A turbulence‐induced coalescence model for fluid particle incorporating particle size effect across full energy spectrum

Abstract Accurately predicting fluid particle coalescence in turbulence remains challenging due to its inherent randomness and disorder. This study develops an improved turbulence‐induced coalescence model for fluid particles that incorporates particle size effect based on full turbulence energy spectrum. The proposed model considers the dynamic response of fluid particles to fluctuating velocity fields and the inertial lag relative to turbulent eddies, deriving a scale‐dependent velocity correction that accounts for discrepancies between fluid particles and eddies of comparable size. A comparative analysis of turbulence energy spectrum and velocity correction effects on coalescence behaviors under various conditions is conducted. The model accuracy is validated by comparing predicted bubble size distribution (BSD) with experimental data under different conditions. Moreover, in multiphase systems where turbulence‐induced coalescence dominates while wake entrainment‐induced coalescence also significantly influences BSD evolution, accurate size predictions can be achieved by combining the present model with our previously developed wake‐induced coalescence model.