电控喷油器内部流场及喷雾场数值仿真研究

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3.0 侯斌 2024-11-19 4 4 3.19MB 55 页 15积分
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摘 要
改善发动机燃烧、降低排放的关键是合理控制进气、供油及混合气形成，改
善缸内工质的形成质量。电控喷油器的作用是精确地计量燃油并形成喷雾，与空
气混合形成浓度合适的混合气，以满足发动机不同工况的需要。电控喷油器内部
燃油流动特性及喷雾雾化质量是影响汽油机缸内混合气品质的关键因素，也是当
前电控喷油器研究的热点和难点。由于电控喷油器的喷射过程涉及内部电磁场、
燃油的内部流动以及喷雾雾化等过程，客观上要求将上述过程深入研究，从总体
上把握电控喷油器的内在机理，以加快国产电控喷油器自主研发进程。近年来国
内的很多高校和研究所，从不同角度对电控喷油器进行了深入的研究与探索。流
体力学的理论发展及计算流体力学（CFD）软件的发展，为深入研究喷油器内部燃
料流动机理及喷雾雾化性能提供了便利。
本文以电控喷油器为对象，建立了三维模型，利用 CFD 仿真软件对电控喷油
器的流场区域进行了网格划分。针对不同结构和环境参数对内部流场的压力与速
度分布进行了仿真计算，经对比分析得出电控喷油器内部燃油流动的规律。之后，
建立喷雾场区域，以内部流场的出口参数作为喷雾场仿真计算的边界条件，对电
控喷油器的喷雾过程进行了数值模拟计算，得到喷雾的贯穿距离和喷雾锥角等喷
雾几何结构以及燃油雾化的颗粒大小和颗粒分布等物理参数。
本文所见模型正确，采取的算法合理，通过模拟计算真实再现了电控喷油器
内部燃油的流动形态及外部喷雾场的喷射特征。这种研究的优点是可以缩短产品
开发周期，降低研究成本，并克服了实际试验时难以观察到微小、快速变化现象
的缺点，对电控喷油器的研制及结构优化设计具有指导意义。
关键词：电控喷油器 内部流场 喷雾场 CFD 数值仿真
ABSTRACT
The key of improving the engine combustion and reducing the emission is to
reasonably control air inflow, fuel supply and the mixture formation, which can improve
the quality of mixture in cylinder. The function of electronic injector is to precisely
measure the fuel and form the fuel spray, so that the fuel together with air can be formed
into the mixture gas with appropriate concentration to meet the need of the engine’s
different work conditions. The inner flow characteristics of the electronic injector and
the fuel spray atomization quality as the key factors affect the quality of the mixture in
cylinder, which are also the hot spots and difficulties in current study on electronic
injector. As the electronic injector’s injection process involves internal electromagnetic
field, inner fuel flow, spray atomization and other processes. Objectively, it requires
further study above, and grasping the internal mechanism of electronic injector as a
whole, so as to accelerate the domestic electric injector independent research and
development process. For the past few years, many domestic universities and research
institutes made deeply investigation and exploratory research from different aspects on
the electronic injector. The development of the hydro-mechanical theory and
computational fluid dynamics (CFD) software facilitate the in-depth study on the fuel
flow mechanism inside of the electronic injector and the performance of the spray
atomization.
The paper established a three-dimensional model, in which electronic injector is to
see as the object. Mesh the model by using CFD simulation software. The pressure and
velocity distributions in the flow field were simulated for different structural and
environment parameters. Comparing the results, the law of the fuel flow in electronic
injector was obtained. Then, the spray field area was established to simulate the spray
field of the Electronic Fuel Injector. These boundary conditions of this spray model are
gained from the flow export parameters. From the simulation, the paper drew the
conclusions about the spray geometry including spray penetration and cone angle, as
well as the size of fuel atomization particles, the distribution of particles and other
physical parameters.
The model of the paper is correct and the taken algorithm is reasonable. The
simulations realistically reproduced the inner flow’s pattern and the spray features of
electronic injector. The advantages of the study are shorting the product development
cycle, reducing the research costs and overcoming the shortcomings of the small,
rapidly phenomenon which is difficult to observe in practical test, as well as the results
are useful for the optimum design of the nozzle structure.
Key Words: Electronic injector ，inner flow ，spray field ，CFD,
numerical simulation
目 录
中文摘要
ABSTRACT
第一章 绪 论 ...................................................................................................................1
§1.1 引言 ...................................................................................................................1
§1.2 电控喷油器的发展 ...........................................................................................1
§1.3 电控喷油器的国内外研究现状 .......................................................................2
§1.3.1 国外电控喷油器的研究现状 .................................................................2
§1.3.2 国内电控喷油器的研究现状 .................................................................3
§1.4 电控喷油器的研究意义 ...................................................................................3
§1.5 课题来源和本文的主要研究内容 ...................................................................4
§1.5.1 课题来源 .................................................................................................4
§1.5.2 本文的主要研究内容 .............................................................................5
第二章 计算流体动力学的相关理论 .............................................................................6
§2.1 计算流体动力学概述 .......................................................................................6
§2.1.1 计算流体动力学的定义 .........................................................................6
§2.1.2 计算流体动力学的特点 .........................................................................6
§2.1.3 计算流体动力学的工作步骤 .................................................................7
§2.1.4 计算流体动力学的应用领域 .................................................................7
§2.1.5 计算流体动力学在离散方式上的分类 .................................................7
§2.2 流体与流动的基本特性 ...................................................................................8
§2.2.1 理想流体与粘性流体 .............................................................................8
§2.2.2 牛顿流体与非牛顿流体 .........................................................................9
§2.2.3 流体热传导及扩散 .................................................................................9
§2.2.4 可压流体与不可压流体 .........................................................................9
§2.2.5 定常与非定常流动 ................................................................................10
§2.2.6 层流与湍流 ...........................................................................................10
