管系内一维可压缩流动数值建模与特性分析

针对复杂管系内可压缩流体,基于有限体积法,采用HLLC(Harten-Lax-vanLeerContact)格式和黎曼求解器构建了有限控制体数值离散方法,引入虚拟节点用于连接有限控制体,借助虚拟节点给出控制体之间数值通量的计算格式,发展了一种管道内一维流动数值建模方法。针对含有分支管路的管系,在管道连接部位构建了分支管路拟一维流动数值计算模型。基于所发展的一维流动数值方法,建立了变径管道和含60°分支管道内流动计算模型,验证了该方法的收敛性和有效性;基于虚拟节点的数值格式处理变径管激波问题具有一定精度优势。研究了变径管和分支管模型中可压缩流体激波、稀疏波等的传播机理,分析了管径对相邻支管压力的影响,为工程管路设计提供了参考。

Numerical modeling and analysis of one-dimensional compressible flow in pipeline

Based on the finite volume method(FVM), and the HLLC(Harten-Lax-van Leer Contact) scheme combined with the Riemann solver, a numerical method for computing compressible flow in complex pipeline is established. The concept of the ghost cell is introduced to calculate the numerical flux between adjacent finite control volumes. Consequently, a one-dimensional numerical model for fluid in pipeline is adopted. A quasi-one-dimensional numerical model for fluid is developed for the junction of pipe network, in which the pipe is modeled. Based on the above numerical method for pipeline, numerical models for flow in a reducer and a 60° branch pipeline are established. The effectiveness and convergence of the present method are validated. The ghost cell scheme has particular advantage on computing shock waves in reducers. The propagation mechanisms of shock wave and rarefaction wave of the compressible fluid in reducers and branch pipes are analyzed. The effect of the pipe diameter on the fluid pressure of adjacent pipes is discussed.