A capillary wick for use in capillary evaporators has properties that prevent
nucleation
inside the body of the wick, resulting in suppression of back-conduction of heat
from vapor channels to the liquid reservoir. Use of a central liquid flow channel
in the wick is eliminated, and pore size in the wick is chosen to maximize available
pressure for fluid pumping, while preventing nucleation in the wick body. The wick
is embodied with different geometries, including cylindrical and flat. A flat capillary
evaporator has substantially planar heat input surfaces for convenient mating to
planar heat sources. The flat capillary evaporator is capable of being used with
working fluids having high vapor pressures (i.e., greater that 10 psia). To contain
the pressure of the vaporized working fluid, the opposed planar plates of the evaporator
are brazed or sintered to opposing sides of a metal wick. Additionally, a terrestrial
loop heat pipe and a loop heat pipe having overall flat geometry are disclosed.
