The present disclosure provides assemblies for cooling a liquid fuel cartridge unit within a combustor head end. In one embodiment, the cooling is accomplished passively as air from the head end air plenum is directed into a cooling channel radially outward of a liquid fuel delivery conduit. In another embodiment, the cooling of the liquid fuel cartridge unit is accomplished actively as air is directed through a first air flow conduit radially inward of the liquid fuel delivery conduit and then redirected through a second air flow conduit radially outward of the liquid fuel delivery conduit.