轴向耦合水击振动方程的改进研究
发布时间：2019-03-15 18:06
【摘要】：对于充液管道系统,水击又是一种不可避免的水力暂态现象,其巨大水击压强给管道系统带来了很大的安全隐患,水击动态特性的研究则对实际的充液管道系统的有着特别重要的意义。而水击计算的可靠性与正确性则依赖于水击计算理论,不断完善和改进耦合水击计算的基本方程对于实际工程的应用具有着重要意义。 论文首先对传统的水击理论计算公式的推导、计算方法以及存在问题做了详细分析。我们已知,传统水击理论所用的连续性方程适用面较广,可用于任何恒定流或非恒定流的水力计算,但在发生水击时,管道内并存在液体压力波速、管道应力波速、流体流速,而经典的连续性方程并未能在微分方程中反映这个情况。另外,传统水击计算理论主要重点是研究流体的动力学行为对结构的影响分析,忽略了由于流体对结构运动状态改变而产生的流体运动变化,并且进行了大量的简化处理,这样导致一部分重要的系统信息丢失,不能更好的反应管道系统的实际运动状态。本文主要是基于现有的水击计算理论及其耦合理论,针对水击计算模型做进行进一步的分析和改进,提出用于计算耦合水击的基本连续性方程。 本文将新推导的连续性方程进中水击波速与流速关系更正为考虑管道在纵横两个方向都反映水击耦合特性的耦合波速。并进一步处理得到用于计算耦合水击的改进的基本连续性方程,与简化后的流体动量方程、管道运动方程及物理方程构成了改进的轴向4-方程模型。 将改进的轴向4-方程与文献[21]的数学模型对比分析,验证改进的4-方程模型用于耦合水击波的计算分析是可靠性、合理性。接着,利用特征线法将轴向4-方程模型进行变换,得到相对应的常微分方程,详细推导了特征方程计算各物理变量的迭代格式,及相应边界条件的处理。
[Abstract]:For the liquid-filled pipeline system, water hammer is also an inevitable hydraulic transient phenomenon, and its huge water hammer pressure brings a great security hazard to the pipeline system. The research on the dynamic characteristics of water hammer is of great significance to the actual liquid-filled pipeline system. The reliability and correctness of the water hammer calculation depend on the water hammer calculation theory. It is of great significance to improve and improve the basic equation of the coupling water hammer calculation for the practical engineering application. Firstly, the derivation, calculation method and existing problems of traditional water hammer theory are analyzed in detail. It is known that the continuity equation used in the traditional water hammer theory can be used in the hydraulic calculation of any constant or unsteady flow, but in the event of water hammer, there are also the velocity of the pressure wave, the velocity of the stress wave and the velocity of the fluid in the pipe, and the velocity of the pressure wave, the velocity of the stress wave and the velocity of the fluid exist in the pipeline. The classical continuity equation does not reflect this situation in the differential equation. In addition, the traditional water hammer calculation theory mainly focuses on the analysis of the influence of fluid dynamics on the structure, neglecting the fluid motion change due to the change of the fluid to the structure motion state, and carries on a lot of simplified treatment. This leads to the loss of some important system information and can not better reflect the actual motion state of the pipeline system. In this paper, based on the existing water hammer calculation theory and its coupling theory, further analysis and improvement are made to the calculation model of water hammer, and the basic continuity equation used to calculate the coupling water hammer is put forward. In this paper, the relationship between the velocity of water hammer wave and the velocity of water hammer is corrected to consider the coupling wave velocity which reflects the coupling characteristics of water hammer in the longitudinal and transverse directions of the pipeline. An improved axial 4-equation model with simplified fluid momentum equation, pipeline motion equation and physical equation has been obtained by further processing the improved basic continuity equation for the calculation of coupled water hammer, and the simplified equation of fluid momentum, the equation of pipe motion and the physical equation have been used to calculate the coupling water hammer. By comparing the improved axial 4-equation with the mathematical model in reference [21], it is proved that the improved 4-equation model is reliable and reasonable for the calculation and analysis of coupled water percussion waves. Then, the axial 4-equation model is transformed by the characteristic method, and the corresponding ordinary differential equation is obtained. The iterative scheme for calculating the physical variables of the characteristic equation and the treatment of the corresponding boundary conditions are derived in detail.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV134
本文编号：2440858
[Abstract]:For the liquid-filled pipeline system, water hammer is also an inevitable hydraulic transient phenomenon, and its huge water hammer pressure brings a great security hazard to the pipeline system. The research on the dynamic characteristics of water hammer is of great significance to the actual liquid-filled pipeline system. The reliability and correctness of the water hammer calculation depend on the water hammer calculation theory. It is of great significance to improve and improve the basic equation of the coupling water hammer calculation for the practical engineering application. Firstly, the derivation, calculation method and existing problems of traditional water hammer theory are analyzed in detail. It is known that the continuity equation used in the traditional water hammer theory can be used in the hydraulic calculation of any constant or unsteady flow, but in the event of water hammer, there are also the velocity of the pressure wave, the velocity of the stress wave and the velocity of the fluid in the pipe, and the velocity of the pressure wave, the velocity of the stress wave and the velocity of the fluid exist in the pipeline. The classical continuity equation does not reflect this situation in the differential equation. In addition, the traditional water hammer calculation theory mainly focuses on the analysis of the influence of fluid dynamics on the structure, neglecting the fluid motion change due to the change of the fluid to the structure motion state, and carries on a lot of simplified treatment. This leads to the loss of some important system information and can not better reflect the actual motion state of the pipeline system. In this paper, based on the existing water hammer calculation theory and its coupling theory, further analysis and improvement are made to the calculation model of water hammer, and the basic continuity equation used to calculate the coupling water hammer is put forward. In this paper, the relationship between the velocity of water hammer wave and the velocity of water hammer is corrected to consider the coupling wave velocity which reflects the coupling characteristics of water hammer in the longitudinal and transverse directions of the pipeline. An improved axial 4-equation model with simplified fluid momentum equation, pipeline motion equation and physical equation has been obtained by further processing the improved basic continuity equation for the calculation of coupled water hammer, and the simplified equation of fluid momentum, the equation of pipe motion and the physical equation have been used to calculate the coupling water hammer. By comparing the improved axial 4-equation with the mathematical model in reference [21], it is proved that the improved 4-equation model is reliable and reasonable for the calculation and analysis of coupled water percussion waves. Then, the axial 4-equation model is transformed by the characteristic method, and the corresponding ordinary differential equation is obtained. The iterative scheme for calculating the physical variables of the characteristic equation and the treatment of the corresponding boundary conditions are derived in detail.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV134
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