature, humidity and velocity was taken from the underground pit which utilized the system of ground heat source quite similar to the cool-pit system. Also, through CFD analysis, one could review the effectiveness of analysis of future alternatives. Furthermore, the temperature range of mock up cool-pit system was analyzed by inputting the weather data of annual average soil temperature provided by KMA(Korea Meteorological Administration) into the fluid simulation of anticipated heat distribution. Firstly, the difference between the temperature of air exhaust of the pit or the temperature of air supply of the compressor room and the experimental data for the month of May from the CFD analysis came out to be $0.6^{\circ}C$ and $0.9^{\circ}C$ respectively with tolerance of 3.1% and 4.7%. Secondly, the difference between the temperature of air exhaust of the Pit or the temperature of air supply of the compressor room and the experimental data for the month of July from the CFD analysis came out to be $0.8^{\circ}C$ and $1.1^{\circ}C$ respectively with tolerance of 3.3% and 4.5%. Thirdly, for the month of May, the difference between the experimental data taken for the air exhaust of the Pit or the air supply of the compressor room and soil temperature provided by KMA for monthly and yearly average temperature of Jeonju region came out be $1.9^{\circ}C$ and $1.8^{\circ}C$ respectively with tolerance of 10.7% and 9.8%. Fourthly, for the month of July, the difference between the experimental data taken for the air exhaust of the Pit or the air supply of the compressor room and soil temperature provided by KMA for monthly and yearly average temperature of Jeonju region came out be $1.1^{\circ}C$ and $1.4^{\circ}C$ respectively with tolerance of 4.5% and 5.8%. The result of above experiments allowed us to establish CFD model set up as a verification tool that is based on experimental data collected within the Pit area. Also, one could confirm the possibility to apply weather data of soil temperature provided by KMA in order to anticipate proper value for CFD analysis.

Spatial-temporal Assessment and Mapping of the Air Quality and Noise Pollution in a Sub-area Local Environment inside the Center of a Latin American Megacity: Universidad Nacional de Colombia - Bogotá Campus

  • Fredy Alejandro, Guevara Luna;Marco Andres, Guevara Luna;Nestor Yezid, Rojas Roa
    • Asian Journal of Atmospheric Environment
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    • v.12 no.3
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    • pp.232-243
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    • 2018
  • The construction, development and maintenance of an economically, environmentally and socially sustainable campus involves the integration of measuring tools and technical information that invites and encourages the community to know the actual state to generate positive actions for reducing the negative impacts over the local environment. At the Universidad Nacional de Colombia - Campus $Bogot{\acute{a}}$, a public area with daily traffic of more than 25000 people, the Environmental Management Bureau has committed with the monitoring of the noise pollution and air quality, as support to the campaigns aiming to reduce the pollutant emissions associated to the student's activities and campus operation. The target of this study is based in the implementation of mobile air quality and sonometry monitoring equipment, the mapping of the actual air quality and noise pollution inside the university campus as a novel methodology for a sub-area inside a megacity. This results and mapping are proposed as planning tool for the institution administrative sections. A mobile Kunak$^{(R)}$ Air & OPC air monitoring station with the capability to measure particulate matter $PM_{10}$, $PM_{2.5}$, Ozone ($O_3$), Sulfur Oxide ($SO_2$), Carbon Monoxide (CO) and Nitrogen Oxide ($NO_2$) as well as Temperature, Relative Humidity and Latitude and Longitude coordinates for the data georeferenciation; and a sonometer Cirrus$^{(R)}$ 162B Class 2 were used to perform the measurements. The measurements took place in conditions of academic activity and without it, with the aim of identify the impacts generated by the campus operation. Using the free code geographical information software QGIS$^{(R)}$ 2.18, the maps of each variable measured were developed, and the impacts generated by the operation of the campus were identified qualitative and quantitively. For the measured variables, an increase of around 21% for the $L_{Aeq}$ noise level and around 80% to 90% for air pollution were detected during the operation period.

