Heat Pipe Fundamentals
The modern heat pipe technology was originated from the Los Alamos Scientific Laboratory in 1963. A good description of the history of the heat pipe technology can be found in an early article published by Yale Eastman (currently a Director of ACT) in Scientific American in May 1968. A typical tubular heat pipe is illustrated below.
It is a vacuum tight device consisting of a working fluid and a wick structure. The heat input vaporizes the liquid working fluid inside the wick in the evaporator section. The vapor, carrying the latent heat of vaporization, flows towards the cooler condenser section. In the condenser, the vapor condenses and gives up its latent heat. The condensed liquid returns to the evaporator through the wick structure by capillary action. The phase change process and two-phase flow circulation continue as long as the temperature gradient between the evaporator and condenser is maintained.
