• 제목/요약/키워드: passenger flow

검색결과 212건 처리시간 0.022초

확대관 형상에 따른 DPF 내의 유동특성 해석 (Numerical study on the Air Flow Characteristics inside a DPF with Diffuser Shape)

  • 임동렬;이상업;김민정;김숭기;김성규
    • 유체기계공업학회:학술대회논문집
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    • 유체기계공업학회 2005년도 연구개발 발표회 논문집
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    • pp.796-802
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    • 2005
  • Numerical analysis has been conducted for improving air flow characteristics in the exhaust aftertreatment system of diesel-fueled passenger cars by changing axial length and cone shape of a DPF diffuser. The results of air velocity and static pressure distributions along with air flow uniformity results suggest that a diffuser shape with 2D or 3D function type is better for air flow patterns in front of a DPF.

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Dynamic PIV를 이용한 커튼형 에어백 부품림 장치의 유동해석 (Dynamic PIV analysis of High-Speed Flow Ejected from the Inflator Housing of a Curtain-type Airbag)

  • 장영길;김석;이상준
    • 유체기계공업학회:학술대회논문집
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    • 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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    • pp.407-408
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    • 2006
  • Passenger safety is one of the most important considerations in the purchase of an automobile. A curtain-type air bag is increasingly adapted in deluxe cars for protecting passengers from the danger of side clash. Inflator housing is a main part of the curtain-type air bag system for supplying high-pressure gases to pump up the air bag-curtain. Although the inflator housing is fundamental in designing a curtain-type air bag system, flow information on the inflator housing is very limited. In this study, we measured instantaneous velocity fields of a high-speed flow ejecting from the inflator housing using a dynamic PIV system. From the velocity field data measured at a high frame-rate, we evaluated the variation of the mass flow rate with time. From the instantaneous velocity fields of flow ejecting from the airbag inflator housing in the initial stage, we can see a flow pattern of broken shock wave front and its downward propagation. The flow ejecting from the inflator housing was found to have large velocity fluctuations and the maximum velocity was about 700m/s. The velocity of high-speed flow was decreased rapidly and the duration of high-speed flow over 400m/s was maintained only to 30ms. After 100ms, there was no perceptible flow.

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고속도로 공사구간에서의 차종별 승용차환산계수 (Passenger Car Equivalents of Various Vehicle Types on Expressway Work Zones)

  • 강승규
    • 대한교통학회지
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    • 제14권3호
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    • pp.61-73
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    • 1996
  • The objective of this paper is to estimate the PCE(Passenger Car Equivalents) of various vehicle types on expressway work zones. Headway samples of 5,359 vehicles were collected in 6 work zones in the Kyungbu Expressway between September and November of 1995. Average headways of 8 vehicle types based on the vehicle classification method of the Department of Construction and Transportation were calculated. A statistical test of effects of the types of the preceding vehicles were performed for the average headways between a vehicle type preceded by other vehicle types. The results show that the effects of the type of preceding vehicles are significant (exceeded 5% and 10% significance levels) and the PCEs of heavy vehicles on expressway work zones are higher than that of basic expressway section. Therefore, different adjustment factors should be applied for heavy vehicles in estimating saturation flow rates of expressway work zones. The study also derives an equation to determine PCEs of these vehicle types.

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승용 전조등 LED 램프의 방열판 자연 냉각특성 (Natural Cooling Characteristics of a Heat Sink for LED Headlight used in Passenger Cars)

  • 유재용;박설현
    • 한국기계가공학회지
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    • 제16권2호
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    • pp.142-148
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    • 2017
  • The objective of this study is to investigate the cooling characteristics of a heat sink for an LED headlight used in passenger cars. To this end, this study conducts the experimental and numerical analysis of the heat sink heated at constant heat fluxes without air flow applied. In the experiments, heat was transferred at a constant heat flux through the bottom of a heat sink. The measured temperature on pre-selected locations of the heat sink was in good agreement with the numerically predicted one. The experimental and numerical results indicate that the convective heat transfer coefficient for the natural convection mode was decreased by increasing the heat flux applied to the bottom of heat sink, lowering the cooling capabilities.

인천-영종 간 해상수송시스템 구축을 위한 경제적 타당성 분석 (A Feasibility Study on the Economic Aspect of Sea Transportation System between Inchon and Youngjong Island)

  • 전재우;이승희
    • 한국해양공학회지
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    • 제13권3B호
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    • pp.116-126
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    • 1999
  • The purpose of this study is to analyze the economic aspect of sea transportation system between Inchon and Youngjong island in which Inchon international airport is being constructed. Total demand of sea transportation arising from in the airport and Yongyu Muwi leisure complex was estimated. To select optimum transportation route, environmental conditions in and around Inchon harbour and Youngjong island including the change of water depth by tide current, fog, rain, wind adn typhoon, ets., were investigated. The preliminary consideration on ships (size, velocity, transport capacity, price), routes, operational modes, terminals and berthing facilities were carried out. The transportation cost per passenger by sea transportation system was estimated to compare with that of land transportation system. It was found that sea transportation system proposed is competitive to the transportation system.

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블레이드 형상변화에 따른 수중 추진기 방사 소음 예측에 관한 연구 (Numerical Prediction of Underwater Propeller Noise)

  • 설한신
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2006년도 춘계학술대회논문집
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    • pp.344-347
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    • 2006
  • Noise reduction and control is an important problem in the performance of underwater acoustic system and on the habitability of the passenger ship for crew and passenger. Furthermore, sound generated by a propeller is critical in underwater detection and is often related to the survivability of the vessel especially for military purpose. Generally propeller noise is often the dominant noise source of marine vehicle. The flow field is analyzed with potential-based panel method, and then the time dependent pressure and sheet cavity volume data are used as the input for Ffowcs Williams-Hawkings formulation to predict the far-field acoustics. Through this study, the dominant noise source of underwater propeller is analyzed, which will provide a basis for proper noise control strategies.

