粒径和渗流速度对多孔介质中悬浮颗粒迁移和沉积特性的耦合影响

COUPLED EFFECTS OF PARTICLE SIZE AND FLOW RATE ON CHARACTERISTICS OF PARTICLE TRANSPORTATION AND DEPOSITION IN POROUS MEDIA

关于粒径和渗流速度的研究对更好地描述悬浮颗粒的迁移和沉积过程有着重要的意义。在不同的粒径和渗流速度条件下进行悬浮颗粒的室内土柱试验,对比分析不同条件下穿透曲线的变化规律。试验很好地克服了悬浮颗粒形状和化学因素等对试验结果的影响。试验结果表明,对于粒径相同的悬浮颗粒来说,流出液中悬浮颗粒的浓度峰值随渗流速度增大而增大,相应的沉积颗粒却随之减小;并且,渗流速度存在一个临界值(0.173 cm/s),大于该临界值,渗流速度的变化对悬浮颗粒的迁移特性的影响很小。其次,渗流速度相同时,流出液中悬浮颗粒的浓度峰值随粒径增大而减小,相应的沉积颗粒却随之增大;渗流速度越小,粒径对筛滤作用的影响越明显。

Particle size and flow rate play an important role in particle transportation and deposition in porous media. Different suspended particles were studied under different flow rates in soil columns tests, and the corresponding breakthrough curves were analyzed. The effects of particle shape and chemical factors on test results were excluded from the tests. Test results Show that the peak concentration of effluent increases and the quantity of deposition particle decreases with the increasing flow rate for the same particle size. However, the deposition particle decreases with the increasing flow rate. There exists a critical flow rate of 0.173 cm/s, and the effect of flow rate on particle transportation can be negligible when the flow rate is larger than the critical value. On the other hand, the peak concentration of effluent decreases and deposition increases with the increasing particle size for the same flow rate. Furthermore, the effect of particle size on particle straining is obvious at low flow rate.