Abstract
Configuration of piping-pressure safety valve (PPSV) is widely used but may sometimes show instabilities, which should be avoided or reduced. For exploring the cause of these instabilities, Computational Fluid Dynamics (CFD) provides a powerful tool that can be used not only to reproduce the system-level responses, but also to get the details of the local flows. However, the results of CFD simulations are usually sensitive to their model settings, thus, to ensure accuracy, effects of certain critical model settings (such as time-step size and turbulence model) on transient simulations should be determined. In this paper, a 2-D axisymmetric mesh model is developed first, which can be used to predict the dynamic responds of a PPSV system. With this model, three levels of time-steps are tested. The results indicate that the time-step of 1e−5 is a reasonable choice for transient simulations of the PPSV system. After that, a total of four two-equation turbulence models are used for transient simulations. The results indicate that the SST (Shear stress transport) k-omega model produce the closest results to the experiments. After that, the accuracy of the developed CFD model (with 1e−5s time-step and SST k-omega setting) is verified by experimental tests. The results indicate that the developed CFD model can accurately reproduce the dynamic responds of the PPSV system. Outcomes obtained in this paper can not only provide a reference for the transient CFD model development, but also verify the applicability and high accuracy of 2-D axisymmetric CFD models in PPSV dynamics prediction.
