ABSTRACT
In the design of heat pipes, it is important to establish that heat transport will take place at the required rate without encountering limits on heat transport capability. These limits can arise from the cessation of capillary pumping, the attainment of sonic velocity in the heat pipe vapor, entrainment of the heat pipe liquid by its vapor, or the onset of boiling in the heat pipe liquid. Loss of capillary pumping, entrainment of the heat pipe liquid, or boiling of the liquid can lead to dryout of the heat pipe wick, overheating, and possibly destruction of the heat pipe if the heat input is not rapidly terminated. Although the attainment of sonic velocity also represents a limiting heat transport rate, this limit is not inherently destructive in character. If the heat transport rate should exceed the calculated capillary pumping limit, any resulting partial dryout would reduce the effective condenser area for the transfer of heat to an adjacent heat sink.
