Embodiments of a heat transfer apparatus, and related methods, involve a radial array of blades including a plurality of blades arranged about a central portion defining an entrance flow path, the plurality of blades defining a first flow path therebetween, a first heat source in thermal communication with the blades, and a drive system for driving a first fluid into the central portion through the entrance flow path and out through the first flow path between adjacent blades whereby heat is transferred from the first heat source to the first fluid flowing within the first flow path.