A Universal Aerosol Sampling Probe for High Efficiency Particle sampling from flowing gas streams

An aerosol sampling inlet has been developed to collect representative samples from the flowing gas stream. The inlet is referred to as the “Universal Aerosol Sampling Probe” because it is capable of efficient sampling over a wide range of free stream velocity without the need to change either the probe tip or sampling flow rate. It is a multi‐nozzle device consisting of one or more outer nozzles to extract a sample isokinetically and decelerate it from the relatively high stream velocity to a relatively low velocity. An inner nozzle is then used to extract a representative particle sample for delivery to the impactor or other particle collectors placed downstream. The approach enables a representative particle sample to be extracted at a fixed flow rate, irrespective of the velocity of the gas stream in which the probe is placed. The theoretical considerations leading to the design of such a universal probe are described. It is followed by the description of an experimental evalution of a prototype device. Good agreement was found between the experimental results and the theoretical prediction.