Dry-out characteristics of heat pipes

Dryout characteristics of heat pipes having capillary wicks were analyzed by a simple model on the basis of the effect of axial heat conduction. It was found that the profiles of axial temperature distribution in the wall for heat transfer rates over the critical point were dependent upon the value of a dimensionless parameter Y-asterisk representing the degree of axial heat conduction compared to radial heat conduction. Namely, for heat pipes of larger Y-asterisk (greater than 10,000), the temperature increases at the end point of the heating section. But, for heat pipes of small Y-asterisk (less than 100), the temperature at the point does not rise so highly if dryout proceeds. From that viewpoint, the significance of a critical heat flux by capillary pumping limit was investigated.