Influence of energy spectrum distribution on drop breakage in turbulent flows

• The influence of energy spectrum on drop breakage was studied.
• Drop breakage should be modeled in the wide energy spectrum range.
• A breakage model in terms of general energy spectrum function was presented.
• This model can explain the recent experimental phenomena theoretically.

This work focused on the influence of energy spectrum distribution on drop breakage in turbulent flows. An improved breakage model in terms of general energy spectrum function was presented. It can be coupled with available forms of energy spectrum and can be applied to the wider operating conditions such as the wider size range of drops. Unlike previous work that only considered the inertia subrange spectrum, this work simulated the breakage in the framework of wide energy spectrum and accounted for the necessity of considering the wide energy spectrum distribution. The improved model coupled with wide energy spectrum function can theoretically explain the recent experimental phenomena observed by Maaß and Kraume, 2012. Determination of breakage rates using single drop experiments. Chem. Eng. Sci. 70, 146–164. That is, breakage frequency increases to a maximum and then decreases with increasing parent drop size. This is because the non-monotone energy spectrum function can distinguish three spectrum ranges, i.e., containing-energy range, inertia subrange and dissipation range, and the treatment that parent drop size always falls in the inertia subrange is no longer required in this work. While when only the energy spectrum of inertia subrange is applied to the whole size range of eddies, the predicted breakage frequency monotonously increases with parent drop diameter. Therefore, the energy spectrum distribution has a crucial influence on the evolution of the breakage frequency with parent drop size.

As shown in this figure, the breakage frequency predicted by the proposed model coupled with energy spectrum function SMA or SMB increases to a maximum and then decreases with increasing parent drop diameter. Furthermore, SMA or SMB showed a non-monotone distribution with wave number. However, the breakage frequency predicted by the proposed model coupled with energy spectrum function SIS monotonously increases with parent droplet diameter and the energy spectrum always increases with decreasing wave number.Figure optionsDownload high-quality image (132 K)Download as PowerPoint slide