Abstract: The operational behavior of small-scale flat-plate type capillary pumped loop (CPL) at high heat fluxes was analyzed.The total pressure loss along the loop and maximum capillary pressure of the evaporator wick for different working fluids were obtained.The analysis results show that ammonia working fluid had better performance and higher capillary limit,and capillary limit was affected significantly by vapor line radius and working fluid density.The working fluid transmission coefficient was introduced as an important criterion for choosing working fluid.The numerical model of porous wick,metal wall and fluid region of CPL evaporator were established, and the entire evaporator is solved with SIMPLE algorithm as a conjugate problem.The numerical results are obtained and the effect of evaporator metal side wall conduction on the working limit of system is discussed.The side wall effect working limit existed in the small-scale flat-plate type CPL evaporator is introduced.The obtained results are useful for the design of small-scale flat-plate type CPL evaporator.

Key words: Side wall effect, Heat transfer limit, Porous wick, Working medium transmission coefficient, Small-scale flat-plate type capillary pumped loop, Small vehicle