Numerical Modeling of Water Impingement and Heat Transfer With Solid Slabs During Secondary Cooling in a Continuous Caster

Abstract

In the steel continuous casting process, cooling water is directly injected through multiple rows of nozzles to remove heat from the slab to allow the slab to solidify in secondary cooling. Effective heat removal from the slab without causing slab cracking and deformation is desired. The present study focuses on developing a reliable numerical model which can accurately predict the impingement and heat transfer between water droplet and solid slab. The flat fan atomizer is chosen as a representative nozzle to be simulated. The spray pattern on the slab surface, as well as the impingement behaviors of water droplets, are obtained through an Eulerian-Lagrangian approach. The wall jet model coupled with modified evaporation rate depending on the droplet Weber number has been applied in the numerical model. A series of parametric studies have been performed to investigate the effects of spray direction, standoff distance, and distance between adjacent nozzles on the impingement heat transfer process. Simulation results reveal that intense cooling effects can be found in the center of the spray, where the concentration of droplets is the highest regardless of the spray direction. Double the standoff distance can reduce the heat transfer coefficient on slab surface by 10%. Finally, the distance between two adjacent nozzles should be adjusted to be smaller than the standoff distance in order to avoid the “fountain” effect induced by the collision of the two neighboring wall jets.