Fortran壅塞式燃气阀芯通道内流场数值研究
时间:2018-05-10 21:44 来源:毕业论文 作者:毕业论文 点击:次
| 摘要本文用Fortran语言编写的程序对壅塞式燃气发生器内流场进行仿真研究。主要采用二文结构网格有限体积法，对流通量采用Steger-warming迎风格式进行离散。首先，用数值方法验证四个经典算例，证明程序是正确、可行的。利用无粘模型和三种湍流模型对内流场分别进行模拟，证明湍流对流场的影响不大。用无粘模型对三种结构进行计算，结果表明模型结构B的总压恢复系数较大；再利用无粘模型对B模型进行入口条件和出口反压对流场影响的研究；密度、静压和总压分布与入口总压成正比，而马赫数不受入口总压的影响；出口反压对流场内的流动几乎没有影响。通过对仿真结果的研究，本文得出了合适的计算模型和优化的结构，并得到了利用入口条件对流场分布进行控制的规律。22689 关键字 Fortran语言 流体仿真 结构选择 湍流模型 入口条件 出口反压 毕业设计说明书（毕业论文）外文摘要 Title Numerical Investigation of the Flow Field of Choked Gas Valve Core Channel Abstract This paper introduces a simulation research of the flow field in a steerable gas generator.2D symmetrical structured grids and finite volume scheme are used. Steger-warming scheme is used to discretize the convective fluxes. Four classical examples are computed to test the program. The results of inviscid model and turbulence model show that the turbulent eddy viscosity ratio and the turbulent kinetic energy are relatively small, which implies that the turbulence does not have an evident effect on the flow field. The inviscid model is then used to explore the best structure among three models A, B, and C. Model B is proved to have the highest recover coefficient in total pressure. In addition, the inviscid model is used to simulate the flow field in model B to test the influences of total pressure at the entry and the exit. Mach number is not affected by the total pressure at entry, while the distributions of density, local pressure, and total pressure are linear to the total pressure at entry. There is nearly no difference in the flow field with different total pressure at the exit. According to the research on the results above, this paper points out the proper computational model and optimized structure, and the principle to control the flow field by changing the situation at the entry. Keywords Fortran flow field simulation construction choosing conditions at entry total pressure at exit 目 次 1 绪论 1 1.1 课题的背景及意义 1 1.2 燃气发生器的发展现状 2 1.3 本文的主要工作 3 2 物理模型和数学方法 4 2.1 物理模型 4 2.2 控制方程 7 2.3 湍流模型 8 2.4 离散方法 11 2.5 边界条件 15 2.6 计算流程 16 3 数值验证 19 3.1 激波管问题 19 3.2 斜激波反射问题 21 3.3 前台阶问题 22 3.4 后台阶问题 24 4 无粘流与粘性流的对比 28 4.1 网格的划分 28 4.2 无粘流与有粘流流动效果的对比 28 (责任编辑：qin) |