Computational Simulations of Spray Cooling with Air-Assist Injectors

A new computational procedure for simulating air-assist flat sprays with atomization is described and demonstrated for surface cooling applications. This procedure builds upon and utilizes findings from our previous work; particularly the integral form of the conservation equations which are used to derive explicit quadratic formulas for drop size. These formulations relate the local energetic state to initial drop size produced by primary atomization processes. In this manner, the local liquid and gas phase velocities prior to atomization are used in the quadratic formula to provide the initial drop size and the appropriate local velocities are utilized as the initial droplet momentum state in a discrete particle tracking algorithm. This procedure has been performed and compared to experimental data for drop size and velocity. This furnishes a platform to further study the effects of droplet distributions on heat transfer and momentum transfer between the spray and a heated metal surface. This approach is based on the conservation principles and generalizable, so that it can easily be implemented in any spray geometry for accurate and efficient computations of two-phase flows including spray cooling.