Compressor with counter-rotating blade rows

A compressor section of a gas turbine engine, the compressor section comprising a booster compressor and a second compressor located downstream of the booster compressor, the second compressor comprising:

• an upstream portion comprising:
• at least one stage of stator vanes;
• and
• at least one stage of blades that is configured to rotate about an axial centerline of the compressor section, wherein the at least one stage of stator vanes and the at least one stage of blades are in an alternating arrangement along an axial direction of the gas turbine engine;
• and
• a downstream portion disposed immediately adjacent to and downstream along the axial direction from the upstream portion, the downstream portion comprising:
• a first set of rotating blade rows disposed along the axial centerline of the compressor section;
• a second set of rotating blade rows, wherein the first and second sets of rotating blade rows are in an alternating arrangement along the axial direction of the gas turbine engine, wherein the first and second sets of rotating blade rows are in a counter-rotating arrangement;
• a first shaft disposed to rotate about the axial centerline of the compressor section, wherein the first shaft is connected to and drives the at least one stage of blades of the upstream portion and the first set of rotating blade rows of the downstream portion;
• a second shaft disposed to rotate about the axial centerline of the compressor section, wherein the second shaft rotates in an opposite direction from the first shaft, wherein rotation of the second shaft drives rotation of the second set of rotating blade rows of the downstream portion;
• a booster shaft disposed to rotate about the axial centerline of the compressor section;
• a gearbox operably coupled to the booster shaft, wherein the gearbox is disposed to drive rotation of the booster shaft, and wherein the gearbox is also operably coupled to the first shaft and disposed to receive torque from the first shaft;
• and
• a booster compressor disposed upstream from the compressor section, wherein the booster compressor comprises a rotor stage that is operably coupled to and is driven by the booster shaft.