Grooved NTE Bearings for Axial Thrust Control in Pumps
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Solution Overview
Problem
Existing thrust bearings in centrifugal fluid pumps, such as those used in aircraft thermal management systems, struggle to efficiently balance and support axial thrusts at varying rotational speeds, leading to potential damage and reduced operational efficiency due to unbalanced axial loads and oscillating movements of the impeller shaft.
Innovation Solution
Implementing a bearing system with negative thermal expansion (NTE) coatings in grooves to create a gap between pump components, reducing axial movement and frictional energy losses, and using a thrust disc with thrust pads to support axial thrusts, thereby stabilizing the impeller shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional thrust bearings are used to support axial thrusts in centrifugal pumps, then the bearing structure can provide basic support, but the bearing cannot efficiently balance axial thrusts at varying rotational speeds, leading to unbalanced axial loads and oscillating movements
Solution Approach 1:
The patent applies parameter changes by incorporating NTE materials that change their dimensional parameters (expand or contract) in response to temperature variations caused by different rotational speeds. This allows the bearing to automatically adjust its geometry to maintain optimal clearance and load distribution across varying operating conditions, resolving the contradiction between reliable axial thrust support and adaptability to speed variations.
Solution Approach 2:
The patent uses composite materials by integrating NTE materials into the bearing structure, creating a composite bearing system that combines traditional bearing materials with NTE materials. This composite structure enables the bearing to exhibit both the load-bearing properties of traditional materials and the adaptive dimensional changes of NTE materials, simultaneously achieving reliable axial thrust support and adaptability to varying rotational speeds.
2Device complexity
If the bearing operates without NTE materials, then the structure is simpler, but axial movement and frictional energy losses increase, reducing operational efficiency
Solution Approach 1:
The NTE materials change their dimensional parameters with temperature, automatically adjusting the bearing clearance to optimize lubrication film formation and reduce friction. This dynamic parameter adjustment reduces frictional energy losses without requiring complex control systems, achieving energy efficiency with minimal added complexity.
Solution Approach 2:
The NTE materials provide self-service by automatically adjusting the bearing geometry in response to temperature changes from different operating conditions. This self-adjusting mechanism optimizes lubrication and reduces friction without external control, minimizing energy losses while adding only the NTE material component to the bearing structure.
3Loss of energy
If NTE materials are added to the bearing, then axial movement and frictional losses are reduced, but the manufacturing process becomes more complex
Solution Approach 1:
The integration of NTE materials into the bearing structure creates a composite material system that can be manufactured using established composite material techniques. This approach reduces frictional losses while managing manufacturing complexity through proven composite material processing methods.
Solution Approach 2:
The NTE materials are applied locally to specific regions of the bearing where temperature-induced dimensional changes are most beneficial for reducing friction. This localized application minimizes the overall manufacturing complexity by incorporating NTE materials only where needed rather than throughout the entire bearing structure.
4Duration of action of stationary object
If the bearing uses NTE materials in grooves, then the lifespan and performance are improved, but the manufacturing precision requirements increase
Solution Approach 1:
The grooves containing NTE materials are created in specific local regions of the bearing where they provide maximum benefit for extending bearing lifespan. By concentrating the precision manufacturing requirements to localized groove formations rather than the entire bearing surface, the overall manufacturing precision challenge is managed more effectively.
Solution Approach 2:
The integration of NTE materials into grooves creates a composite structure that extends bearing lifespan through improved lubrication and reduced friction. The groove geometry and NTE material placement can be optimized to achieve the desired lifespan extension while managing manufacturing precision requirements through proven composite material fabrication techniques.
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 reduces axial movement and frictional losses, enhances operational efficiency, and increases the time between maintenance services by effectively balancing axial thrusts, thus improving the lifespan and performance of the pump.
Implementation Method 1
a negative thermal expansion (NTE) material positioned in the groove, the NTE material at least partially filling the groove... the NTE material shrinks in response to the impeller shaft moving relative to at least one of the radial bearing, windage heating, or contact with moving surrounding thermal fluid
Data Source
AI summary
A bearing having a bearing surface with a groove, the bearing positioned adjacent to a shaft, the groove facing the shaft, and a negative thermal expansion (NTE) material positioned in the groove, the NTE material at least partially filling the groove.