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Master's Dissertation
DOI
https://doi.org/10.11606/D.18.1999.tde-17062024-122439
Document
Author
Full name
Luben Cabezas Gómez
Institute/School/College
Knowledge Area
Date of Defense
Published
São Carlos, 1999
Supervisor
Committee
Milioli, Fernando Eduardo (President)
Cuminato, José Alberto
Seleghim Junior, Paulo
Title in Portuguese
Um estudo da modelagem matemática e solução numérica de escoamentos bifásicos gás-sólidos
Keywords in Portuguese
escoamentos bifásicos gás-sólido
fluidização
modelagem numérica
modelo das duas fases
Abstract in Portuguese
Foi desenvolvido um estudo inicial de modelagem hidrodinâmica de escoamentos bifásicos gás-sólidos, sendo consideradas a formulação matemática e a técnica numérica de solução. O sistema de equações conservativas diferenciais parciais foi obtidocom base no modelo das duas fases, considerando ambas as fases como meios contínuos. Primeiramente, foram formuladas as equações locais instantâneas e as condições de salto. Posteriormente, aplicando o procedimento de médias de Euler, foramobtidas, para ambas as fases, as equações conservativas médias. Finalmente, foram formuladas as leis de fechamento, as condições iniciais e de contorno. As equações diferenciais parciais médias foram discretizadas num volume de controleEuleriano. As equações de continuidade foram discretizadas implicitamente, eqnuanto as equações de momentum o foram através de um procedimento explícito-implícito. Foram desenvolvidas simulações numéricas para uma geometria vertical típica deleitos fluidizados circulantes, e para um tubo ascendente aberto. Foram obtidos resultados em regime transiente, que mostram a instabilidade hidrodinâmica característica destes escoamentos, com recirculação e desenvolvimento de aglomerados
Title in English
An study of mathematical modelling and numerical solution of gas~solid two-phase flows
Keywords in English
fiuidization
numerical modeling
two-fluid model
two-phase gas-solid flow
Abstract in English
An initial study was carried out on hydrodynamics modelling of gas-solid two-phase flows. Both mathematíical formuliation and numerical solution technique were considered. A system of conservative partial diferential equations was derived based on the two-fluid model conception, under the continuum hypothesis for both phases. Firstly the local instantaneous equations and jump conditíons were derived. The Eulerian averaging procedure was then applied and average conservative equations were derived for each phase. Finally, closing laws, boundary and initial conditions were formulated. The average parcial differential equations were discretized over an Eulerian control volume. The continuity equations were implícitly discretized, while the momentum equations were discretized folowing an explicit-implicit procedure. Numerical simulations were performed for a vertical geometry typical to circulating fluidized beds, and for an open vertical riser. Transient resulís were generated wich showed the characteristic hydrodynamic instability of the flow field, with recirculations and development of clusters.
 
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Publishing Date
2024-06-17
 
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