Research On Performance Of HEPA Filter Supply Outlet Diffusion Panel

The proportion of unidirectional airflow clean room in the clean room usage as a whole is about 95%. HEPA supply outlet, the last units of air cleaning and conditioning supply air system, supplies clean air into clean room. By dilution effect, it reduces indoor air pollution and exhausts dirty air from return outlet or exit outlet. HEPA supply outlet diffusion panel is very important to air pattern of unidirectional airflow clean room. Now there is big difference with perforation ratio of HEPA supply outlet diffusion panel. It is about from 7% to 20%. This thesis is researched on the diffusion effect of the perforation ratio of the panel. In the foundation of AIRPAK2.1 edition of FLUENT commercial software, the thesis adopts standard K-εtwo equation model and momentum method to build up HEPA supply outlet CFD model. The supply air and indoor air distribution of the most used three types of HEPA supply outlet GF01-1.0,GF01-0.5 and GF03-1.0, with diffusion panel under different perforation ratio are numerical simulated. Indoor velocity field and cleanliness recovery characteristic is measured with type of GF01-1.0 under different perforation, in the condition of supply air volume 200m3/h. Supply air volume and static pressure before diffusion panel in different conditions of supply air volume 200m3/h, 404m3/h, 570m3/h and 735m3/h are measured with diffusion panel. By means of smoke and suspending thread, air pattern of diffusion panel is watched in the condition of supply air volume 700 m3/h. Through comparing and analyzing experience data and numerical simulation result, perforation ratios of type GF01-1.0 HEPA supply outlet diffusion panel are provided, in the two conditions of supply air volume 200m3/h and 700m3/h. In the foundation of numerical simulation, combined with experience result of type GF01-1.0, GF01-0.5 and GF03-1.0 perforation ratios are suggested. This research is very important for unidirectional airflow clean room to optimize structure of HEPA supply outlet, improve jet, uniform indoor air distribution, reduce vortex flow zone and return flow zone, uniform clean room pollution concentration field and reduce cleanliness recovery characteristic.