Migration and deposition behavior of silica powder in saturated sand: coupled effects of temperature and flow rate

作者：Cui, Xianze; Li, Jin; Fei, Wenbin; Wen, Tao; Ding, Shengyong; He, Siyuan; Fan, Yong^*

来源：GRANULAR MATTER, 2022, 24(3): 95.

DOI：10.1007/s10035-022-01254-2

• Groundwater heat pump
• Natural sand
• Particle migration
• Temperature
• Percolation rate

To explore the effects of temperature and percolation velocity on the migration and deposition characteristics of different silica powder in saturated porous media under continuous injection conditions, migration-deposition tests were conducted for four combinations of particle sizes at different temperatures (5 degrees C, 15 degrees C, 25 degrees C, 35 degrees C) and different flow rates (0.032 cm/s, 0.063 cm/s, 0.095 cm/s), and deposition pictures were obtained under the microscope. The analytical solution of the convective dispersion equation of first-order deposition dynamics is demonstrated to be able to describe the penetration curve of suspended particles. With increasing seepage velocity and temperature, the sedimentation coefficient and longitudinal dispersion coefficient increase. The test results showed that the higher the temperature was, the lower the peak relative concentration of the effluent particles at the same percolation rate; the faster the flow rate was, the higher the peak relative concentration of the effluent particles at the same temperature, and both higher temperature and faster flow rate accelerated the migration of particles so that the pore ratio corresponding to the peak concentration was reduced. The effect of the two on the particles was the same; temperature was the main control factor in the test run at a low flow rate, and the effect of temperature was not obvious at a high flow rate. Thus, temperature and flow rate are important factors affecting the migration of suspended particles in saturated porous media.

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