• 제목/요약/키워드: 3-D combustion model

검색결과 93건 처리시간 0.029초

베어링 캡 유한 요소 해석 설계 방법 (Design Methodology of Main Bearing Cap by a Finite Element Analysis)

  • 양철호;한문식
    • 한국자동차공학회논문집
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    • 제17권1호
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    • pp.80-86
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    • 2009
  • Main bearing cap is one of the essential structural elements in internal combustion engine. Main bearing cap guides and holds the crankshaft, withstanding the full combustion and inertia loads of the engine. A seamless design methodology using FEA has been proposed to produce a reliable design of main bearing cap. A Levy's thick cylinder model was applied to calculate the contact pressure between bearing shell and housing bore. A calculated contact pressure at housing bore is within the allowed limit comparing with that from bearing shell model. An adequate FEA model was suggested to obtain reliable solutions for the durability of main bearing cap. 3D global model consists of engine bulkhead, main bearing cap, and bolts. Sub-model consisting of cap and part of bolts is used to get detailed solution of main bearing cap. A very careful contact modeling practice is needed to resolve the convergence problems frequently encountering during combined geometric and material non-linear problems. A proposed methodology has been applied to the main bearing cap model successfully and obtained reliable stress results and fatigue safety factors.

난류 Pilot 비예혼합 화염장의 상세구조 해석 (Numerical Investigations of Turbulent Piloted Non-Premixed Flames)

  • 이정원;전상태;김용모
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
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    • pp.185-186
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    • 2014
  • The multi-environment probability density function model has been applied to simulate the turbulent stratified premixed flames. The direct quadrature method of moments (DQMOM) has been adopted to solve the transport PDF equation due to its computational efficiency and robustness. The IEM mixing model is employed to represent the mixing process and the chemical mechanism is based on Gri 3.0 mechanism. Numerical results obtained in this study are precisely compared with experimental data in terms of unconditional and conditional means for scalar fields and velocity fields.

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미분탄 보일러의 연소용 공기공급 변화에 따른 노내 연소상태 해석 (Combustion Characteristics of Coal-Fired Boiler Depending on the Variations in Combustion Air Supply Method)

  • 서상일;박호영;강동수;정동해
    • 에너지공학
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    • 제19권3호
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    • pp.156-162
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    • 2010
  • 국내 미분탄 보일러의 로내 공기량 공급에 따른 연소특성 분석을 위한 3차원 전산해석 연구를 수행하였다. 보일러 연소해석 해석 결과의 건전성 검증을 위하여 보일러 출구, 즉 절탄기 후단에서의 가스 온도,$O_2$, NO, SOx 농도를 발전소의 실제 운전데이터와 비교하였다. 검증된 해석 결과를 기준조건으로 SOFA(Separated Over Fire Air)와 CCOFA(Closed Coupled Over Fire Air)에서의 연소 공기량을 변화시킨 경우 보일러내 NOx와 가스 온도 분포를 중심으로 각각의 경우를 비교하였다. 본 연구를 통하여 CCOFA보다는 SOFA 공기량의 변화에 따라 NOx 농도의 민감도가 더 큰 것을 알 수 있었으며 대류 전열부의 전열관군에서의 온도 분포가 다르게 나타나고 있어 가스온도 편차 방지를 위한 연소조정이 필요함을 알 수 있었다.

디젤 인젝터 분사율 예측을 위한 AMESim 기반 1-D 모델 구축 (1-D Model to Estimate Injection Rate for Diesel Injector using AMESim)

