ESP Rotor Assembly With Thrust Washer Support for Thermal Expansion
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Solution Overview
Problem
Existing electric submersible pump (ESP) assemblies face issues with differential thermal expansion and related bearing failures due to varying thermal expansion rates of components, leading to increased loads and potential motor failure.
Innovation Solution
The implementation of a rotor assembly with a hydrodynamic bearing system, including a thrust washer support mechanism that utilizes a support sleeve and concavities to create a hydrodynamic lubricating film, preventing direct contact between the thrust washer and the bushing, thereby managing thermal expansion and reducing wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional bearing system is used in the ESP rotor assembly, then the structure is simple and easy to manufacture, but differential thermal expansion causes increased loads and bearing failures
Solution Approach 1:
A thrust washer support mechanism is introduced as an intermediary component between the rotor assembly and the bearing system. This support mechanism absorbs and manages differential thermal expansion forces, preventing them from being transmitted directly to the bearing, thereby reducing bearing loads and failures while maintaining overall system simplicity
Solution Approach 2:
The bearing system is modified to include a thrust washer support that changes the load distribution parameters. By introducing this additional support structure, the bearing operates under optimized load conditions that account for thermal expansion variations, improving reliability without significantly increasing complexity
2Reliability
If components are rigidly connected in the rotor assembly, then manufacturing and assembly are simplified, but thermal expansion differences lead to increased loads and potential motor failure
Solution Approach 1:
The thrust washer support acts as a mediator between rigidly connected components, allowing controlled movement and expansion while maintaining overall structural integrity. This intermediary element protects the motor from thermal expansion-induced loads without requiring complete redesign of the rotor assembly
Solution Approach 2:
The thrust washer support mechanism provides preemptive cushioning against thermal expansion forces before they can transmit to critical components like the motor. By anticipating and absorbing these forces in advance, the system prevents potential motor failures without adding complex active control mechanisms
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively manages thermal expansion and reduces bearing wear, enhancing the reliability and longevity of ESP assemblies by maintaining proper alignment and reducing frictional forces.
Implementation Method 1
concavities configured to influence flow of lubrication fluid between the bushing and the thrust washer to create a hydrodynamic force against the bushing and the thrust washer when the drive shaft rotates
Implementation Method 2
differential thermal expansion and related bearing failures due to varying thermal expansion rates of components
Data Source
AI summary
An exemplary rotor assembly for an ESP motor can comprise a rotor module concentrically disposed on a drive shaft; a bearing assembly concentrically disposed about the drive shaft in proximity to the rotor module; a thrust washer concentrically disposed about the drive shaft and axially between the bearing assembly and the rotor module; and an axial support flange disposed concentrically about the drive shaft and axially between the thrust washer and the rotor module. In some embodiments, the axial support flange can abut the thrust washer. Disclosed embodiments may reduce dishing of the thrust washer when the motor is in operation, which can be particularly useful in embodiments having concavities formed in an axial face of the bearing bushing or the thrust washer which can influence flow of lubrication fluid between the bushing and the thrust washer to create a hydrodynamic force.