Mechnaism Investigation On Flow And Heat Transfer Of Capillary Pumped Loop In AMTEC

AMTEC（Alkali Metal Thermal to Electric Converter） is a power system, which basedon Beta " Alumina Solid Electrolyte is properties of a good conductor of ions, but a insulatorof electrons, it has a characteristic of high conversion efficiency with no moving parts, and isa promising technology for the space and terrestrial applications. The AMTEC cell power islimited by the cell hot and cold end temperatures, and also limited by the performance ofcapillary pump. Capillary pump flow capacity affect directly on the performance of converterefficiency, and the capillary pump reliability is determined mainly by the thermodynamiclimits where phase change can occur. So it is important to study fluid flow and heat transfer inthe capillary pump.A axisymmetric2D generalized mathematical calculation model was set up, whichincludes coupled heat and mass transfer process in the capillary pump, the Phase FieldMethod is used on tracking liquid-vapor interface and the source terms are added in theContinuity Equation, Momentum Equation and Energy Equation used to simulate theprocesses of phase change and the capillary forces. the pressure field, velocity field andtemperature field can be easily simulated, and the nocontinuous velocity and pressure inliquid-vapor interface can be obtained and solved precisely. With this model, characteristics offluid flow, heat change, and reliability, which reveal operational mechanism of capillary pump,was simulated and analyzed and so on.The simulation results show that, the capillary pump flow performance improve withlager the pore size, porosity, temperature, thermal conductivity of the conduction stud andevaporator material, and decreasing the current and thermal conductivity of transport artery.The evaporation rate of the capillary pump increases with the increasing porosity ofevaporator wick, thermal conductivity of the conduction stud and evaporator material, butdecreases with the increasing thermal conductivity and porosity of transport artery. The poresize has no affect on the evaporation rate and heat efficiency. The evaporator material haslittle affect on the thermal efficiency of capillary pump, but the transport artery material hasobvious affect on the thermal efficiency of capillary pump, the lager thermal conductivity of it,the higher thermal efficiency of capillary pump. The capillary pump critical size decreases with the increasing hot end temperature and current and decreasing porosity, but thecondenser temperature has much smaller affect on it.