• Title/Summary/Keyword: 3-D combustion model

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

  • Yang, Chull-Ho;Han, Moon-Sik
    • Transactions of the Korean Society of Automotive Engineers
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    • v.17 no.1
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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.

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

  • Lee, Jeonwon;Jeon, Sangtae;Kim, Yongmo
    • 한국연소학회:학술대회논문집
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    • 2014.11a
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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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Combustion Characteristics of Coal-Fired Boiler Depending on the Variations in Combustion Air Supply Method (미분탄 보일러의 연소용 공기공급 변화에 따른 노내 연소상태 해석)

  • Seo, San-Il;Park, Ho-Young;Kang, Dong-Soo;Jeong, Dong-Hae
    • Journal of Energy Engineering
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    • v.19 no.3
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    • pp.156-162
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    • 2010
  • 3-D CFD(Computational Fluid Dynamics) work were carried out to investigate the combustion characteristics in a boiler depending on the variations in air supply condition. For the gas temperature, $O_2$, NO, SOx at the outlet of economizer, the predicted values were been compared with the measured data. With the verified CFD model, the effects of air flow rates through SOFA(Separated Over Fire Air) and CCOFA(Closed Coupled Over Fire Air) on the combustion behavior in a boiler were simulated, and the distributions of NOx and gas temperature were mainly compared each other. The change in SOFA air flow rate gave the more sensitive effect on NOx than that in CCOFA. The distributions of gas temperature at convection path are differed with the changes in SOFA and CCOFA flow rate, so the combustion modification such as yaw anlge adjustment are required to get an enhanced gas temperature distribution.

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

  • Lee, Jinwoo;Kim, Jaeheun;Kim, Kihyun;Moon, Seoksu;Kang, Jinsuk;Han, Sangwook
    • Journal of ILASS-Korea
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    • v.25 no.1
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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.

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

  • Lim, Jaeyoung;Kim, Deasik;Kim, Seong-Ku;Cha, Dong Jin
    • Journal of the Korean Society of Propulsion Engineers
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    • v.19 no.4
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    • pp.15-23
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    • 2015
  • This study predicts the basic characteristics of combustion instabilities in a gas turbine lean premixed combustor using ASCI3D code which is a FEM(Finite Element Method)-based Helmholtz solver. The prediction results show the good agreement with the measured data in modeling the overall combustion instability features, however, the code is found to overpredict the unstable conditions. As one of the efforts to improve the model accuracy, the effects of acoustic boundary conditions on the instability growth rate are analyzed. As a result, it is shown that the acoustic reflection coefficient has a great impact on the instability and the prediction accuracy can be enhanced by defining the precise acoustic conditions.

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

  • Kim, Lina;Hong, Ji-Seok;Jeong, Won Cheol;Yoo, Kwang-Hee;Kim, Jong-Chan;Sung, Hong-Gye
    • Journal of the Korean Society of Propulsion Engineers
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    • v.18 no.2
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    • pp.1-9
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    • 2014
  • To investigate the flame dynamics in an annular combustor with single swirl injector, a 3D large-eddy simulation (LES) and a level-set flamelet turbulent combustion model have been implemented. The LM6000 developed by GEAE has been used as the combustor of concern and boundary conditions are based on experimental data. The strong central toroidal recirculation zone induced by the volume expansion of the combustion gas and the vortex breakdown continuously occurred through the procession of the vortex with decreasing strength, are observed.

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

  • Kim, E.K.;Shin, D.;Lee, J.;Kim, J.;Hwang, J.
    • Journal of the Korean Society of Combustion
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    • v.7 no.4
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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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A Prediction on the Flammability Limits of Biodiesel Fuel in the High Temperature and Pressure Conditions (고온·고압 조건에서 바이오디젤의 가연한계 예측)

  • Lim, Young Chan;Jung, Jun Woo;Suh, Hyun Kyu
    • Journal of ILASS-Korea
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    • v.24 no.4
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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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    • v.12 no.3
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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.

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

  • Kim, Jong-Chan;Sung, Hong-Gye;Cha, Bong-Jun
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2008.11a
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    • pp.449-452
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    • 2008
  • Flow difference between reacting and non-reacting case in a swirl stabilized annular combustor is investigated using 3D Large Eddy Simulation with flamelet turbulent combustion model. The combustor of concern is the LM6000, lean premixed dry low-NOx annular combustor, developed by GEAE. Boundary conditions are based on experimental data. Heat release as a result of combustion put the dilatation of density in primary combustion zone highly increased so that the main swirl stream behind of a swirl cup stretched further downstream than that of non-reacting case. The oval shape of core flow in cross-section to flow direction, which clearly observed in non-reacting case, tends to be circle, and small vorticities in wide range in non-reacting case disappears, but the size of iso-vorticity increase in reacting case.

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