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운송 파급효과가 항공네트워크와 지역경제에 미치는 영향 (Transport Spillover Effect on Airport Networks and Its Impact on Regional Economy)

  • 왕흔신;라이폴린
    • 무역학회지
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    • 제47권4호
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    • pp.35-52
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    • 2022
  • Air transport is at the core of global economic growth. There is a close relationship between the flow of regional elements and the growth of the regional economy. It is easy to misestimate the impact of airports on the regional economy without considering spatial spillover effects. This study attempted to establish an asymmetric economic geographical weight matrix by applying the Spatial Durbin Model with cargo volume and passenger numbers as indicators. The influence of spillover effects on the regional economy, including direct spillover effects and indirect spillover effects are studied. The results revealed that passenger numbers and cargo volume have significant positive spillover effects on the regional economy. The driving effect of the airport on the regional economy was considered from a wider space scope. This study contributes to the scientific evaluation of the aviation economy.

3차원 유동해석을 통한 차량 배기소음 예측에 관한 연구 (Prediction of Vehicle Exhaust Noise using 3-Dimensional CFD Analysis)

  • 진봉용;이상호;조남효
    • 한국자동차공학회논문집
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    • 제9권5호
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    • pp.148-156
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    • 2001
  • Computational Fluid Dynamics (CFD) analysis was carried out to investigate exhaust gas flow and acoustic characteristics in the exhaust system of a passenger car. Transient 3-dimensional flow field in the front and rear mufflers was simulated by CFD and far-field sound pressure was modeled by a simple monopole source method. Engine performance simulation was also performed to obtain the boundary condition of instantaneous fluid flow variation at the inlet of the exhaust system. Detailed exhaust gas flow characteristics such as velocity and pressure distribution inside the mufflers were presented and the pulsating pressure amplitude was compared at several positions in the exhaust system to deduce sound pressure level. The present method of the acoustic analysis coupled with CFD techniques would be very effective for the prediction of sound noise from vehicle exhaust systems although the effects of the inlet boundary condition and heat transfer on the accuracy of the prediction have to be validated through further studies.

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차종별 교통류 모형을 이용한 편도 2차로 고속도로 공사구간 용량 산정 (Estimation of Capacity at Two-Lane Freeway Work Zone Using Traffic Flow Models of Each Vehicle-Type)

  • 박용진;김종식
    • 한국도로학회논문집
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    • 제13권3호
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    • pp.195-202
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    • 2011
  • 본 연구의 목적은 차종별 교통류 모형을 이용한 편도 2차로 고속도로 공사구간의 용량 값을 산정하는 것이다. 공사구간의 교통류 모형은 공사구간의 유입부 및 유출부를 대상으로 차종별 모형과 승용차 환산계수를 적용한 전체 차량에 대한 모형으로 도출하였다. 차종별 모형에서 산정된 최대교통류율은 승용차환산계수 및 중차량 비율을 적용하여 공사구간의 용량 값으로 전환하였다. 차종별 모형의 유입부 및 유출부 최대교통류율 값은 각각 1,845pcphpl과 1,884pcphpl로 산정되었으며 차량 전체를 대상으로 한 모형의 최대교통류율은 차종별 결과보다 높게 분석되었다. 모형의 비교 검증을 위하여 최대밀도에 따른 거리 차두간격을 적용하였다. 공사구간의 용량은 공사구간의 흐름이 안정된 유출부 용량보다 공사구간 진입을 위한 차선 변경 등으로 교통흐름이 원활하지 못한 유입부 용량에 좌우되므로 유입부 교통류 모형의 최대교통류율 값인 1,800pcphpl을 편도 2차로 고속도로 공사구간 용량 값으로 산정하였다.

차량 내부 탑승자의 쾌적성 평가를 위한 초기 냉방운전 성능에 대한 수치해석적 연구 (Numerical Analysis on the Initial Cool-down Performance Inside an Automobile for the Evaluation of Passenger's Thermal Comfort)

  • 김윤기;양장식;백제현;김경천;지호성
    • 한국자동차공학회논문집
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    • 제18권5호
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    • pp.115-123
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    • 2010
  • Cool-down performance after soaking is important because it affects passenger's thermal comfort. The cooling capacity of HVAC system determines initial cool down performance in most cases, the performance is also affected by location, and shape of panel vent, indoor seat arrangement. Therefore, optimal indoor designs are required in developing a new car. In this paper, initial cool down performance is predicted by CFD(computational fluid dynamics) analysis. Experimental time-averaging temperature data are used as inlet boundary condition. For more reliable analysis, real vehicle model and human FE model are used in grid generation procedure. Thermal and aerodynamic characteristics on re-circulation cool vent mode are investigated using CFX 12.0. Thermal comfort represented by PMV(predicted mean vote) is evaluated using acquired numerical data. Temperature and velocity fields show that flow in passenger's compartment after soaking is considerably unstable at the view point of thermodynamics. Volume-averaged temperature is decreased exponentially during overall cool down process. However, temperature monitored at different 16 spots in CFX-Solver shows local variation in head, chest, knee, foot. The cooling speed at the head and chest nearby panel vent are relatively faster than at the knee and foot. Horizontal temperature contour shows asymmetric distribution because of the location of exhaust vent. By evaluating the passenger's thermal comfort, slowest cooling region is found at the driver's seat.