摘要
传统水击理论所用的连续方程未能反映水击发生时管道内存在的液体压力波速、管道应力波速、流体波速,且进行了大量的简化却不能更好地反应管道系统的实际运动状态。本文主要基于现有的水击计算理论及其耦合理论,在考虑管道纵横两个方向都反映水击耦合特性的情况下,利用特征线法,求出耦合波速;并在推导新的连续方程时将求出的耦合波速替代推导传统4-方程模型的连续性微分方程时水击波速与流速的关系,得到新的连续方程;并忽略高次微量和压力梯度等对新的连续方程进行一定简化,与简化后的流体动量方程、管道运动方程和物理方程构成了改进的轴向4-方程模型。将改进模型求解出的耦合波速与经典模型的进行比较,结果表明两耦合波速相近,但改进模型在考虑管道纵横两个方向都反映水击耦合特性的因素后,理论上会更严瑾、更合理。
The continuity equation of traditional water hammer theory can not reflect the liquid pressure wave velocity, the pipe stress wave velocity, and the fluid velocity exist in the pipeline when water hammer occurs. In addition, the pipe system couldn't reflect the real motion state very well due to too many simplifications. Based on the existed theory of water hammer and its coupled theory, the coupling characteristics of water hammer in vertical and horizontal orientation of the pipe are considered, and the coupled velocity is obtained by the method of characteristics. The solved coupled velocity substituted for the relationship of water hammer wave velocity and flow rate in deducing continuity differential equation of the traditional 4-equation model, and the new continuity equation is obtained. The new equation is much simplified, together with the simplified fluid momentum equation, the pipe motion equation and the pipe physics equation composes the improved axial 4-equation model. Compared the coupled velocity solved from the improved model with that solved from the classical model, these two coupled velocities are similar, but the improved model is more stringent and more reasonable in theory.
出处
《应用力学学报》
CAS
CSCD
北大核心
2016年第4期565-569,733,共5页
Chinese Journal of Applied Mechanics
基金
国家地区资金(51569011)
关键词
水击
FSI(流固耦合)
连续性方程
特征线法
相容方程
water hammer
FSI(fluid-structure interaction)
the equation of continuity
the method of characteristics
the compatibility equation
