850 research outputs found
An efficient flamelet progress-variable method for modeling non-premixed flames in weak electric fields
Combustion stabilization and enhancement of the flammability limits are
mandatory objectives to improve nowadays combustion chambers. At this purpose,
the use of an electric field in the flame region provides a solution which is,
at the same time, easy to implement and effective to modify the flame
structure. The present work describes an efficient flamelet progress-variable
approach developed to model the fluid dynamics of flames immersed in an
electric field. The main feature of this model is that it can use complex
ionization mechanisms without increasing the computational cost of the
simulation. The model is based on the assumption that the combustion process is
not directly influenced by the electric field and has been tested using two
chemi-ionization mechanisms of different complexity in order to examine its
behavior with and without the presence of heavy anions in the mixture. Using a
one- and two-dimensional numerical test cases, the present approach has been
able to reproduce all the major aspects encountered when a flame is subject to
an imposed electric field and the main effects of the different chemical
mechanisms. Moreover, the proposed model is shown to produce a large reduction
in the computational cost, being able to shorten the time needed to perform a
simulation up to 40 times.Comment: 26 pages, 13 figures, paper accepted for publication on Computers and
Fluid
Desempenho reprodutivo de bovinos na sub-região dos Paiaguas do pantanal Mato-Grossense. I. Efeito da suplementação mineral e da idade de desmama sobre a idade e o peso ao primeiro parto.
Foram estudados os efeitos da suplementação mineral e da idade a desmama sobre a idade e o peso ao primeiro parto de novilhas aneloradas na sub-região de Paiaguas, do Pantanal Mato-Grossense, através de fatorial em delineamento inteiramente casualizado
Desempenho reprodutivo de bovinos na sub-região dos Paiaguas do Pantanal Mato-Grossense. II. Efeito da suplementação mineral sobre índices reprodutivos de novilhas.
Foi estudado o efeito da suplementação mineral sobre o desempenho reprodutivo de novilhas neloradas em pastagem nativa, no Pantanal Mato-Grossense
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