軸流式旋風集塵器之性能分析

Abstract

本文利用數值方法對軸流式旋風集塵器內部流場及其內固體微粒 之飛行軌跡進行研究與分析。本文利用有限體積法先求出集塵器內的 流場分佈而流場則以k-紊流模式加以模擬，再利用所求得的流場分佈 代入微粒運動方程式以求得單一微粒之運動軌跡進而求出其收集效率， 接著再改變入口葉片角度以改善其收集效率。結果顯示，在相同入口 流速下，粒徑愈小的微粒愈不易被收集。而入口流速愈大則集塵器的 收集效率愈佳。在入口位置的影響方面，由較靠近圓周壁位置進入集 塵器的微粒其收集的效果愈好。根據此一結果，所提出改變入口結構 的方法可以使固體微粒在進入集塵器時往圓周壁的方向偏移，而達到 提高收集效率的目的。

A study is to ivnestigate a flow field and trajectories of powder in a axial flow cyclone numerically. A finite volume method is used to solve the flow field in the cyclone. During the computing process, k-ε turbulent model is assumed to solve the governing equations of the flow field, and substitute the flow field into the particle motion equation to get the trajectories of the powder and compute the collection efficiency of the cyclone simutaneously. In the situation of the same inlet velocity, it is more difficult for a smaller particle to be collected, and the collection efficiency is better as the inlet velocity is fast. Besides, the powder flow into the cyclone near the outer side are more easily to be collected. According to the above results, a method is suggested to change the angle of the blade to make the powder move tothe outer side as the powder flow into the cyclone which results in improving the collection efficiency of the cyclone remarkably.