Analysis of Internal Flow in Bag Filter by Different Inlet Angle

Abstract

A bag filter (BF) acts as an air pollution control device that removes particulates out of the air from commercial processes. Few industries, especially food manufacturing, is often to use BF to control the emission of air pollutants. This study aims to investigate the pressure drop in BF by different inlet angles. The study was developed by Computational Fluid Dynamic (CFD) to perform the result. There are five sets which are 180°, 225°, 270°, 315° and 360° of BF configurations develop which the selection flow model is RANS (for steady-state) and the inlet opening remain constant at 45°. There is a need for this study to reduce the pressure drop as an improvement to run exhaust fan with a lower percentage or capacity as could reduce the electric consumption for operational cost. Therefore, the lower exhaust fan specification will be determined, which may reduce future installation costs. The turbulence model used in this study is RNG k-ε with swirl dominated flow to resolve flow in BF with better accuracy. The filter domain in this study was defined as porous media with some properties. The simulation shows the lowest pressure drop is achieved by configuration 360° compared to other configurations (180°, 225°, 270°, and 315°) by 7.46%. As a conclusion, the highest pressure drop occurs at configuration 180° (original design) where the smallest inlet angle contributes higher pressure at the inlet duct compared to other configurations. In contrast, the lowest pressure drop occurs at configuration 360° (improvement design) where the biggest inlet angle contributes lower pressure at the inlet duct compared to other configurations and more uniform on its distribution. The three configurations in between original and improvement design show that the changes are directly proportional – consistent. This evidences can help to reduce the pressure drop in BF operation where savings energy generated on exhaust fan electric consumption.