Research On Filtration Performances Of HEPA Filters In Airliner Cabin Environmental Control System

With rapid economic development and improving people's living standards, it makes more and more people travel by aircraft. Recently, however, SARS, tuberculosis and other diseases spread world widely and nanometer particles is produced by airport, which caused a panic around the world. Many studies have shown that air travel is a major carrier which spread disease worldwide. The aircraft itself (such as APU, aircraft engines) will release a lot of ultra-fine particles; ultrafine particles will enter the lungs or the bloodstream, thereby seriously affecting people's lives and health. To this end, a number of research institutions (such as Purdue University, Built Environment Research lab in Tianjin University) are exploring innovative healthy, safe cabin environment technologies. Cabin air recirculation filter is a good tool which effectively removes bacteria, viruses, ultrafine particles.This paper first starts from the basic theory of filtration, and then analyzes filter mechanism, structure for cabin air recirculation filter and other factors affecting the filter performance. Cabin air recirculation filter test system is built according to EN1822 standard and is evaluated by using counting efficiency. Meanwhile, the test system is also equipped with a world leader experiment instrument such as aerosol generating and monitoring system, nanometer particle generator, Tianjin University independently developed solid particles generator and so on. Cabin air filter test system was calibrated carefully (such as flow sensors, pressure sensors, aerosol sampling system, etc.), and calibration results show that the errors are allowed in the standard range. Built cabin air filter test system, cabin air filter test system calibration method and nanometer particle test method have great reference value for further study.In the past people have been concerned about the high efficiency filter performance for sub-micron particle and almost no one studies the filtering of nanometer particles. This article focuses on studies of the air filter on the nanometer particle filter performance, and mainly explore the effects of air volume on the cabin high efficiency filter , cabin high efficiency filter dust holding capacity ,relationship between air volume and pressure drop for cabin air filter , nanometer particle size distribution of aerosol generator and so on. Meanwhile, the roads, airports, indoor, residential nanometer-particle size distribution is also measured. The results show that cabin high efficiency filter air filtration efficiency decrease as the air volume increase, while increasing the air volume will cause the most penetrating particle size to shift smaller particle size, which is consistent with theoretical predictions. The MPPS of initial products is about 160 nm, while the most penetrating particle size of second-generation products is about 50 nm. Road Sub-micron particles are more than the airport Sub-micron particle, but airport nanometer particles are much higher than the road nanometer particles.This study has some theoretical significance and practical significance for cabin high efficiency filters standardization of evaluation methods and development and optimization of cabin high efficiency filters.