Measurements and CFD modeling of a pulverized coal flame with emphasis on ash deposition. (1st March 2016)

• Record Type: Journal Article
• Authors: Beckmann, A.M.; Mancini, M.; Weber, R.; Seebold, S.; Müller, M.
• Is Part Of: Fuel. Volume 167(2016)
• Page Start: 168
• Page End: 179
• Publication Date: 2016-03-01
• Subjects: CFD -- Coal combustion -- Fly ash deposition -- Impaction efficiency -- Sticking efficiency; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2015.11.043
• Languages: English
• ISSNs: 0016-2361

Abstract

Abstract: Measurements of fly ash deposition in a 15 kW pulverized coal jet flame and CFD-based mathematical modeling have been performed. The deposits have been collected at two ports at particle Stokes numbers in the 0.02–0.34 range and particle kinetic energies not larger than 2 × 10 - 9 J. Inertial impaction and thermophoresis have been identified as main mechanisms of particle transport towards the deposition surfaces. Deposition rates on air-cooled probes ( 600 – 700 ° C surface temperature) have been measured to be 24% (Port 2) and 79.4% (Port 3) larger than those measured on uncooled probes ( 1150 ° C surface temperature) due to the enhanced role of thermophoresis. Complex dependencies of the deposition rate on the probe surface temperature and the probe location have been observed. The CFD-model predictions are able to reproduce these dependencies after adjustments to the particle sticking sub-model. The paper contains estimations of both the impaction and sticking efficiencies.