Particle deposition in a turbulent boundary layer over a large particle size spectrum
In many applications deposition of small particles, enhanced by turbulence and temperature gradients, can cause damage to surfaces or lead to heat transfer reduction. The steep velocity and temperature gradients in the turbulent boundary layer are mainly responsible for the deposition processes. In recent resuspension and deposition tests during the STORM experiments it became apparent that, even for small temperature gradients, the coupled effect of turbulence and thermophoresis enhances particle deposition significantly. Tests, which are performed in a way that aims to exclude heat transfer over the boundaries, show in the simulation for the remaining temperature gradient an increase of particle deposition for a log-normally distributed particle size spectrum due to positive thermophoresis. For the same particle size distribution almost no influence of the lift force (according to Saffmann) can be seen in the calculation. It is shown in the calculation that one deposition model including thermophoresis, but not considering Brownian motion or temperature fluctuations, gives acceptable results for a complete particle spectrum.
Bibliographic Reference: Paper presented: Seventh International Symposium on Gas-Particle Flows, Vancouver (CA), June 22-26, 1997
Availability: Available from (1) as Paper EN 40625 ORA
Record Number: 199710819 / Last updated on: 1997-07-02
Original language: en
Available languages: en