Study of flow and heat transfer characteristics of saturated flow film boiling over two inline cylinders

Abstract

In this article, a numerical investigation carried out on saturated flow film boiling over two cylinders placed in an inline arrangement has been discussed. Water at near critical condition, p/pc = 0.99, is considered for all simulations, where pc is the critical pressure of water. In this study, buoyancy assisted flow is considered. The effects of different liquid Reynolds number ReD and wall superheat on heat transfer rates are studied for different spacings between the two cylinders. Interface structures and their modes of evolution greatly vary for different cases investigated. For some cases, especially for those with lower spacing between the cylinders, a steady vapor column connecting both cylinders in the gap region between them is formed. At higher flow rates, the vapor column in the gap region is unstable. At some cases where re-circulation zones are formed, the vapor column breaks off. The heat transfer rate from the rear cylinder is significantly affected by the modes of the phase-interface evolution and the types of flow structures formed in the gap region between the cylinders. It is found that the flow structures and the phase-interface evolution are strongly dependent on the distance between the two cylinders for a given Reynolds number and a non-dimensional wall superheat.