Prediction of particle deposition from a turbulent stream around a surface-mounted ribbon

The flow field, particle trajectory, and deposition around a surfacemounted ribbon have been studied numerically. For obtaining the flow field, the time-average Navier-Stokes equations together with the two-equation k-e model of turbulence were solved numerically based on SIMPLE algorithm. The trajectory of particles was obtained by solving the equation of particle motion that included the inertial, viscous drag, and gravity forces. The Stokes (Stk) and gravity numbers (Nsg) were introduced for interpreting the particle transport around the ribbon. The target efficiency with respect to stokes number at zero gravity was calculated and compared with the experimental data. It is seen that except for small deviation between numerical results and experimental data in the range of small Stokes number, the agreement was very good. Particles are deposited around the ribbon due to inertial impaction and gravity force. The dominant deposition mechanism depends on Stokes and gravity numbers. The cumulative deposition efficiency of particles along the longitudinal direction for various Stokes and gravity numbers were calculated for interpreting the effect of these two mechanisms. It is seen that for large Stk, and small Nsg, the dominant deposition mechanism is the inertial impaction. On the other hand, the gravity force dominates the particle deposition for small Stk and large Nsg.