【作者】 张宏帅；

【导师】 梁桂华；

【作者基本信息】 大连理工大学 ， 船舶与海洋结构物设计制造， 2006， 硕士

【摘要】 内燃机经过一百多年的发展,在应用范围十分广泛。随着能源、环境问题的日益突出,当今世界各国对内燃机的动力性、经济性、环保性提出了越来越高的要求。内燃机缸内流场是影响缸内油气混合质量和燃烧优劣的重要因素,多年以来,为了形成有利于油气均匀混合的流场,研究者们对燃烧室和进气道的几何形状和尺寸、位置等进行了各种各样的分析和改进。本课题试图从一个崭新的角度出发,利用射流与挡板相互作用形成反射流的原理,在2135柴油机的缸套上部逆着进气流的方向做一折壁。并且利用Star-CD对这种几何形状的缸内流场进行数值模拟,同时在柴油机上进行实验,用PIV测试技术对其缸内流场进行测试和分析。通过实验与模拟计算相结合的方法,探讨折壁处产生的反射流作用对缸内形成微涡流场的影响规律,为进一步全面分析内燃机结构参数对整机性能的影响提供有益的借鉴。本文主要工作如下: 1.使用UG软件建立气道-气缸-燃烧室一体的计算模型,然后用Pro-surf和Pro-am对数字模型进行修改和网格划分。并用Star-CD进行了缸内流场的模拟计算。 因为Star-CD默认的气缸为圆柱形,而本文研究的气缸带有内凹结构,所以不能直接应用Star-CD计算,经过对其中个别程序文件的修改和特殊边界条件设置后,在LINUX环境下运行成功,计算出了得到气缸指定位置纵(横)剖面位置在不同曲轴转角下的速度分布。 2.应用PIV测试设备在2135柴油缸机上试验,取得在活塞上止点附近,两种气缸在指定横剖面位置在不同曲轴转角下的速度场分布。 3.将带视窗和不带视窗的两种进气系统在相同剖面、相同曲轴转角的模拟速度场进行对比分析;同时,对此两种进气系统的相同剖面位置在不同曲轴转角下PIV实验得到的速度场进行对比,从两个方面理论与实验对比的角度来研究带内凹挡板结构的气缸对缸内微涡流场的影响。更多还原

【Abstract】 After one hundreds years of development, the internal combustion engine has been widely used in every walk of life. With the increasing concern about the energy sources and environment issues, many countries put up more and more requirement for the power 、 the economic and the environmental of the IC engine. The airflow field in cylinder plays a key role to the air-oil mixing quality and the combustion performance. To get a more perfect airflow field, for years, many researchers have been done a great deal of analyses and betterment about the geometry shape、 the dimensions and the its locations of the combustion room and intake duct.This paper researches the airflow field from a different point of view. Based the reflection effect theory between the intake air flow and the baffle in the cylinder wall, a concave structure embedded in the cylinder is made with its direction against the intake air flow. Then a simulation of the airflow field in the cylinder is done. At the same time, a PIV test is carried out. At the last, by the contrast and analyses between the results of the simulation and test, the reflection effect of the baffle is investigated. This provides more details to the further research of the micro eddy flow formation. The study will do useful reference to a thorough study of the infections between the configuration parameters and the performance. The main work is as follow:At the first, a digital combination geometry model of the intake duct—cylinder—combustion room is established. Then the soft wares of Pro-surf and Pro-am are used to do some work of repair and mesh generation. At last, the airflow motion and distribution rules are simulated with the Star-CD.As a special structure, it cannot be simulated directly by Star-CD. Though the program rework and the special boundary set, the simulation of the special structure process successfully. The specify velocity fields are gained.A PIV test is carried out on the 2135 diesel, some velocity fields at different crank angles with its transverse section about the TDC are gained.Based on the simulation results, the difference of the corresponding fields between the normal cylinder and the special structure is made. At the same time, the velocity fields of the normal and the special structure at the specified transverse section with the same crank angles are analysed. By the contrasts from the theory and test, the thorough effect of the concave structure which play an important role in the formation of micro eddy flow is investigated.更多还原