Stability maps for rectangular circulation loops

This study aims to define a methodology for the construction of stability maps of rectangular natural circulation loop. The interest. for these maps derives from their-ability to present in synthetic form. the results of stability ana lysis. In fact, the proposed methodology, is based on the linear stability analysis around equilibrium points of a high order nonlinear mathematical model describing the dynamical behaviour of the non-dimensional flow velocity and temperature inside the loop. Imposed heat flux at the loop walls has been assumed at the boundaries; in particular, it has been-considered that the fluid is heated and cooled during its passage in the, horizontal sections, respectively,at bottom and top of the loop, where-as the vertical legs are supposed adiabatic. Hence, the stability analysis was performed considering the effect of the variation of the-modified Grashof number, Gr(m), for a wide range of loop geometrical configurations, assuming various. aspect ratios (ratio of the vertical to the horizontal, length of the tube) and inner tube diameters. (C) 2003 Elsevier Science-Ltd. All rights reserved.