【作者】 齐迎春；

【导师】 李风；

【作者基本信息】 吉林大学 ， 机械设计， 2004， 硕士

【摘要】 液力变矩器是液力传动的重要元件之一，是由带叶片的泵轮、涡轮、导轮组成的流道封闭的多叶轮透平机械，液体在流道内做复杂的三维粘性非定常紊流流动，过去无论是实验方法还是理论方法，准确分析工作介质在各元件内的流动状况都有相当的难度。计算流体动力学（CFD）是20世纪60年代伴随计算机技术迅速崛起的学科。经过半个世纪的迅猛发展，这门学科在理论和应用方面都已接近成熟，成熟的一个重要标志是近十年来，各种CFD通用软件包的陆续出现，成为商业化软件。他们主要是用来求解流体力学中的Navier-stokes方程。本文在UG和ANSYS软件的基础上对液力变矩器的内部流场进行研究。通过求解N-S方程来获得液力变矩器的内部流场，但是由于计算软件和计算流体力学本身存在的一些不太完善的假设的存在，使得计算过程还有许多需要解决的问题。第一章介绍了选题背景和本文的研究内容。数值模拟也叫计算机模拟，它具有耗费小、时间短、省人力的优点，同时它具有很好的重复性，条件易于控制，可重复模拟过程，这对紊流的数值模拟尤为重要。文章首先介绍了数值模拟技术的发展和它在流场计算和分析中的应用，并介绍了几种流场分析软件，证实了数值模拟是一种对液力变矩器的内部流场进研究的很好的方法，ANSYS软件以它的独有的优点完全可以承担这个任务；接着介绍了流场分析的理论和设计方法的发展和现状；并简要介绍了流场测试的几种方法。第二章主要介绍有限元的解题原理和思路。有限元法作为有效的数值模拟方法在计算流体力学中起着越来越重要的作用，它不仅用于线性问题，而且逐步推广到非线性问题，如流体力学中的复杂非线性方程N—S方程的求解，用有限元法可以得到很好的效果。因此文章介绍了有限元数学基础即变分原理、里兹法和加权余量法，并结合本论文研究的重点液力变矩器介绍了有限元解题的步骤。第三章的基本内容是ANSYS中的CFD（计算流体力学）的理论基础。首先推导出流场计算的基本方程，因为液力变矩器中流体的流动处于紊流状态，因此对雷诺方程进行了介绍，并分析了几种紊流模型，论述了各个模型的特点。<WP=93>用有限元法解流体动力学方程涉及到偏微分方程的离散即流体流动矩阵进行了推导，文中ANSYS的方程离散化方法作了简要地介绍。ANSYS同时给出的求解偏微分方程的速度—压力耦合算法的求解器，并对求解的收敛性和稳定性进行了介绍：收敛准则、控制收敛的方法和稳定求解的原理。第四章的内容主要建立液力变矩器内部流场的计算模型和给出流场的计算条件。在本章中首先提出了研究液力变矩器流场的几个约定和一些假设，对流场进行了适当的简化，以便于分析。然后，利用UG软件建立叶轮流道的三维模型，并将该模型导入到ANSYS中划分计算网格。流道的进口边界条件设为速度边界条件，出口设为压力边界条件，其它设为壁面边界条件。在ANSYS中提供了很多的紊流模型、离散格式和速度—压力耦合算法，在本文中对各种模型和算法的特点进行了说明。为了选择最适合本文研究内容的模型和算法，设置了多组算例，分别对不同的模型和算法进行了对比分析，最后确定紊流模型使用标准模型，速度—压力耦合算法使用SIMPLEN算法，离散格式采用单调流线逆风算法（MSU）。在本章的最后，给出了各工况下流道进口的初始速度，提出了循环计算的收敛条件，作为循环计算结束的标准，并以流程图的形式描述了流场数值计算的步骤。第五章中对计算得到的起动工况（i=0）、速比（i=0.4）、最高效率工况（i=0.718）和速比（i=0.8）四种工况的流场作了定性分析，并与Y. Dongh和B. Lakshminarayana的计算结果进行了对比。第六章对全文进行了总结，阐述了论文所做的主要工作和研究成果。更多还原

【Abstract】 The hydraulic torque convert is one of the most important parts in hydraulic transmission and it is composed of three rotor wheel, pump rotor, turbine and guide wheel. The fluid in interval channel is in the state of three-dimensional viscous time-dependent flow and so it is very difficult to analysis and observe the flow condition neither with theoretical method nor with tentative method. The computational fluid dynamics (CFD) grown up with the development of computer in the 1960s and after almost fifty years, its theorem and application all get mature. The most obvious symbol is the emergence of all sort of software of CFD and their purpose is solving the most classical equation of Navier-stokes. In this dissertation we will study the interval flow of hydraulic torque converter with UG and ANSYS software. But because of the limitation of computing method and the hypothesis in CFD, the result of the computing with software still have many place needing ameliorating. The first part describes the surrounding of the project and explains the object matter of this paper. Numerical simulation is also called computer simulation and it has many merit such as minor consume, small time-spending and saving manual and at the same time it can repeat computing and be easy controlling that is very important for cosmically simulation such as turbulence. In the start of the paper the development of numerical simulation and the application of it in flow field calculation and simulation are introduced; several soft wares in this direction are mentioned and argue that numerical investigation is a best way to make research on the internal flow of the torque convert and depending its merits ANSYS can finish this task; after that generalize the development and actuality of theory and design method of the torque convert in this part, and briefly describe several test method of the flow. Bring forward the intention and context of this dissertation at last.Theory and reason of finite element method is introduced in the second part. As an effective numerical simulation plan, FEM is more and more important in CFD and it not only is applied in linear problem, but also in non-linear problem, such as the resolve of complicated N-S equation in CFD and getting satisfactory <WP=95>result. For us getting a good understand of this method, the basic math method of finite element is introduced such as variation principle, Ritz method and weighted residual method. United to hydraulic torque converter, the step of this method is given. The main point of the third is the theoretical basis of CFD in ANSYS. First deduce the basic control formula of the hydrodynamics and because of the turbulence of flow in flow field, formula Renault is given and analyzes several flow models in the numerical calculation, and discuss the physical meanings of the model. In order to resolve the partial differential equation, we describe the formation of the numerical calculation and contrast several common numerical calculations and mainly several discrete methods and the basic idea of velocity-pressure coupling method and for making a further theory base for analyzing with software ANSYS, some necessary step are referred like convergence criterion and the control of convergence and stabilization.Put forward to the calculation model of the flow field and calculation condition of flow. First the regulation and the hypothesis of the torque converts flow was brought forward and predigest the flow to analyze. Then establish the three-dimension model of the impeller passage with UG soft and put the model into the girding caved up by the ANSYS. Suppose the inlet boundary of the flow way to velocity boundary condition, and suppose outlet to pressure boundary condition, and suppose other to wall boundary condition. There are many turbulence model 、discrimination methods and velocity-pressure couple methods in ANSYS. This dissertation explained all kinds of models and methods. In order to choose the best model and method, the dissertation set up many examples to contrast an更多还原