Transient thermohydraulic heat pipe modeling
Abstract
Many space based reactor designs employ heat pipes as a means of conveying heat. In these designs, thermal radiation is the principle means for rejecting waste heat from the reactor system, making it desirable to operate at high temperatures. Lithium is generally the working fluid of choice as it undergoes a liquidvapor transformation at the preferred operating temperature. The nature of remote startup, restart, and reaction to threats necessitates an accurate, detailed transient model of the heat pipe operation. A model is outlined of the vapor core region of the heat pipe which is part of a large model of the entire heat pipe thermal response. The vapor core is modeled using the area averaged NavierStokes equations in one dimension, which take into account the effects of mass, energy and momentum transfer. The core model is single phase (gaseous), but contains two components: lithium gas and a noncondensible vapor. The vapor core model consists of the continuity equations for the mixture and noncondensible, as well as mixture equations for internal energy and momentum.
 Publication:

Space Nuclear Power Systems
 Pub Date:
 1987
 Bibcode:
 1987snps.symp..407H
 Keywords:

 Heat Pipes;
 Mathematical Models;
 Radiative Heat Transfer;
 Thermohydraulics;
 Transient Response;
 Vapors;
 Energy Transfer;
 Heat Radiators;
 Mass Transfer;
 Momentum Transfer;
 NavierStokes Equation;
 Space Power Reactors;
 Fluid Mechanics and Heat Transfer