Abstract: To enable quantitative characterization of particle transport performance in stack effluent sampling nozzles, a shrouded sampling nozzle was designed in compliance with ISO 2889,"Sampling of airborne radioactive materials from stacks and ventilation ducts of nuclear facilities",and a transport ratio testing method was developed, and experimentally validated. Results show that at the design sampling flow rate of 100 L/min and free-stream velocities ranging from 8.0 to 12.0 m/s, the transport ratio remained within 1.00 to 1.10, meeting the ISO-recommended range of 0.80 to 1.30. Good agreement was observed between experimental data and theoretical predictions, with relative errors below 10%. These results indicate that the proposed nozzle exhibits stable particle transport behavior under the target operating conditions, fully complying with the acceptance criteria.

Key words: shrouded sampling nozzle, transport ratio, aerosol, particle size, stack effluent