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 CaCO3 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 CaCO3 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.

Dian-Guang Liu;Yun Yang;Cheng-Jun Mao;Jian-Feng Wu;Ji-Chun Wu

School of Earth Sciences and Engineering,Hohai University,Nanjing 211100,China;Key Laboratory of Surficial Geochemistry,Ministry of Education Department of Hydrosciences,School of Earth Sciences and Engineering,Nanjing University,Nanjing 210023,China

地球科学学刊（英文版）

[1]Dian-Guang Liu;Yun Yang;Cheng-Jun Mao;Jian-Feng Wu;Ji-Chun Wu-.A Comparative Study on Hydrodynamics and Hydrochemistry Coupled Simulations of Drainage Pipe Crystallization Blockage in Karst Tunnels)[J].地球科学学刊（英文版）,2022(05):1179-1189

Hydrochemistry,blockages,crystallizationinduced

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