PIV validation of the CFD simulation of single-phase velocity field in spiral jet mills

• The CFD gas velocity in spiral jet mills is compared to PIV experiments. • Qualitative and quantitative results are obtained for two operating conditions. • Numerical results are in very good accordance with measured one. • Deviations are found near the cover and bottom and in the nozzle expansion regions. On-site measurement of fluid velocity fields inside spiral jet mills is a very challenging task and an experimental validation of the CFD single-phase simulations has never been proposed and performed in literature. In this work, a comprehensive comparison between numerical and experimental velocity contours taken by PIV on a spiral jet mill with full optical accessibility is presented to assess the accuracy of the CFD predictions. The velocity is sampled on three planes at different micronization chamber heights and seven angular positions for two relevant operating conditions. A grid sensitivity study is conducted to determine optimal parameters minimizing the difference between numerical and experimental results. The validation revealed that both the qualitative comparison based on the flow contours and the quantitative analysis of the velocity magnitude profiles show very good agreement between CFD and PIV results, especially in the bulk, while minor deviations occur in the external toroidal part of the mill.