Drainage pipe system is the requisite component of the traffic tunnels in Karst area.To reveal the dynamic process of crystallization blockage in drainage pipes,a novel hydrodynamics and hydrochemistry coupled simulat...Drainage pipe system is the requisite component of the traffic tunnels in Karst area.To reveal the dynamic process of crystallization blockage in drainage pipes,a novel hydrodynamics and hydrochemistry coupled simulation model was developed for calculating the deposition rate of CaCO_(3) fouling in pipeline surface.Sediments adhering to the pipe walls involve a deformable domain with moving geometric boundaries,and moving mesh and level set methods are proposed for simulation of for tunnel turbulence and crystallization fouling process.The simulation results are compared with the experimental results showing similar trend.The effects of temperature,flow velocity,and solution concentration on crystallization blockage were analyzed by comparative simulation studies.The simulation results show that:(1)the moving mesh method simulated nozzle shrinkage caused by crystalline deposition,without accounting for geometric topology shape changes.However,the level set method tracked the moving topology and thus can simulate the process of complete blockage;(2)the flow velocity in the longitudinal pipe generally exceeded that in the transverse pipe,and the CaCO_(3) crystal concentration in the transverse pipe eclipsed that in the longitudinal pipe,which meant crystallization blockages primarily occurred in the transverse pipe;(3)the temperature and concentration correlated positively with the crystallization rate,while the crystal precipitation value decreases with the increasing of inlet flow velocity increases.This study advances a hydrodynamics and hydrochemistry coupled crystallization blockage model to provide technical support for the early identification of crystallizationinduced pipe blockage in the drainage system in karst tunnel sites.展开更多
基金jointly supported by the National Key Research and Development Program of China(No.2019YFC1804304)the National Natural Science Foundation of China(No.U2167212)。
文摘Drainage pipe system is the requisite component of the traffic tunnels in Karst area.To reveal the dynamic process of crystallization blockage in drainage pipes,a novel hydrodynamics and hydrochemistry coupled simulation model was developed for calculating the deposition rate of CaCO_(3) fouling in pipeline surface.Sediments adhering to the pipe walls involve a deformable domain with moving geometric boundaries,and moving mesh and level set methods are proposed for simulation of for tunnel turbulence and crystallization fouling process.The simulation results are compared with the experimental results showing similar trend.The effects of temperature,flow velocity,and solution concentration on crystallization blockage were analyzed by comparative simulation studies.The simulation results show that:(1)the moving mesh method simulated nozzle shrinkage caused by crystalline deposition,without accounting for geometric topology shape changes.However,the level set method tracked the moving topology and thus can simulate the process of complete blockage;(2)the flow velocity in the longitudinal pipe generally exceeded that in the transverse pipe,and the CaCO_(3) crystal concentration in the transverse pipe eclipsed that in the longitudinal pipe,which meant crystallization blockages primarily occurred in the transverse pipe;(3)the temperature and concentration correlated positively with the crystallization rate,while the crystal precipitation value decreases with the increasing of inlet flow velocity increases.This study advances a hydrodynamics and hydrochemistry coupled crystallization blockage model to provide technical support for the early identification of crystallizationinduced pipe blockage in the drainage system in karst tunnel sites.
