Natural Convection Heat Transfer for a Concentric Tube Thermosiphon

Abstract

Natural convection heat transfer for a single-phase thermosiphon formed by two concentric tubes and a central rod filled with water is studied theoretically and experimentally. The two annuli between the tubes and the rod are joined at the top and bottom and form a flow loop. The middle tube is heated while the outer tube is cooled. In this one-dimensional model equations for continuity, momentum, and energy for steady laminar flow are written and solved numerically. There is reasonably good agreement between the analytically and experimentally determined temperatures and convective velocities in the thermosiphon.