Pf. Gao et al., Numerical prediction of the performance of a manifold sampler with a circular slit inlet in turbulent flow, J AEROS SCI, 30(3), 1999, pp. 299-312
The performance of a bioaerosol manifold sampler with a circular slit inlet
in a turbulent Bow field was modeled using a 3-D numerical approach. The s
tandard kappa-epsilon turbulence model was used for simulating the mean tur
bulent Bow, and the Lagrangian approach was used for predicting the particl
e trajectories. The ratios of wind velocities to sampler inlet velocities w
ere from 0.5 to 3.5. Calculations were conducted for particle sizes of 2, 8
, 15, and 26 mu m. The agreement between numerical and empirical sampling e
fficiencies was good. It was found that lower sampling efficiencies at high
R values were associated with increased positive pitch of the velocity vec
tors generated at the inlet slit. Unbalanced sampling velocities between th
e upstream and downstream arcs were found only at high R values. At an inle
t velocity of 0.8 m/s, sampling efficiencies for 15 mu m particles decrease
d about 24% as R was increased from 0.5 to 3.5. A similar effect was observ
ed at an inlet velocity of 0.4 m/s. Turbulence decreased sampling efficienc
y and was related to the sum of the magnitudes of the wind and sampling vel
ocity vectors. (C) 1999 Elsevier Science Ltd. All rights reserved.