Abo Bibliothek: Guest

ISSN Online: 2377-424X

ISBN Print: 0-89116-909-1

International Heat Transfer Conference 9
August, 19-24, 1990 , Jerusalem, Israel

INVESTIGATION OF HEAT TRANSFER CHARACTERISTICS OF A CRITICALLY FILLED TWO-PHASE CLOSED THERMOSYPHON BY TRANSIENT OPERATION

Get access (open in a dialog) DOI: 10.1615/IHTC9.4150
pages 413-418

Abstrakt

The transient behaviour of a two-phase closed thermosyphon up to the pool boiling crisis is investigated. An analytical model, based on a control-volume formulation, is developed to predict the transient response of the whole apparatus when increasing temperature at the heating zone is imposed. Measurements, taken from five parallel operating thermosyphons, each of them critically filled with trifluorochloromethane (R13), agree well with the analytical prediction. Additionally, the Zuber−Helmholtz analysis of the pool boiling crisis is modified analytically, taking into account the pool geometry and the growing influence of a thermo-mechanical effect of boiling when the pressure approaches the critical state. The physical effect is verified at both steady state and transient operation. Therefore various transient operation modes are simulated up to the boiling crisis. If thermosyphons are filled subcritically, the pool level decreases and film boiling dry-out may thereby occur.