Dynamic model of heat and mass transfer in an unsaturated porous wick of capillary pumped loop

This paper presents a numerical study of a Capillary Pumped Loop evaporator. A two-dimensional unsteady mathematical model of a flat evaporator is developed to simulate heat and mass transfer in unsaturated porous wick with phase change. The liquid–vapor phase change inside the porous wick is described by Langmuir's law. The governing equations are solved by the Finite Element Method. The results are presented then for a sintered nickel wick and methanol as a working fluid. The heat flux required to the transition from the all-liquid wick to the vapor–liquid wick is calculated. The dynamic and thermodynamic behavior of the working fluid in the capillary structure are discussed in this paper. - Highlights: • We develop an unsteady model of two phase flow in porous wick with phase change. • We describe the heat and mass transfer inside the CPL evaporator. • We study the dynamic growth of the vapor pocket inside the porous wick. • The transition from the all liquid wick to the vapor–liquid wick is examined. • Porous wick with large porosity and conductivity reduces the parasitic flux