Using quasi-DNS to investigate the deposition of elongated aerosol particles in a wavy channel flow

• Quasi-DNS and deposition of elongated particles are tested.
• Effect of particle elongation on the deposition velocity is investigated.
• In a highly roughened channel the deposition is unaffected by the particle elongation.
• Application to the deposition of radioactive dust in a high temperature reactor.

In gas-cooled high temperature reactors, the diffusion of the fission products into the graphite matrix causes a radioactive contamination of the carbonaceous dust. The contaminated graphite aerosol particles often exhibit large aspect ratios and deposit in complex geometries, which hinders a detailed experimental investigation. The use of quasi Direct Numerical Simulation (quasi-DNS) to simulate the turbulent flow in nuclear reactors has seen an increased interest over the last few years. The capabilities of a quasi-DNS to simulate the transport and the deposition of elongated particles in a wavy channel flow are presently tested. It is shown that quasi-DNS effectively predicts deposition and that, unlike the deposition in a plane channel flow, the particle aspect ratio has no significant effect on the overall deposition rate in a wavy channel. It is suggested that in numerical studies of particle deposition on a significantly roughened channel, the particle can be assumed to be spherical without affecting the results of the deposition study.