  • 이진우;김재헌;김기현;문석수;강진석;한상욱
    • 한국분무공학회지
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    • 제25권1호
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    • pp.8-14
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    • 2020
  • Recently, 1-D model-based engine development using virtual engine system is getting more attention than experimental-based engine development due to the advantages in time and cost. Injection rate profile is the one of the main parameters that determine the start and end of combustion. Therefore, it is essential to set up a sophisticated model to accurately predict the injection rate as starting point of virtual engine system. In this research, procedure of 1-D model setup based on AMESim is introduced to predict the dynamic behavior and injection rate of diesel injector. As a first step, detailed 3D cross-sectional drawing of the injector was achieved, which can be done with help of precision measurement system. Then an approximate AMESim model was provided based on the 3D drawing, which is composed of three part such as solenoid part, control chamber part and needle and nozzle orifice part. However, validation results in terms of total injection quantity showed some errors over the acceptable level. Therefore, experimental work including needle movement visualization, solenoid part analysis and flow characteristics of injector part was performed together to provide more accuracy of 1-D model. Finally, 1-D model with the accuracy of less than 10% of error compared with experimental result in terms of injection quantity and injection rate shape under normal temperature and single injection condition was established. Further work considering fuel temperature and multiple injection will be performed.

음향 경계 조건이 가스터빈 연소기에서의 연소불안정에 미치는 영향 (Effects of Acoustic Boundary Conditions on Combustion Instabilities in a Gas Turbine Combustor)

  • 임재영;김대식;김성구;차동진
    • 한국추진공학회지
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    • 제19권4호
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    • pp.15-23
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    • 2015
  • 본 연구는 유한요소해석 기반의 Helmholtz solver인 ASCI3D를 사용하여 예혼합 가스터빈 연소기에서 연소불안정 현상과 관련된 주요 결과들을 예측하였다. 해석결과는 실험결과와 비교할 때 일반적인 불안정 특성 예측에는 성공하였으나, 불안정 구간이 나타나는 영역을 다소 과대 예측하는 경향이 발견되었다. 이를 개선하기 위한 노력으로 반사계수가 불안정 특성에 미치는 영향이 분석되었다. 결과로부터 반사계수는 불안정 특성에 큰 영향을 미치고, 정확한 예측 결과를 얻기 위해서는 정확한 음향 경계 조건의 정의가 필수적인 것으로 나타났다.

LES와 Level-set Flamelet 기법을 이용한 가스터빈 환형 연소기용 스월 분사기의 난류 연소 특성 (Turbulent Combustion Characteristics of a Swirl Injector in a Gas Turbine Annular Combustor Using LES and Level-set Flamelet)

  • 김리나;홍지석;정원철;유광희;김종찬;성홍계
    • 한국추진공학회지
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    • 제18권2호
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    • pp.1-9
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    • 2014
  • 환형 연소기 내에서의 난류 연소 유동을 해석하고 유동 특성을 도출하기 위해 3차원 large-eddy simulation (LES)를 수행하였다. 연소실 내 복잡한 반응 연소 유동의 화염모사를 위해 level-set flamelet 기법을 적용하였다. 계산 모델로서 GEAE사의 LM6000 환형 싱글 연소기를 이용하였으며 작동 조건은 실험결과에 근거하였다. 연소실 내에서 난류 유동의 중요한 특징인 vortex breakdown과 스월분사기에서 분사되는 연소가스의 팽창으로 인한 중심 재순환 영역, 코너 재순환 영역 등을 관찰하였고, 난류화염 구조를 분석하였다.

순환유동층에서 유동매체량에 따른 수력학적 특성 연구 (Effect of Solid Mass Inventory on Hydrodynamics Characteristics in a Circulating Fluidized Bed)

  • 김은경;신동훈;이종민;김재성;황정호
    • 한국연소학회지
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    • 제7권4호
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    • pp.10-20
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    • 2002
  • This paper discusses effect of solid mass inventory on the hydrodynamic characteristics of circulating fluidized bed(CFB). Operating parameters of solid mass inventory and air flow rates were varied to understand their effects on fludization pattern. Experimental measurements were made in a CFB of which height and diameter are 3m and 0.05m respectively. Black SiC particles ranging from $100{\mu}m\;to\;500{\mu}m$ were employed as the bed material. Superficial gas velocity of riser and J-valve fluidizing velocity were in the ranges of $1.39{\sim}3.24m/s\;and\;0.139{\sim}0.232m/s$, respectively. The axial solid fraction and solid circulation rate of CFB were calculated based on the experimental data and compared with modellings through IEA-CFBC Model and commercial CFD code.

