Study On Optimization Of The Mixing Devices In Testing System Of Hepa Filter

With the development of air cleaning technology, the requirement for the performance and quality of high efficiency particulate air (HEPA) filter become higher and higher. Today, in China, the testing technology and standards of HEPA has been in constant development, but the testing system is too large to fit for the little space of in-situ test. Therefore, it is necessary to optimize HEPA filter testing system. In view of this, this paper optimizes the mixing device in the HEPA filter testing system, combining the experiments and computational fluid dynamics (CFD) simulations.In the subject, some mixing devices were studied, such as reducer duct, reducer duct with blind plate, fan or orifice plate and mixing orifice with blind plate, to overcome the deficiency of the present mixing device. Referring to the Japanese standard(JIS B9927 clean room air filter test methods), physical model and math model was built, and reducer duct and mixing orifice with blind plate were studied adopting numerical simulation method. On the basis of the numerical simulation results, the testing platform is built. Then reducer duct with blind plate, fan or orifice plate were studied in the help of experiments. The thesis gives contrast analysis of air velocity uniformity and aerosol uniformity.Through the study of optimizing the mixing devices, reducer duct with fan has better effect in mixing of aerosol and air velocity than other devices.