High temperature turbomachine

A turbomachine, comprising:

• an electric machine comprising:
• an electric machine housing;
• an electric stator within the housing;
• an electric rotor comprising permanent magnets, the rotor being within the stator and electric machine housing and extending from an end of the electric machine housing;
• and
• a plurality of active magnetic bearing actuators configured to levitate the electric rotor within the stator and provide both radial and axial support;
• and
• a fluid end configured to drive or expand a fluid of 250° C. or higher, the fluid end comprising:
• a fluid end housing coupled to and hermetically sealed to the electric machine housing to define hermetically sealed interior space therein that receives a portion of the fluid;
• and
• an impeller or turbine within the fluid end housing and coupled about an end of the rotor to rotate at the same speed as the rotor, and
• where the electric machine housing comprises a front end face sealed to the outer surface of the rotor by a seal, and the turbomachine comprises a heat shield spaced from the front end face substantially covering the front end face and seal.

A method, comprising:

• operating a fluid end of a turbomachine to drive a 250° C. or hotter working fluid with an impeller or to drive a turbine of the turbomachine with the working fluid;
• rotating a permanent magnet rotor of an electric machine of the turbomachine on an axis within a stator of the electric machine at the same speed as the impeller or turbine, the fluid end having a housing sealed to a housing of the electric machine to define a hermetically sealed space therein that receives a portion of the fluid, the interior of the housing of the fluid end sealed from the interior of the housing of the electric machine;
• levitating the rotor within the stator of the electric machine with a plurality of active magnetic bearing actuators while controlling the axial position of the impeller or turbine;
• and
• receiving a portion of the working fluid that has leaked from the housing of the fluid end into the housing of the electric machine, hermetically sealing the leaked working fluid within the housing of the electric machine, and allowing the leaked working fluid to circulate through axial passages in a cylindrical sleeve residing concentrically within the housing of the electric machine.

A turbomachine, comprising:

• an electric machine comprising a rotor and a stator in a housing;
• a fluid end configured to drive or expand a working fluid of 250° C. or higher, the fluid end comprising an impeller or turbine in a housing, the impeller or turbine coupled to the rotor to rotate at the same speed as the rotor and the housing of the fluid end is hermetically sealed to the housing of the electric machine to define a hermetically sealed space there that is configured to receive a portion of the working fluid and the interior of the housing of the fluid end is sealed from the interior of the housing of the electric machine;
• a sleeve concentrically within the housing of the electric machine and defining axial passages therethrough, the sleeve in contact with and supporting the stator in the housing of the electric machine;
• and
• an active magnetic bearing system supporting the rotor, and
• where when working fluid leaks from the housing of the fluid end into the housing of the electric machine, the leaked working fluid is hermetically sealed within the housing of the electric machine, and where the leaked working fluid in the housing of the electric machine is allowed to circulate in the housing of the electric machine around the stator.