A thermal management loop system may include an accumulator, an evaporator in fluid receiving communication with the accumulator, a condenser in fluid receiving communication with the evaporator, and a rotary separator in fluid receiving communication with the condenser. Gas exiting the rotary separator may recirculate back to the condenser and liquid exiting the rotary separator may flow to the accumulator. The thermal management loop system may be a dual-mode system and thus may be operable in a powered-pump mode or a passive-capillary mode.