A ceramic porous wick is proposed in this book as an alternative to wicks made of sintered metal and plastic materials for applications in LHPs and CPLs. A theoretical and experimental analysis is presented. First, the heat and mass transfer in a flat capillary evaporator formed by a single or double-layered porous wick is analyzed. The wick has a shape of a flat disc and it is assembled between the liquid and vapor channels. An external heat input is applied in the upper surface of the wick, where the working fluid evaporates. The mass and heat transfer are modeled using the mass and energy...