Tip turbine engine with multiple fan and turbine stages

Abstract

A tip turbine engine () provides first and second turbines () rotatably driven by a combustor () generating a high-energy gas stream. The first turbine () is mounted at an outer periphery of a first fan (), such that the first fan is rotatably driven by the first turbine (). The second turbine () is mounted at an outer periphery of a second fan (), and is rotatably driven by the high-energy gas stream. In one embodiment, the first turbine () rotatably drives a plurality of stages of first compressor blades () in an axial compressor () in a first rotational direction, while the second turbine () rotatably drives a plurality of stages of second compressor blades () in the axial compressor () in a second rotational direction opposite the first. By rotatably driving alternating stages of compressor blades in opposite directions, the efficiency of the axial compressor () is increased and/or the number of stages of compressor blades can be reduced. Other variations are described in additional embodiments.