NUMERICAL STUDY OF AIR-ATOMIZED WATER MIST COOLING OF A HEATED FLAT PLATE

摘要

The present numerical study describes the phenomena of impingement cooling of a heated flat surface by air and water mist-jet for mass loading fraction f = 0.003-0.024 at Re-dhyd = 4500 and h/d = 5. A multiphase two-dimensional axisym-metric, incompressible and turbulent flow is considered in the present study. The results obtained using the standard k-epsilon, standard k-omega, RNG k-epsilon, realizable k-epsilon, and SST k-omega turbulence models were analyzed and discussed. The predictions of the local heat transfer coefficient show that the realizable k-epsilon turbulence model predicts heat transfer results better than other turbulence models. The comparative study was performed to select a suitable multiphase model among the volume of fluid, mixture, and Eulerian models. The Eulerian multiphase model predicts heat transfer from mist-jet impingement on a flat surface much better than the volume of fluid and mixture multiphase models. Normalized axial and radial velocities of the continuous and dispersed phase are presented to understand the fluid flow. The present numerical study also discusses turbulent kinetic energy near the nozzle exit and volume fraction over the heated flat surface.