Target efficiency comparison between free stream ribbon and surface-mounted ribbon in a turbulent flow

The effect of solid boundary under a surface-mounted ribbon on particle collection efficiency was studied. The turbulent fluid velocity was obtained by solving the Navier-Stokes equation based on k-ε turbulence model. The trajectory model was adopted to obtain the information on the particle phase trajectories. The equation of particle motion included inertial, viscous drag and gravity forces. To check the validity of numerical results, target efficiency of particles over the free-stream ribbon with respect to Stockes number was compared with the same experimental data. It was observed that the agreement between these is excellent. For the surface-mounted ribbon, the target efficiency in the range of small Stokes numbers is larger than that for the free-stream ribbon, but for larger Stockes number is smaller. The Stokes and gravity numbers were introduced to interpret the effect of gravity and inertial impaction on particle deposition at the back and front of the surface-mounted ribbon. The dominant deposition mechanism inertial impaction, gravity force) over the surface-mounted ribbon depends on Stokes and gravity numbers