SIMPLIFIED MODEL OF HEAT-TRANSFER CRISIS IN ROD BUNDLES

The article proposes a simple model that describes the dependence of the critical heat flux on the parameters. The appearance of a crisis is studied in a long, heated bundle of rods into which unheated water delivered while a mixture with a small amount of steam flows out. On the initial section, where the temperature of the rod walls has not reached the saturation point, the heat flowing from the walls is removed by convection of a single-phase liquid. When the wall temperature is above the saturation point, steam bubbles form on the rod wall and move along it without detaching, and a two-phase boundary layer forms. Detailed methods of calculating the liquid flow rate in the boundary layer have still not been developed. As the Weber number increases, the liquid flow rate in the boundary layer in a film decreases.