R. J. Issa, West Texas A&M University, Canyon, TX
During the last several decades, air-assisted water sprays have been widely used in many cooling applications in the hot strip rolling mill; however, the understanding of air-assisted water sprays in the cooling of the strip bottom surface on the run-out table is still very limited. A numerical model is developed to simulate the spray impaction and heat transfer mechanisms for the cooling of a downward-facing surface heated to temperatures above Leidenfrost point. This paper addresses the general characteristics of air-assisted water sprays. The objective of this study is to provide insight into the optimal flow conditions for best heat transfer enhancement. The technical issues that are addressed include: understanding of the spray transport phenomenon, air-to-water loading, nozzle-to-surface distance, droplet impaction efficiency, and the desirable droplet size for the best operating conditions.
Summary: The purpose of this study is to establish an in-depth understanding of the heat transfer process for the air-assisted spray cooling of the strip bottom surface on the run-out table. The study shall provide insight into the optimal flow conditions, droplet size distribution, and air-to-liquid loading for best heat transfer enhancement and droplet impaction effectiveness. The study will not only advance the knowledge and understanding of air-assisted spray cooling within the heat transfer community but will also have a wide impact on the strip cooling in the hot rolling mill.
