Spray Evaporation in turbulent Flow: Numerical Calculations and Detailed Experiments by Phase-Doppler Anemometry

The present paper concerns experiments and numerical calculations of an isopropyl-alcohol spray evaporating in a co-flowing turbulent heated air flow. The measurements provided detailed inlet and boundary conditions for the numerical calculations and allowed the validation of the numerical method and models. Phase-Doppler anemometry was used in order to obtain the spatial change of the droplet size distribution and the correlation between droplet size and velocity throughout the flow field. Additionally, a reliable method based on the detection of the signal amplitudes was applied to determine the droplet mass flux. By integration of the droplet mass flux profiles, the global evaporation rates could be determined for different flow conditions. Numerical calculations of the evaporating spray were performed by the Eulerian/Lagrangian approach. The modelling of droplet evaporation is briefly reviewed prior to the description of the applied numerical models and methods. Calculations for a single phase flow showed good agreement with the experiments. Also for all of the droplet phase properties reasonable agreement with the experiments could be achieved and the global evaporation rates agreed well with the measurements.