Multistage turbomachine with embedded electric motors
AssigneeNuovo Pignone S.p.A.
InventorsLorenzo Bergamini, Marco Cipriani
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Abstract
A multistage turbomachine is disclosed, comprising a casing with a fluid inlet and a fluid outlet and a plurality of stages arranged in the casing. A flow path extends from the fluid inlet to the fluid outlet through the sequentially arranged stages. Each stage is comprised of a rotating impeller and an electric motor embedded in the casing and arranged for rotating the impeller at a controlled rotary speed. Each electric motor comprises a motor rotor, arranged on the impeller and integrally rotating therewith, and a motor stator stationarily arranged in the casing. Pairs of sequentially arranged impellers are configured for rotation in opposite directions.
Claims20
A multistage turbomachine, comprising:
- a casing with a fluid inlet and a fluid outlet;
- and
- a plurality of stages sequentially arranged in the casing with a first stage positioned adjacent the fluid inlet, a last stage positioned adjacent the fluid outlet and at least one intermediate stage positioned between the first stage and the last stage;
- wherein:
- a flow path extends from the fluid inlet to the fluid outlet through the sequentially arranged stages;
- each stage is comprised of a rotating impeller and an electric motor embedded in the casing and arranged for rotating the impeller at a controlled rotary speed;
- each electric motor comprises a motor rotor arranged on the impeller and integrally rotating therewith and a motor stator stationarily arranged in the casing;
- pairs of sequentially arranged impellers are configured for rotation in opposite directions;
- and
- a control arrangement configured and arranged to rotate each impeller at a rotational speed which can vary from one impeller to the other,
- wherein the control arrangement controls the rotary speed of the stages to be identical at a set gas volume fraction (GVF) %;
- if the GVF % becomes lower than the set GVF %, the control arrangement controls the rotary speed of the first stage to be decreased and the rotary speed of the at least one intermediate stage to be increased;
- and if the GVF % becomes higher than the set GVF %, the control arrangement controls the rotary speed of the first stage to be increased and the rotary speed of the at least one intermediate stage to be decreased.
A method for boosting the pressure of a variable-compressibility fluid, the method comprising:
- sequentially arranging a plurality of impellers for rotation in a casing of a turbomachine with a first impeller positioned adjacent a fluid inlet of the casing, a last impeller positioned adjacent a fluid outlet of the casing and at least one intermediate impeller positioned between the first impeller and the last impeller;
- rotating the sequentially arranged impellers in opposite directions with a respective electric motor embedded in the casing;
- processing a fluid through the impellers;
- boosting a fluid pressure from a suction pressure to a delivery pressure;
- controlling at least one operating parameter of the embedded motors such that impellers rotate at different rotational speeds;
- controlling the rotary speed of the impellers to be identical at a set gas volume fraction (GVF) %;
- controlling the rotary speed of the first stage to be decreased and the rotary speed of the at least one intermediate stage to be increased if the GVF % becomes lower than the set GVF %;
- and
- controlling the rotary speed of the first stage to be increased and the rotary speed of the at least one intermediate stage to be decreased if the GVF % becomes higher than the set GVF %.
Dependencies are inferred from the claim text.