Influence of scale on flow and cavitation characteristics of vortex-based hydrodynamic cavitation devices

Vortex-based hydrodynamic cavitation devices (VDs) are widely used in water treatment, biomass pretreatment, emulsification, and crystallization, yet the effect of scale on flow and cavitation characteristics remains unclear. This work investigates geometrically similar scale-up using a validated turbulence and cavitation modelling framework over a wide range of throat diameters (dt[jls-end-space/]) and velocities (vt[jls-end-space/]), spanning nearly three orders of magnitude in flow rate (∼100–103 LPM). Correlations were developed for key parameters, including Euler number (Eu), swirl ratio (ratio of the maximum tangential velocity, vθ,max and vt[jls-end-space/]), Reynolds number ((Formula presented) ), and vapor volume (Vvap[jls-end-space/]). Results show that Eu varies linearly with the square of the swirl ratio, and a correlation is proposed to estimate swirl ratio as a function of dt and (Formula presented). With increasing scale, cavitation extent (ratio of generated vapour volume and the device volume) and specific energy dissipation rate decrease even at constant energy consumption per unit mass, indicating reduced device performance. Scale-up also affects cavitation-zone parameters such as volume-averaged pressure, pressure fluctuation amplitude, and turbulence frequency, for which predictive correlations are developed. The approach and the presented results provide a quantitative basis for the design and scale-up of hydrodynamic cavitation devices.