黏性颗粒在聚偏氟乙烯纤维膜内部沉积特性数值模拟

Numerical simulation of deposition characteristics of viscous particles on the surface of polyvinylidene fluoride membrane

为了探究黏性颗粒在纤维过滤介质上的沉积特性,通过随机算法建立聚偏氟乙烯纤维膜的三维模型,并采用离散单元法进行了纤维膜内部的气固流动模拟,引入JKR颗粒接触模型,研究了颗粒表面能与碰撞恢复系数对黏性颗粒的运动与沉积特性影响,获得了黏性颗粒在纤维表面沉积的最佳表面能和碰撞恢复系数,并在此基础上研究了粒径2~7μm黏性颗粒的沉积与受力情况。结果表明:颗粒表面能、恢复系数与粒径均为影响黏性颗粒沉积特性的重要因素,表面能的减小,恢复系数或粒径的增大,能够使捕集效率增大,颗粒在纤维表面更易形成稳定的沉积与团聚形态。

To explore the deposition characteristics of viscous particles on fibrous filters, a 3 D model of PVDF membrane was established by a stochastic algorithm, and the discrete element method was adopted to simulate the gas-solid flow in the fiber membrane. The JKR particle contact model was introduced to investigate the effects of particle surface energy and inter-particle collision recovery coefficient on the movement and deposition characteristics of viscous particles, the best surface energy and collision recovery coefficient for viscous particles deposited on the surface of fiber were obtained. Then, the deposition of viscous particles with a particle size of 2-7 μm was simulated. The results indicate that the particle surface energy, restitution coefficient and particle size are all significant elements influencing the deposition characteristics of viscous particles. The decrease of surface energy and the increase of restitution coefficient or particle size can increase the capture efficiency. The particles are more likely to form stable deposition and agglomeration forms on the fiber surface.