Falling water films over vertical surfaces due to orthogonal water jet impingement

Abstract

In AHWR rod bundle assembly, LOCA could cause failure of the system due to overheating. To overcome this problem, it is proposed to introduce holes in the axial and circumferential direction of central water tube so that water discharges through these holes in the form of a jet and strikes the high-temperature fuel rods resulting in their cooling by gravity-driven flow mechanism. This cooling involves a different mechanism of heat transfer such as two-phase flow, single phase jet impingement, droplet impingement, evaporation, natural convection, and radiation due to the high temperature of the fuel rods. Among all these heat transfer mechanisms, the present study focuses on the horizontal water jet impingement on a vertically oriented surface. The scarcity of research in such cases is the motivation to study the hydrodynamics of the water jet impingement on a vertically oriented surface. A proper understanding of hydrodynamics of the water film on a vertical surface is important in the understanding of heat removal processes. Present study discusses the hydrodynamics of falling water films on a flat surface and a curved surface exposed to horizontal water jet impingement. Effect of the jet exit to surface distance (Z/d), Reynolds number, nozzle diameter (d), and the ratio of curvature of the surface to the diameter of the pipe (D/d) were examined on lateral and vertical spread of the water film at vertically oriented flat and curved surface.