Numerical study of bubble break-up in bubbly flows using a deterministic Euler–Lagrange framework

• A simulation framework for heterogeneous bubbly flow is presented.
• A Lagrangian breakup model is proposed.
• The daughter size distribution does not influence the bubble size distribution (BSD).
• The critical Weber number and superficial gas velocity significantly affect the BSD.

In this work we present a numerical model to predict the bubble size distribution in turbulent bubbly flows. The continuous phase is described by the volume-averaged Navier–Stokes equations, which are solved on an Eulerian grid, whereas the dispersed or bubble phase is treated in a Lagrangian manner, where each individual bubble is tracked throughout the computational domain. Collisions between bubbles are described by means of a hard-sphere model. Coalescence of bubbles is modeled via a stochastic inter-particle encounter model. A break-up model is implemented with a break-up constraint on the basis of a critical Weber value augmented with a model for the daughter size distribution. A numerical parameter study is performed of the bubble break-up model implemented in the deterministic Euler–Lagrange framework and its effect on the bubble size distribution (BSD) is reported. A square bubble column operated at a superficial gas velocity of 2 cm/s is chosen as a simulation base case to evaluate the parameters. The parameters that are varied are the values of the critical Weber number (WecritWecrit), the daughter size distribution (β  ) and the superficial gas velocity (vsupvsup). Changes in the values of WecritWecrit and vsupvsup have a significant impact on the overall BSD, while a different shaped β did not show a significant difference.

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