Reliability Analysis of the GCM Data Downscaling Methods for the Climate-Induced Future Air Temperature Changes in the Coastal Zone (연안 해역의 미래 기온변화 예측을 위한 GCM 자료 Downscaling 기법의 신뢰수준 분석)

  • Lee, Khil-Ha;Cho, Hong-Yeon;Cho, Beom-Jun
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.20 no.1
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    • pp.34-41
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    • 2008
  • Future impact of anthropogenic climate-induced change on ecological regime has been an issue and information on water temperature is required for estimating coastal aquatic environment. One way to induce water temperature is to relate water temperature to air temperature and GCM is able to provide future air temperature data to do this. However, GCM data of low spatial resolution doesn't incorporate local or sitespecific air temperature in need of application, and downscaling processes are essential. In this study, a linear regression is used to relate nationally averaged air temperature to local area for the time period of 2000-2005. The RMSE for calibration (2000-2005) is 1.584, while the RMSE for validation is 1.675 for the year 2006 and 1.448 for the year 2007. The NSC for calibration (2000-2005) is 0.962, while the NSC for validation is 0.955 for the year 2006 and 0.963 for the year 2007. The results show that the linear regression is a good tool to relate local air temperature to nationally averaged air temperature with $1.0{\sim}2.0^{\circ}C$ of RMSE. The study will contribute to estimate future impact of climate-induced change on aquatic environment in Korean coastal zone.

Simulation-based Intake Manifold Runner Length Optimization for Improving Performance, Fuel Consumption and Emission of a Gasoline Engine (가솔린 엔진의 성능, 연비, 배출 가스를 동시에 고려한 시뮬레이션 기반 흡기 다기관 길이 최적화)

  • Kang, Yong-Hun;Choi, Dong-Hoon
    • Transactions of the Korean Society of Automotive Engineers
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    • v.18 no.5
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    • pp.62-67
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    • 2010
  • Exhausting fossil fuel and increasing concern of air pollution have brought on the change of the focus of developing new vehicles from performance to fuel economy and emission. The gasoline engines adopting the naturally aspirated way use the throttle-body for engine load control. Therefore, its pumping loss increases more than that of the diesel engine, and also mostly operating in a partial load condition has bad influence on fuel economy and emission. In these days, the continuous variable valve timing system and variable induction system are adopted in order to improve fuel consumption and emission. In this study, we optimize the runner length and operate region of variable induction system to simulataneously improve the performance, fuel economy, and emission of gasoline engine with employing GT-Power as a CAE tool for engine analysis and PIAnO as PIDO tool for process integration and design optimization.

A Study of the Experiment and the Calculation Method on the Coolant Flow Rate of Engine and Vehicle Cooling System (엔진 및 차량냉각계의 냉각수유량 측정실험 및 계산방법에 관한 연구)

  • 오창석;유택용;이은현;최재권
    • Transactions of the Korean Society of Automotive Engineers
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    • v.7 no.6
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    • pp.1-7
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    • 1999
  • In this study, the prediction method of coolant flow rates has been developed and applied to an engine and vehicle cooling system. The flow rate passing through each component of the system is very important parameter to evaluate the heat transfer process form the combustion gas to the coolant and the heat rejection process form the radiator /heater to the ambient air. However, the present study reveals that the measurement using the flowmeter fails to give practical flow rates due to its additive resistance. In contrast, the present method which uses the parallel and serial relationship of flow resistance proved to be a good tool to predict the real flow rates. It can be also used to design the cooling system in the incipient stage of engine/vehicle development . The procedure was coded to the computer program so as to use it flexibly and, in the future, to expand it into an independent design tool of the whole cooling system including the heat release and rejection.

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A Study On Heat Transfer and Flow Characteristics for Boring in Sewer by Rotating Cutter Tool (회전노즐장비 작동시 하수관내의 열전달 및 유동현상에 관한 연구)

  • Park Young-Ki;Lee Jang-Choon;Lee Dong-Joo
    • Journal of Environmental Science International
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    • v.15 no.1
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    • pp.95-100
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    • 2006
  • Heat transfer and flow characteristics in a pipe in which the rotating cutting tool for boring a underground pipe without digging were considered in this study. The amount of heat generation due to the friction between the rotating cutter and pipe wall, mixing (low of air and water injected to cool down are the two important factors to design the boring machine Computational fluid dynamics analysis using the Eulerian mixture model and the standard $\kappa-\varepsilon$ turbulence model was used to analyze the complex phenomena in a pipe during the process. Results show that pipe wall temperature decreased with increasing the cooling water inlet velocity. it is also shown that pipe wail temperature was lowered when the cutter rotation speed was increased until 600 rpm. There was no further cooling effect over 600 rpm.