【作者】 谭建松；

【导师】 俞小莉；

【作者基本信息】 浙江大学 ， 动力机械及工程， 2005， 博士

【摘要】 活塞作为发动机的主要受热零件之一，在实际应用中，承受着剧烈的高周及低周热冲击作用，这是活塞热损伤的主要原因所在。本文在理论研究方面并没有建立更为复杂的模型，而是通过集总参数、一维平壁、二维轴对称三种不同模型对150活塞进行了仿真对比研究。研究工作的侧重点在试验上，主要进行了发动机多通道储测系统的研制，并利用该系统对150活塞实际工况下温度及应力进行了测量；同时在国内首次建立了基于激光加热的热冲击模拟试验台架，并创新性地将激光光束变换技术应用于活塞热冲击模拟试验。上述试验技术的开发为深入探索内燃机活塞等受热零部件热状态变化规律提供了先进的手段，进而为工程实际中热损伤现象的预防奠定了工作基础。 本文的主要工作及结论如下： 1)文中在给出活塞的集总参数模型、一维平壁模型、二维有限元模型的基础上，着重分析了考虑动态耦合效应的一维平壁模型。分析结果表明：一维平壁模型中惯性项与准静态计算结果差别甚微，可以忽略不计。同时通过计算可知，考虑耦合项的导热模型与傅立叶导热方程相比，仅是引进了一个常数项，两方程计算结果相差仅1.8％。通过对惯性项及耦合项的上述处理并以矩形波载荷为激励，得到了一维平壁模型的解析解。并从材料物性参数，载荷强度，载荷周期以及初始温度等方面研究了各参数对一维平壁模型仿真计算结果的影响，结果显示：在上述因素中，载荷强度对仿真结果的影响最为显著。 2)以150活塞为例，分别应用集总参数模型、一维平壁模型、二维轴对称有限元模型进行仿真对比研究。计算结果表明：三种模型都能够对活塞的高周热冲击过程进行模拟，活塞温度波动趋势相同，波动幅值存在差别。对于高周热冲击过程中的应力仿真，集总参数模型由于建立在忽略内部温度变化的基础上，因而不适用；一维平壁模型、二维轴对称模型的仿真结果与实际情况存在较大偏差，这是因为模型的计算精度与边界条件以及初始条件的选取有直接关系。因此，在活塞热冲击的研究上，理论模型的复杂程度并不是主要因素，边界条件和初始条件的选择是否合适才是模型是否实用的先决条件，而边界条件与初始条件的选择在很大程度上上依赖于试验。 3)研制了多通道活塞储测仪，该仪器可以安装于活塞底部，对活塞在实际运行过程中的温度、应力参数进行在线测量及存储，停机后再对储测仪内存储的试验数据进行处理。在150活塞上的实际应用表明，该系统的更多还原

【Abstract】 High-frequency and low-frequency thermal shock under different conditions, these are the main factors that lead to the thermal damage of piston. In this paper, high-frequency thermal shock of piston was studied by means of experimental way. The main research work was not focused on the theoretic way. So the new and complicated models were not developed. The main work in theoretic way was the analysis of the simulated results by means of the lumped parameter, 1 dimension plane wall and 2 dimension finite element models.In this paper, a multi-channel stored testing and measuring system (MSTMS) was established, the temperature and strain values under real operating conditions are also measured by this equipment. A laser heat thermal shock test bench was developed for the first time in China, and also the laser light beam space transform technology was used in the piston thermal shock experiment innovatively. These research works make steady base for the study of the thermal damage of the piston. The main content and conclusion in this paper were shown as following:1. In theoretic way, there are three different models: the lumped parameter model, 1 dimension plane wall model and 2 dimension model used for temperature and strain analyses of the piston. The influence of coupling factor and inertia factor in 1 dimension plane wall was also analyzed. The studies show that the simulated result of 1 dimension plane wall model with inertia factor is good agreement with the simulated result of quasi-stationary 1 dimension plane model. And the error between the classic Fourier heat conduction equation and the equation with the influence of coupling is only 1.8%. The affection of the material characteristic, load intensity, load cycle, initial temperature on the simulation results under the rectangle thermal shock model is also studied. The results shown that the load intensity is one of the most important among the parameters.2. Based on the above theory preparation, the 150 piston’s dynamic thermal behavior under high-frequency thermal shock is simulated by using the three models. The simulated results show that the three models can simulate the piston’s temperature variation quite well, but simulated results of the thermal stress are not agreement with the test data that gotten under the engine’s operating conditions. This is due to the boundary constraint and the initial temperature of these models not agreement with the engine’s operating condition. In conclusion, the boundary更多还原