MATHEMATICAL-MODELING AND ANALYSIS OF HEAT PIPE START-UP FROM THE FROZEN STATE

The start-up process of a frozen heat pipe is described and a complete mathematical model for the start-up of the frozen heat pipe is developed based on the existing experimental data. The model is simplified and solved numerically. The twodimensional transient model for the wall and wick is coupled with the onedimensional transient model for the vapor flow when vaporization and condensation occur at the interface. A parametric study is performed to examine the effect of the boundary specification at the surface of the outer wall on the successful start-up from the frozen state. For successful start-up, the boundary specification at the outer wall surface must melt the working substance in the condenser before dryout takes place in the evaporator. © 1990 by ASME.