Numerical Simulation Of Gas-solid Phase Flow Field In The Chamber Of A Feeding Equipment For Fine Powders

Adding high performance adsorbent to filter tips is a widely used technology to reduce the tar and harmful components of cigrette smoke. Fiber tow is the basic component of filter tips, and the adsorbent added is fine powers in general. The distribution of the powders is realized by the feeding equipment. In this paper, such an equipment was analysed. When it works, powders fall onto the fiber tow from the hopper. As the powders are very tiny and its falling speed is very low, the moving speed of the fiber tow is relatively high, so flow disturbance will be produced leading to the problems such uneven distribution, powders flying out of the feeding chamber with the air. As a result, the feeding quality couldn't be guaranteed. And the waste of powders will be serious too.The basic reason for the problems above is that the fine powders will move with the disturbance air flow. In fact, the motion process of the powders is a complicated gas-solid phase motion, including the reaction between the air and the powders. So it would costs more to study the performance of the feeding equipment in experiment only. And the research cycle would be longer too. The numerical simulation method used in this paper could overcome these shortcomings.In this paper, based on the software FLUENT, the gas-solid phase flow field in the chamber of the feeding equipment was numerically simulated. On the foundation of the study about the numerical simulation method of the gas-solid phase flow field, the gas flow field in the feeding chamber was simulated based on the simplified model. And the influence to the gas flow field caused by the structure parameters and operating conditions were studied. Then the particle phase was added to the simulation, and the particle moving trajectories were simulated. The distribution of the powders with different diameters on the fiber tow was simulated by the particles. And the loss ratio of the powders was also calculated. According to the simulation results, the feeding equipment was optimized aim at the no ideal distribution.The simulation of the gas flow filed has shown its distribution in the chamber. It also shown the influence law about the back plates' angles and the tow's moving speed on the gas phase flow. And the simulation of the gas-solid phase flow field has shown the moving trajectories of the particles. On the base of the analysis of the trajectories, this paper proposed the definition about the large powders and small powders. And the motion of the powders with different character in different casting mode was researched The results show that the performance of the equipment will be good when the particles are large, bad when small. A theme for optimizing the equipment was proposed according to the results.