Modeling of a Loop Heat Pipe for Ground and Space Conditions

Copyright © 2005 SAE International This paper presents a mathematical model of a LHP, where its results were compared with experimental test results and the LHP behavior was predicted for Space conditions. In the LHP condenser, the condensate film thickness in the tube is determined by the solution of the conjugate equations of energy, momentum and mass balance in the control volume. Evaporator and compensation chamber are both described by a few transient nodes with generalized key parameters, whose values were adjusted by test results. Experimental LHP consists of cylindrical stainless steel evaporator with an integral compensation chamber, where the primary wick is of micropore UHMW polyethylene and the condenser is an aluminum plate, with acetone as the working fluid. The tests conditions have been reproduced in the mathematical model and its parameters were adjusted using the measured temperatures. The model was applied to predict the LHP behavior for Space conditions, corresponding to the circular low Earth equatorial orbit