Analysis And Simulation Of Flow Characteristics In Solid-liquid Two Phase Flow

Solid-liquid two-phase flow is a common multiphase flow phenomenon,which widely exists in many fields in nature and industry.In the petrochemical industry,due to the existence of solid phase in the medium,the characteristics of its flow field are different from that of single-phase flow,which is easy to induce unstable flows such as vibration and cavitation.At the same time,the impact caused by solid phase will lead to the thinning of containers and equipment and the reduction of service life.Therefore,solid-liquid two-phase flow experiment and numerical simulation analysis in a specific environment are very necessary and have research significance for the determination of flow principle and the safe operation of equipment.This paper takes the common valve system in chemical pipeline as the research object and establishes the flow channel model formed by the pipeline inside and both sides of the valve.The finite element analysis tool Fluent was used to characterize solid particles with discrete phase model,and the internal flow field of solid and liquid two-phase media before and after passing through the valve was simulated and analyzed.The main flow results such as the characteristics of the flow field,the distribution of pressure and velocity,the trajectory of particles and the resulting erosion rate were obtained.The results indicate that in the process of rotation valve from opening to closing,import and export of differential pressure,the maximum velocity,pipe wall erosion rate all increase,and the growth rate of these three increases rapidly with the decrease of the valve opening.The pressure difference and the maximum flow rate increase exponentially,while the erosion rate increases by leaps and bounds around one third of the opening degree;In the process of valve rotation,fluid vortex cluster is generated behind the valve,leading to the emergence of the low-pressure area.Meanwhile,particles gather in the vortex cluster and are not easy to flow out.With the increase of the rotation Angle,the area of the vortex cluster and the low pressure area expands,and the linear density of particle track in the vortex cluster increases,resulting in enhanced flow instability;One side wall inside the valve and the intersection between the valve outlet and the pipeline are the main areas of erosion.In order to further analyze the influencing factors of solid-liquid two-phase flow and pipeline erosion rate,the flow parameters and solid phase parameters are changed to simulate the flow field under different flow rates,different particle mass flow rates and different particle diameters.The results show that with the increase of steady flow velocity,the inlet and outlet pressure difference increase,the vortex cluster intensifies,and the pipeline erosion rate increases;The change of particle mass flow rate and particle diameter does not affect the distribution of flow field.The increase of particle mass flow rate increases the erosion rate of pipeline,and the increase of particle diameter decreases the erosion rate of pipeline.