Stability analysis of a closed thermosyphon model
Abstract
Closed twophase thermosyphon stability is analyzed as a function of the heat input, liquid filling, viscosity, density, capillary number and twophase flow Grashof number. It is shown that for small liquid fillings there is a onetoone correspondence between the heat input and the corresponding steadystate solution, and that for larger fillings there is a stable and an unstable solution possible for each heat input. A turning point is indicated at the maximum heat input at which one of the eigenvalues of the linear stability analysis is zero. It is found that the steady operation of the thermosyphon is insensitive to the vaportoliquid viscosity ratio and the thermosyphon length, and very sensitive to vaportoliquid density ratio. Upper limits for the heat input are found for large fillings near the steadystate operating conditions. It is also shown that a linear analysis grossly underestimates the transient behavior of the thermosyphon behavior.
 Publication:

Applied Mathematics Mechanics English Edition
 Pub Date:
 February 1986
 Bibcode:
 1986ApMaM..10...61R
 Keywords:

 Flow Stability;
 Heat Pipes;
 Thermosiphons;
 Two Phase Flow;
 Grashof Number;
 Steady State;
 Transient Response;
 Viscosity;
 Fluid Mechanics and Heat Transfer