- 期刊
- OpenAccess
重力沉降式集塵設備之流場模擬
Simulation of Flow Field in the Collecting Equipment of Gravity Settling Type
摘要
重力沉降室爲重力沉降式之集塵設備，其基本原理爲利用排氣管的突張效果，減少氣流的速度，使重力對塵粒的影響加大而順利沉降，達到收集粉塵的目的。重力沉降室是利用塵粒本身的重量沉降，爲最簡單的集塵方法，尤其對於粒徑大的粉塵，效果更爲顯著。為了增加集塵效率，可在重力沉降室底部設置集塵棚架，以提高分離效率。本文以計算流力軟體，有限元素分析法，分別模擬簡單突擴管型、加掛一個集塵棚架型、加掛兩個集塵棚架型及加掛三個集塵棚架型等四種不同規劃的重力沉降室。根據模擬分析的結果，氣流通過突張區域時，均有減速及向下偏曲的現象。集塵棚架內，皆有慢速渦流的產生，渦流的曲度能幫助塵粒的沉降；而慢速的渦流，不易使塵粒再度揚起。因此，集塵棚架的設置，確實能提高分離效果，隨著集塵棚架設置個數的增加，效果更爲明顯。
並列摘要
A gravity settler is the collecting equipment of gravity settling type. A suddenly expanded chamber in the outlet portion constructs this device. The gas reduces its velocity when it reaches the expanded chamber and the suspension particles will settle down due to gravity force. The gravity settler, which uses particles'own weight in collecting dust, is the simplest device. Especially, the efficiency for the removal of the larger size particles will increase significantly. To increase the efficiency of collection, the collecting-shelves will be set beneath the bottom of the chamber. In this study, the flow fields in the gravity settlers without or with different numbers from one to three collecting-shelves were simulated by using the computational fluid dynamics (CFD) software which based on finite element method(FEM). The results showed that the gas velocity become slow and moved downward when it passes the region of the expansion chamber. In the collecting-shelves, a slow eddy would be generated. The curvature of the eddy would help particles being settled down and the slow velocity of eddy cannot rise particles up again. Therefore the collecting shelves would improve collection effects. The results also showed that particles collection effects become more significant when increasing the numbers of the collecting-shelves.