摘 要

随着内燃机的发展，其内部工作要求也逐渐提高，部件工作温度随之升高。为满足更高的工作要求，将热障涂层应用于内燃机活塞，其顶部涂层的隔热性，能够使燃烧室温度提高。其中陶瓷层主要起隔热作用，粘结层则更有利于涂层与活塞基体的结合。为研究热障涂层对活塞基体的影响，本文做了如下工作：

(1)建立了热障涂层活塞传热模型，并使用Soildworks建模软件，建立带有陶瓷层与粘结层的热障涂层活塞几何模型。将模型导入ANSYS workbench划分网格，根据经验公式，计算得到活塞的热边界条件。

(2)使用ANSYS workbench软件，输入活塞各部分材料性能参数，以及热边界条件等，对热障涂层活塞工作过程中的稳态温度场等进行仿真模拟，得到热障涂层活塞的稳态温度场、热流量、热应力与热变形云图，并与普通活塞仿真结果进行比较。

(3)使用Origin软件，利用导出的路径数据，对在热障涂层与普通活塞顶部定义的路径进行分析，绘制与径向距离相关的温度、热应力与热变形曲线，分析比较两者的结果。

分析结果表明，热障涂层的作用主要在于显著降低活塞基体温度，同时又能够提高燃烧室温度，可满足内燃机更高的工作温度要求，并保护活塞。与普通活塞相比，热障涂层活塞有更高的燃烧室温度，内部陶瓷层与粘结层交界处有较大的热应力，整体上有较小的热变形。本文主要分析了热障涂层的热负荷与使用可靠性，在对结果进行分析的基础上，可对热障涂层的设计加以改进。

关键词：热障涂层；活塞；三维建模；热分析；数值仿真

Abstract

The working requirements in engines have gradually increased with the progress in the internal combustion engine, so the working temperature of the components in engines has increased. In order to meet higher working requirements, the thermal barrier coating is applied to the piston of the internal combustion engine. The thermal insulation of the top coating can increase the temperature of the combustion chamber. Among them, the ceramic layer mainly plays the role of heat insulation, and the bonding layer is more conducive to the combination of the coating and the piston base. In order to study the influence of the thermal barrier coating on the piston substrate, this paper including the following work:

(1) The heat transfer model of the thermal barrier coating piston was built. Using Soildsworks, I set up the geometric model of the piston with ceramic layer and bonding layer. The model is imported into ANSYS workbench to mesh, and the thermal boundary conditions of the piston are calculated according to the empirical formula.

(2) Using ANSYS workbench, input the material performance parameters of each part of the piston, as well as thermal boundary conditions, etc., to simulate the steady-state temperature field during the operation of the thermal barrier coating piston to obtain the steady-state temperature, heat flow, thermal stress and thermal deformation clouds of the thermal barrier coating piston. These simulation results are compared and analyzed with those of ordinary pistons.

(3) Use Origin to analyze the path defined on the top of the thermal barrier coating and the ordinary piston, use the exported path data, draw the temperature, thermal stress and thermal deformation curves related to the radial distance, analyze and compare the two result.

The analysis results show that the thermal barrier coating mainly significantly lower the temperature of the piston substrate, while at the same time can increase the temperature of the combustion chamber, which can meet the higher operating temperature requirements of internal combustion engines and protect the piston. Compared with ordinary pistons, thermal barrier coated pistons have a higher combustion chamber temperature, a larger thermal stress at the interface between the inner ceramic layer and the bonding layer, and a smaller thermal deformation on the whole. This paper mainly analyzes the heat load and stability of thermal barrier coatings. In view of the analysis of the results, we can make the design of thermal barrier coatings better.

Key Words: thermal barrier coating; piston; three-dimensional modeling; thermal analysis; numerical simulation

目 录

第一章 引言 1

1.1研究背景及意义 1

1.2国内外研究现状 1

1.2.1国内研究现状 1

1.2.2国外研究现状 2

1.3本论文主要内容与研究目的 3

1.3.1主要内容 4

1.3.2研究目的 4

第二章 基础理论 5

2.1热能传递基本方式 5

2.1.1热传导 5

2.1.2热对流 5

2.1.3热辐射 5

2.2轴对称稳定温度场微分方程 5

2.3热边界条件 6

2.3.1第一类边界条件 6

2.3.2第二类边界条件 6

2.3.3第三类边界条件 6

2.4活塞热边界条件的确定 6

2.5活塞热应力分析方程 7

第三章 活塞数值仿真 9

3.1活塞数学模型 9

3.2活塞几何模型 9

3.3活塞模型网格划分 10

3.4活塞热边界条件 11

第四章 结果与分析 12

4.1活塞整体热分析 12

4.1.1热障涂层活塞热分析 12

4.1.2热障涂层活塞与普通活塞的对比分析 14

4.2活塞顶部路径分析 16

第五章 结论与展望 20

5.1结论 20

5.2展望 20

参考文献 21

致 谢 23

第一章 引言

1.1研究背景及意义

近年来，内燃机的发展有提高功率等方向。内燃机功率提高的同时，工作温度要求逐渐提高，在内燃机工作过程中，受热零部件运转温度随工作温度提高。活塞作为内燃机核心部件，承受了较大的热负荷，容易由于高温产生损坏现象。