Theoretical and experimental evaluation of aerosol capture mechanism and the determination of the quality of fibers filters (HEPA and ULPA) as used in nuclear industry

In this paper, theoretical and experimental evaluation of aerosol capture mechanisms and the determination of the efficiency of fiber filters High efficiency particulate air filter and Ultra low penetration air filter as used in the nuclear industry is reported. The contribution of diffusion, interception and inertia impaction mechanisms on the filter efficiency was considered theoretically. A filter test tunnel was designed and constructed in order to serve for the study of particles capture efficiency of the fiber filter by the Di Octhyl Phtalate method. The filter efficiency as a function of particle sizes, air flow and filter characteristics has been studied. Other factors such as, pressure drop of the filter verous the air flow was also determined. Our investigations show that: The maximum penetration of the filters are in the range of 0.1 to 0.12μm of the particle diameters. The Ultra Low Penetration Air filter efficiency is considerably higher than the High Efficiency Particulate Air filter. The filter efficiency is directly proportional to the air flow rate, fiber diameter and porosity of the filter media in the range of particles size. With a fixed flow rate, the efficiency and the pressure drop decreases as the filter area increases. The pressure drop of these filters is directly proportional to the air flow rate