Electric submersible pump rotor assembly with hydrodynamic bearing

An electric submersible pump for pumping fluid in a wellbore, comprising:

• a centrifugal pump;
• a drive shaft configured to transmit torque to the centrifugal pump;
• a journal sleeve concentrically disposed about and rotationally fixed to the drive shaft;
• a bushing concentrically disposed about the journal sleeve;
• a stator concentrically disposed about the bushing;
• and
• a thrust washer encircling the drive shaft,
• wherein concavities are formed in an axial face of the bushing or an axial face of the thrust washer,
• wherein the axial face of the bushing is disposed proximate to the axial face of the thrust washer,
• wherein a depth of the concavities is less than 0.2 mm,
• wherein a radius of the concavities is greater than 200 mm, and
• wherein the concavities are configured to influence flow of lubrication fluid between the bushing and the thrust washer to create a hydrodynamic film between the bushing and the thrust washer when the drive shaft rotates.

A rotor assembly for an electric submersible pump, comprising:

• a drive shaft;
• a journal sleeve concentrically disposed about and rotationally fixed to the drive shaft;
• a bushing concentrically disposed about the journal sleeve;
• and
• a component encircling the drive shaft,
• wherein concavities are formed in an axial face of the bushing or an axial face of the component,
• wherein the axial face of the bushing is disposed proximate to the axial face of the component, and
• wherein the concavities are configured to influence flow of lubrication fluid between the bushing and the component to create a hydrodynamic force of 5 to 5,000 N against the bushing and the component when the drive shaft rotates.