Spray plume shape can be visualized with using Computational Fluid Dynamics (CFD) by applying a substantially low iso-surface of a spray concentration value. In FLUENT‘s CFD code, spray concentration is automatically calculated while applying discrete phase model (DPM). This method has been previously used in gas cooling and spray-drying applications, where the spray plume was loosely defined with low concentration value. Visualization of spray plume shape and wall attachment (wall wetting) aids in the assessment, correction and optimization of spray nozzle placement with respect to targeted gas cooling temperature reduction and minimal wall wetting. To omit loosely defined Spray Plume Boundary (SPB) value, a stricter requirement for SPB was imposed through experimentally obtained data. The spray was injected in co-flow configuration within the wind tunnel with square cross-sectional size of 0.6 x0. 6 m2 at air speed of 15.4 m/s. To correlate the experimental SPB with CFD based value, the numerical results were compareded for the Sauter-Mean Diameter and volume flux distribution data. The experimental results were acquired with an Artium Phase Doppler Interferometer.

Based on validated criterion for SPB evaluated at 20 C, the same system was evaluated computationally with increased air inlet temperatures at 100, 400, 700 and 1000 C. To evaluate the effect of temperature on evaporation, the spray plume shape was analyzed with DPM concentration (DPMC) values, air temperature reduction between inlet and an outlet, and percentage of water evaporation inside of spray plume. As air stream temperature and evaporation rate of water droplets were increased, the SPB which was represented by DPMC iso-surfaces became more sensitive to the evaporation process. The percentage of evaporation rate measured inside spray plume‘s SPB with DPMC value validated at 20 C (DPMC= 0.0004 kg/m3) decreased from 96.6% at 20 C to 73.7% at 1000 C. The percentage evaporation rate inside the spray plume increased with a decrease in the DPMC value for the SPB.