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ISSN Imprimir: 1093-3611
ISSN On-line: 1940-4360
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EVALUATION OF MODELS FOR COLLISIONAL SURFACE PRODUCTION WITHIN THE Σ–Y EULERIAN SPRAY ATOMIZATION MODEL
RESUMO
The Σ–Y Eulerian spray atomization model is suited for CFD simulations of high Weber and Reynolds number sprays. In this model, the spray is assumed to behave like a single phase turbulent flow. Two additional transport equations are introduced to describe the flow: A transport equation for the liquid mass fraction Y and another one for the surface density Σ. Among others, collisions of liquid droplets lead to production and destruction of Σ. In the work presented here, an expression for the collisional production term is evaluated by means of a numerical experiment featuring turbulent droplet collisions and droplet breakup: Generic droplet populations, described by an initial mean Weber number, and the shape of the initial droplet distribution are subject to turbulent velocity fluctuations leading to turbulent droplet collisions and droplet breakup. A stochastic droplet collision modeling algorithm is used to trigger collisions. The outcome of a collision is determined by a collision model proposed in the literature. Results show that a collisional production term can be obtained featuring the same form proposed in the literature which was hitherto postulated, but not demonstrated. Different approaches exist for the modeling parameters of the surface density production/destruction term. Therefore CFD simulations employing the Σ–Y model are performed applying different values for these parameters. The results indicate that especially the parameter concerning the equilibrium value for surface density has major influence.