Heat Pipes

Surface tension is an important phenomenon in heat pipes. Heat pipes undergo various heat transfer limitations, depending on the working fluid, the wick structure, the dimensions of the heat pipes, and the operational temperatures. Heat pipes can be limited in one of four ways: capillary limitation, sonic limitation, entrainment limitation, and boiling limitation. The temperature drop between the evaporator and condenser of a heat pipe is of particular interest to the designer of heat pipe thermal control system for electronics. The variable conductance heat pipe, sometimes called the gas-controlled or gas-loaded heat pipe, has a unique feature that sets it apart from other types of heat pipe. Loop heat pipes are capable of transferring heat for distances up to several meters at any orientation in the gravity field, or several tens of meters in a horizontal position.