Deposition of fine aerosols in laminar tube flow at high temperature with large gas-to-wall temperature gradients

Abstract

This work provides experimental data on thermophoretic deposition of submicron aerosols ( 2 < Kn < 30 ) in laminar tube flow at temperatures of 400 – 600 ∘ C and gas-to-wall temperature differences of 300 – 400 ∘ C . This range is significantly higher than in previous experiments and of technical interest. Fluid flow in a cylindrical tube as well as aerosol transport and deposition in the thermal gradient were simulated using a CFD computer code (Fluent) and the Talbot expression for the thermophoretic velocity, with the thermophoretic coefficient α t as a fit parameter. It was found that a constant value of α t = 0.55 was an acceptable choice for engineering applications, to accurately estimate thermophoretic deposition efficiencies and deposition rates in the range of particle sizes (20–200 nm) and gas temperatures ( 130 – 580 ∘ C ) which were covered in the experiments.