This paper deals with the quantification of the sealing effectiveness of slot- and joint-type
leaks by aerosol deposits. A sticky aerosol (MMD ≈ 4.9 μm; GSD ≈ 2.7) was injected
into a duct and blown out through machined slot- and joint-type leaks located on the duct
wall. For both leak-types, the crack exit was a rectangular opening of 1.7 x 50 mm. The
pressure across the leaks was kept constant during the plugging process, while the airflow
rate through the openings was continuously monitored. The deposition patterns were
recorded and the average deposition efficiencies were obtained through the measurement
of the particle mass collected in the crack. Instantaneous sealing rates were obtained from
the leakage airflow time series. The Normalized Sealing Rate (NSR) introduced in this
paper allows one to compare the instantaneous sealing efficiencies as the leaks are
subjected to various boundary conditions. For our specific leak geometries and boundary
conditions, the three key results of these experiments are that: a) inertial impaction near
the entry point is the major cause of the decline of the leakage flow rate for either type of
leak; b) the pressure variations in the 100-400 Pa range do not have a significant effect on
the average deposition efficiency; c) the average deposition efficiency of the slot- and
joint-type leaks used are in the range of 25% and 85%, respectively. We also observed
that there exists a critical joint-leak size below which the NSR decreases significantly.