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고온·고압 조건에서 바이오디젤의 가연한계 예측 (A Prediction on the Flammability Limits of Biodiesel Fuel in the High Temperature and Pressure Conditions)

  • 임영찬;정준우;서현규
    • 한국분무공학회지
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    • 제24권4호
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    • pp.157-162
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    • 2019
  • This numerical study was analyzed to predict the flammability limits of biodiesel and diesel fuels in the high temperature and pressure conditions. To achieve this, the biodiesel fuel was simulated with the chemical species of n-heptane (n-C7H16), methyl decanoate (C11H22O2), and methyl-9-decenoate (C11H20O2), and the diesel fuel was substituted the chemical species of n-heptane. The closed 0-D homogeneous reactor model which was employed the 1100 K of ambient temperature and 35 atm of ambient pressure was used for the simulation of constant volume combustion, and the equivalence ratio was changed from 0.3 to 2.5 conditions. In addition, a comparative analysis study was conducted with the results of HCCI engine simulation and flammability limits according to the changes of equivalence ratio. The results of combustion temperature, pressure, and ignition delay were increased when the equivalence ratio elevated from 0.3 to 1.3 conditions because the increase in fuel oxidation rate affects the chemical reaction of the overall combustion process. Furthermore, the CO and NOX production under the rich combustion conditions are considered to have a trade off relationship since the OH radicals and O2 chemical species are greatly affected the CO and NOX production and oxidation processes.

Design Rules of Hybrid Stepping Machine for Free Piston Engine

  • Jeong, Sung-In
    • Journal of Electrical Engineering and Technology
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    • 제12권3호
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    • pp.1219-1226
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    • 2017
  • This paper presents the hybrid stepping machine for linear oscillating generators. The focus of the work is the suggestion of the improved model through the comparison of proposed models ; new flux concentrating PMs mover of the hybrid stepping generator is proposed based on the symmetrical and non-symmetrical stator cores of the surface mounted PMs mover, and non-slanted PMs and slanted PMs of the flux concentrating PMs mover. It is achieved using equivalent magnetic circuit considering leakage elements. Finally, this study suggests new hybrid stepping structure of linear oscillating generator.

스월 환형연소기의 반응 및 비반응 유동 특성 연구를 위한 3차원 Large Eddy Simulation (3-D LES for Reacting and Non-reacting Flow Characteristics on a Swirl Stabilized Annular Combustor)

  • 김종찬;성홍계;차봉준
    • 한국추진공학회:학술대회논문집
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    • 한국추진공학회 2008년도 제31회 추계학술대회논문집
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    • pp.449-452
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    • 2008
  • 환형 스월 난류 연소기 내에서 반응, 비반응시 발생하는 유동의 차이를 flamelet 난류연소와 난류유동 모델을 모두 고려한 3차원 LES 기법으로 연구하였다. 계산 모델은 GEAE의 LM6000 환형연소기를 이용하였으며, 조건은 실험에서 얻어진 값을 이용하였다. 연소시 열방출에 의해 연소가스의 체적이 팽창하고 이로 인해 유입되는 스월의 주흐름은 하류방향으로 더욱 뻗어나간다. 비반응에서 나타났던 수직 단면에서의 타원형의 속도 분포는 원형에 가깝게 변하며, 비반응 유동장에서는 와류의 분포가 광범위하게 나타나지만, 반응유동에서는 약한 와류들은 소멸되는 것으로 나타났다. 즉 반응과 비반응에서 와류 분포와 강도, 그리고 동일 세기의 와류의 크기가 확연히 다르게 나타나는데, 이는 연소에 의한 밀도 팽창에 의한 영향으로 판단된다.

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