空气过滤器过滤效率测试中非等速采样误差分析

Non-lsokinetic Sampling Relative Error Analysis of Air Filter's Filtration Efficiency Testing

从理论上计算分析了非等速采样对空气过滤器过滤效率测试所带来的误差。结果表明:非等速采样给大颗粒过滤效率测试带来的误差更大;当粒子计数器采用2.83 L/min小流量进行采样时,采用内径为3.0 mm^10.0 mm的采样管能够保证在国标《空气过滤器》(GB/T 14295-2008)规定的粒径范围和迎面风速条件下,由非等速采样带来的误差控制在±5%以内,满足采样误差允许要求。此外,建议采用2.83 L/min小流量进行采样时,采样管内径取4.5mm较为合理,这样不仅能够更好地降低空气过滤器过滤效率测试中的非等速采样误差,也能在更大迎面风速范围内满足测试要求。

Error introduced by non-isokinetic sampling for air filter＇s filtration efficiency testing is analyzed in theory. The results show that bigger error is introduced for larger particle by non-isokinetic sampling. When Optic particle counter （OPC） with airflow of 2.83L/min is used in testing, the relative error of non-isokinetic sampling is within ±5% under the particle size and face velocity conditions proposed in standard of 〈〈Air filter〉〉 （GB/T 14295-2008） for sample probe of 3.0mm-10.0mm inner diameter. Beside, inner diameter of 4.5mm is proposed when 2.83L/min airflow OPC is used, which can reduce the non-isokinetic sampling error more, and meet bigger range face velocities.