Patent ID: 8176725

Claim:
A gas turbine engine comprising: a fan drive gear system comprising: a turbofan; a fan shaft connected to an inner diameter of the turbofan; and an epicyclic gear system connected to a downstream end of the fan shaft; a low spool connected to the fan drive gear system, the low spool comprising: a rearward-flow low pressure compressor disposed aft of the fan drive gear system; and a forward-flow low pressure turbine disposed aft of the rearward-flow low pressure compressor; a high spool disposed aft of the low spool, the high spool comprising: a forward-flow high pressure turbine disposed aft of the forward-flow low pressure turbine; a combustor disposed aft of the forward-flow high pressure turbine; and a forward-flow high pressure compressor disposed aft of the combustor; a reverse ducting disposed radially outward of the high spool for directing output of the rearward-flow low pressure compressor to the forward-flow high pressure compressor such that the output reverses flow to pass through the high spool; exhaust ducting disposed radially outward of the reverse ducting for receiving exhaust gas from the forward-flow low pressure turbine and fan air from the turbofan: and an intercooling and recuperating heat exchanger mounted adjacent the reverse ducting between the rearward-flow low pressure compressor and the forward-flow high pressure compressor; wherein flow through the engine extends sequentially through the rearward-flow low pressure compressor in a downstream direction, and through the forward-flow high pressure compressor, the combustor, the forward-flow high pressure turbine and the forward-flow low pressure turbine in a forward direction.