§2.3 流体动力学控制方程 .....................................................................................10
§2.3.1 质量守恒方程 .......................................................................................11
§2.3.2 动量守恒方程 .......................................................................................11
§2.3.3 能量守恒方程 .......................................................................................12
§2.3.4 湍流输运方程 .......................................................................................12
§ 2.4 喷雾场的结构 ................................................................................................13
§ 2.4.1 喷雾场的分区 ......................................................................................13
§ 2.4.2 喷雾的近场特性 ..................................................................................14
§ 2.5 油气两相模型 ................................................................................................15
§ 2.5.1 连续液滴模型（CDM）.................................................................... 15
§ 2.5.2 离散液滴模型（DDM）.................................................................... 15
§2.6 CFD 的求解过程 .............................................................................................18
§2.7 FLUENT 及AVL FIRE 软件简介 .................................................................. 19
§ 2.7.1 FLUENT 软件简介 .............................................................................. 19
§ 2.7.2 AVL FIRE 软件简介 .............................................................................20
§2.8 本章小结 .........................................................................................................20
第三章 电控喷油器模型构建 .......................................................................................21
§3.1 电控喷油器的结构简介 .................................................................................21
§3.2 电控喷油器的仿真模型 .................................................................................22
§3.3 建立对比模型 .................................................................................................23
§3.3.1 升程不同的模型 ...................................................................................23
§3.3.2 喷孔倾斜角不同的模型 .......................................................................23
§3.3.3 喷孔大小不同的模型 ...........................................................................24
§3.3.4 进口压力不同的模型 ...........................................................................25
§3.4 划分网格及确定边界条件 .............................................................................25
§3.4.1 划分网格 ...............................................................................................25
§3.4.2 对几何模型进行网格划分 ...................................................................28
§3.4.3 确定边界条件 .......................................................................................28
§3.5 本章小结 ..........................................................................................................28
第四章 电控喷油器内部流场仿真计算及结果分析 ...................................................29
§4.1 不同球阀升程下的内部流场分析 .................................................................29
§4.1.1 压力云图分析 .......................................................................................29
§4.1.2 速度矢量图分析 ...................................................................................31
§4.2 不同喷孔倾斜角下的内部流场分析 .............................................................32
§4.2.1 压力云图分析 .......................................................................................32
§4.2.2 速度矢量图分析 ...................................................................................33
§4.3 不同喷孔直径下的内部流场分析 .................................................................34
§4.3.1 压力云图分析 .......................................................................................34
§4.3.2 速度矢量图分析 ...................................................................................35
§4.4 不同进口压力下的内部流场分析 ..................................................................37
§4.4.1 压力云图分析 .......................................................................................37
§4.4.2 速度矢量图分析 ...................................................................................38
§4.5 本章小结 .........................................................................................................39
第五章 电控喷油器喷雾场仿真计算及结果分析 .......................................................40
§5.1 喷雾场的建立 ..................................................................................................40
§5.2 仿真结果分析 .................................................................................................40
§5.2.1 相同压力下的喷雾场 ...........................................................................40
§5.2.2 不同压力下的喷雾场 ...........................................................................44
§5.3 本章小结 .........................................................................................................45
第六章 总结与展望 .......................................................................................................46
§6.1 总结 .................................................................................................................46
§6.2 展望 .................................................................................................................46
参考文献 .........................................................................................................................47
在读期间公开发表的论文和承担科研项目及取得成果 .............................................50
致 谢 .............................................................................................................................51
摘要：

摘要改善发动机燃烧、降低排放的关键是合理控制进气、供油及混合气形成，改善缸内工质的形成质量。电控喷油器的作用是精确地计量燃油并形成喷雾，与空气混合形成浓度合适的混合气，以满足发动机不同工况的需要。电控喷油器内部燃油流动特性及喷雾雾化质量是影响汽油机缸内混合气品质的关键因素，也是当前电控喷油器研究的热点和难点。由于电控喷油器的喷射过程涉及内部电磁场、燃油的内部流动以及喷雾雾化等过程，客观上要求将上述过程深入研究，从总体上把握电控喷油器的内在机理，以加快国产电控喷油器自主研发进程。近年来国内的很多高校和研究所，从不同角度对电控喷油器进行了深入的研究与探索。流体力学的理论发展及计算流体力学（CFD）...

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作者：侯斌 分类：高等教育资料 价格：15积分 属性：55 页 大小：3.19MB 格式：PDF 时间：2024-11-19

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