Combined effect of thermophoretic force and other influencing parameters on the particle deposition rate on a tilted rough surface

摘要

In this study a modified v2-f turbulence model, (φ-α), is used to simulate a non-isothermal air flow. The model is compatible with a two-phase Eulerian approach to predict the deposition rate of particles on cooled and warm tilted rough surfaces. The effects of drag force, lift force, turbophoretic force, thermophoreric force, electrostatic force, gravitational force and Brownian/turbulent diffusion as well as the surface roughness were examined on the particle deposition rate. The combined effects of the thermophertic force with electrostatic force/surface roughness/tilt angle on the particle deposition rate were investigated separately. This study highlights the paramount effect of thermophoretic force for a cooled surface on the particle deposition rate and clearly shows that when the temperature difference exceeds a certain limit the electrostatic force/the surface roughness/tilt angle has insignificant effect on the particle deposition rate. The effect of electrostatic force and roughness on the particle deposition rate becomes insignificant for small-size particles while the effect of tilt angle on the particle deposition rate becomes insignificant at intermediate-size particles. Furthermore, the results surprisingly show that when the wall temperature is higher than the flow temperature, increasing the temperature difference reduces the effect of electrostatic force and the surface roughness on the particle deposition rate for small-size particles.