英语论文网

摘要：本论文通过对国内外同行管路系统研究成果的分析，以及对管路系统气体瞬变填充过程建模方法和气体动力学数值计算方法的深入研究和比较，以拉格朗日坐标下的一维非定常气体动力学方程组为基础，针对运载火箭一个典型增压气路系统及其系统组件，建立了典型气路系统高压氦气高速瞬变填充管路的流动过程的数学模型。并利用本论文的模型，采用完全守恒型差分格式的数值计算方法，用FORTRAN计算机语言编制了数值计算程序对该管路系统的非定常气动过程进行了数值计算，对不同算例的计算结果进行了分析和比较。

增压气路系统瞬变填充过程数值计算研究
Numerical Analysis of Transient Priming Process in Pressurization Gas Pipeline System

Abstract
Pressurization system is very important in a flight vehicle propulsion system. Using the normal temperature gaseous helium to pressurize is one of the important means in propellant tank pressurization system of liquid propellant rocket engine. The regular operation of pressurization system ensures propellant supplying steadily and the engine operating normally. But in the fast and transient priming process of high-pressure gaseous helium, the unsteady gas flow is likely to cause unsteady pressue, consequently brings on violent vibrations of the whole gas pipeline system, which can seriously destroy the structure of the system and make the pressurization system invalid. Therefore the study on the transient priming process of high-pressure gaseous helium in pressurizing gas pipeline system of a launch vehicle is significant.
This dissertation focused on a typical pressurization gas pipeline system of a launch vehicle. On the basis of conservative equations of continuous gaseous media, one-dimensional unsteady gas-dynamic equations in Lagrangian form were derived to describe compressible transient gas pipe flow, and dynamic equations of components including gas bottle, pressure reductor, orifice, and tee joint of the system were established. These components were considered as poits in the system. Accordingly a total dynamic mathematical model of a pressurization gas pipeline system was established.
For this model, Lagrangian mass grids were established in the pipeline system. One-dimensional unsteady gas-dynamic equations in Lagrangian form of pipe flow were calculated in the fully conservative finite difference scheme, and Classical Runge-Kutta method was used to calculate the dynamic equations of other components of this system.
Based on the mathematical model and numerical calculation methods, a numerical calculation program was implemented using FORTRAN computer language, which could be used to calculate the fast and transient pipeline priming process of high-pressure helium in the typical gas pipeline system of a launch vehicle. In this dissertation a typical transient priming process of the gas pipeline system was simulated with this program.
The calculated results show that the mathematical model and numerial calculation methods established in this thesis preferably described the fast and transient dynamic process of this system and provide a theoretical basis to analyze dynamic characteristics of the components such as pipelines and pressure reductor of pressurization gas pipeline system of a launch vehicle. These work makes a foundation for further studies on vibration of pressurization gas pipeline system and other relevant problems.

Key words: Pressurization system, Numerical calculation, Dynamic model, Lagrange coordinates

Contents
1 Introduction 1
1.1 Background 1
1.2 Research Status 2
1.2.1 Oscillation 2
1.2.2 Dynamic characteristics 2
1.3 Dissertation’s Structure 2
2 Basic Theory 3
3 Mathematical Model 5
4 Program 7
5 Examples and Results 9
Conclusion 11
References 13
Research Fruits 15
Acknowledgements 16
1 Introduction
1.1 Background