Modeling Primary Atomization

Abstract

This review concerns recent progress in primary atomization modeling. The numerical approaches based on direct simulation are described first. Although direct numerical simulation (DNS) offers the potential to study the physical processes during primary atomization in detail, thereby supplementing experimental diagnostics, it also introduces severe numerical challenges. We outline these challenges and the numerical methods to address them, highlighting some recent efforts in performing detailed simulation of the primary atomization process. The second part is devoted to phenomenological models of primary atomization. Because earlier conventional models of breakup are well reported in the available literature, we highlight only two recent developments: (a) stochastic simulation of the liquid jet depletion in the framework of fragmentation under scaling symmetry and (b) primary atomization in terms of Reynolds-averaged Navier-Stokes (RANS) mixing with a strong variation of density.

Quadratic formula for determining the drop size in pressure-atomized sprays with and without swirl

“…We may reason that this is the same effect observed in our energy balance, where the jet speed is representative of the kinetic energy and zero Weber number corresponds to no kinetic energy available to be converted to surface energy, and therefore infinite drop size as in Figures 2 and 3. Figure 3 shows experimental data by Rimbert and Castanet, 27 who obtained detailed statistics of drop size and velocity in swirl sprays. The data shown in Figure 3 are the most probable drop size at a given liquid velocity, which illustrate the utility of Eq.…”

“…The only term to be modeled is the viscous dissipation (the Reynolds number effect); however, we have found a mathematically 29 and physically (Figure 1) reasonable form. There are quasi-DNS results on spray atomization 27 with which the only adjustable constant, K, in the current formulation can be evaluated. Also, further work may be needed in accurately specifying the spray "control volume," since the current approach only links the initial and final asymptotic states.…”

A conservative and well-balanced surface tension model

“…Interface break-up is a key mechanism in many two-phase flow applications such as spray atomization [8], oil trapping in porous media [15], and foam generation [12]. In this example we study the break-up of a bubble due to variable surface tension.…”

Size distributions of sprays produced by violent wave impacts on vertical sea walls

“…One approach to modelling the spray is to use a PDF to represent the probable number of droplets with certain diameters and velocities in a given region [13][14][15][16][17]. The RosinRammler distribution was suggested [18] and has been found to be appropriate for many types of atomization spray [19].…”