The boundary condition at the valve for numerical modelling of transient pipe flow with fluid structure interaction

21st Fluid Mechanics Conference

物理学;力学

Henclik, S.^1

Department of Hydraulic Machinery, Institute of Fluid-Flow Machinery, Polish Academy of Sciences, ul. J. Fiszera 14, 80-231 Gdansk, Poland^1

关键词: Dynamic fluid structure interactions;    Fluid structure couplings;    Hydraulic characteristic;    Mounting systems;    Numerical tests;    Time dependence;    Transient flow;    Transient pipe flow;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/530/1/012034/pdf
DOI  :  10.1088/1742-6596/530/1/012034

学科分类：力学，机械学

来源: IOP

【 摘 要 】

Transient flows in pipes (water hammer = WH) do appear in various situations and the accompanying pressure waves may involve serious perturbations in system functioning. To model these effects properly in the case of elastic pipe the dynamic fluid-structure interaction (FSI) should be taken into account. Fluid-structure couplings appear in various manners and the junction coupling is considered to be the strongest. This effect can be especially significant if the pipe can move as a whole body, which is possible when all its supports are not rigid. In the current paper a similar effect is numerically modelled. The pipe is fixed rigidly, but the valve at the end has a spring-dashpot mounting system, thus its motion is possible when WH is excited by the valve closuring. The boundary condition at the moving valve is modelled as a differential equation of motion. The valve hydraulic characteristics during closuring period are assumed by a time dependence of its loss factor. Preliminary numerical tests of that algorithm were done with an own computer program and it was found that the proper valve fixing system may produce significant lowering of WH pressures.