Abstract
Euler/Lagrange Computations of Sprays Produced by Different Liquids using a Generalised Stochastic Droplet Collision Model
Highlights
Introduction turbulent sprays have been numerically computed for many years on the basis of the parcel-based Euler/Lagrange approach (Dukowicz, 1980; ORourke, 1982), a reliable prediction is not yet possible as an accurate and generalised droplet collision model is still missing
The collision model needs to properly determine the collision outcome which may be bouncing, coalescence or separation. This decision is based on so-called collision maps (i.e. the non-dimensional impact parameter B (i.e. B = 2 b⁄(dS + dL) with b the droplet lateral displacement and dS and dL the diameters of small and large droplets) versus the collision Weber (i.e. We = (ρ dS ur2el)⁄σ)) number whose structure strongly depends on the kind of liquid considered (demonstrated by: Sommerfeld and Kuschel (2016); Finotello et al (2018a); Sommerfeld and Pasternak (2019); Al-Dirawi and Bayly (2019))
The lower bouncing boundary including dissipation effects was developed considering a large number of new experimental data
Summary
Turbulent sprays have been numerically computed for many years on the basis of the parcel-based Euler/Lagrange approach (Dukowicz, 1980; ORourke, 1982), a reliable prediction is not yet possible as an accurate and generalised droplet collision model is still missing. The results for this constant including the old data (Sommerfeld and Pasternak 2019) and some recent measurements are shown in Figure 1 for pure fluids and solutions, respectively. Based on numerical simulations with interface reconstruction (i.e. VOF, volume of fluid method) Hu et al (2017) introduced a dissipation term in the energy balance which resulted in an additional parameter in the boundary line equation, valid for equal sized droplets: (1+ Δ3) (1+∆2) (4 φ1 − 12) (1−α1) (1− B2) Δ2 (9)
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