A numerical study of the sampling efficiency of a tube sampler operating in calm air facing both vertically upwards and downwards

摘要: In this paper the performance of a thin-walled sampling tube operating in calm air, pointing both vertically upwards and downwards, is investigated. The problem considered mathematically sampler modelled as long circular cylinder. Two mathematical models have been developed to determine flow field around sampler, one model assumes potential other takes into account viscous effects flow. From detailed knowledge airflow, paths suspended particles fluid were calculated aspiration efficiency determined. dependence upon particle size suction rate are for various conditions comparison made with available experimental data. results obtained using two different compared hence assuming flow, an assumption often when studying aerosol sampling, It found that neglecting higher predicted value efficiency, A. However, all cases considered, difference values A never large general behaviour always same.