Measurements and CFD modeling of a pulverized coal flame with emphasis on ash deposition

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• 作者：A.M. Beckmann^a ; ^{beckmann@ievb.tu-clausthal.de" class="auth_mail" title="E-mail the corresponding author} ; M. Mancini^a ; R. Weber^a ; S. Seebold^b ; M. Mü ; ller^b
• 关键词：CFD ; Coal combustion ; Fly ash deposition ; Impaction efficiency ; Sticking efficiency
• 刊名：Fuel
• 出版年：2016
• 出版时间：1 March 2016
• 年：2016
• 卷：167
• 期：Complete
• 页码：168-179
• 全文大小：1713 K

文摘

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 1193X&_mathId=si62.gif&_user=111111111&_pii=S001623611501193X&_rdoc=1&_issn=00162361&md5=68806778bc8a936b34f40aaea227edd8" title="Click to view the MathML source">2×10^-9$2\times {10}^{-9}$ J. Inertial impaction and thermophoresis have been identified as main mechanisms of particle transport towards the deposition surfaces. Deposition rates on air-cooled probes (1193X&_mathId=si63.gif&_user=111111111&_pii=S001623611501193X&_rdoc=1&_issn=00162361&md5=b76ad4a39d513ba3554ba4c4ea786774">1193X-si63.gif">$600''–''700°$C surface temperature) have been measured to be 24% (Port 2) and 79.4% (Port 3) larger than those measured on uncooled probes (1193X&_mathId=si64.gif&_user=111111111&_pii=S001623611501193X&_rdoc=1&_issn=00162361&md5=f5e661bc2306b5f5b1ff8004d71c9773">1193X-si64.gif">$1150°$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.