Fully controllable heat pipe containing a short electro-osmotic pumping section

It is pointed out that an electro-osmotic heat pipe (EOHP) is basically a varible conductance heat pipe for which the control properties are realized by the incorporation of a short electro-osmotic pumping section. This section, the 'EO-plug,' controls the liquid flow in the heat pipe wick system and, therefore, the flow rate supplied to the heat pipe evaporator. The underlying theory and the equations governing EOHP performance follow in straightforward fashion from combining heat pipe theory and electro-osmotic considerations. Theoretical considerations result in the definition of two new figures of merit: the electro-osmotic figure of merit, which compares electro-osmotic transport with capillary transport, and the transport capability reduction factor, which represents the flow reducing resistance caused by the EO-plug. Together with the classical heat pipe numbers (liquid transport number, wick number, and wicking height), these figures of merit make it possible to compare EOHP working fluids, plug configurations, and EOHP performance.