Compressor Shaft Position Control to Reduce Impeller Contact and Wear
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Solution Overview
Problem
Compressor inefficiencies arise due to misalignment and contact between the impeller and housing, leading to reduced efficiency and structural integrity issues.
Innovation Solution
A system and method for monitoring and adjusting the position of the impeller relative to the compressor housing using a controller and thrust bearing to maintain a predetermined distance, ensuring alignment with the diffuser passage and minimizing contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the impeller is positioned closer to the housing to improve compression efficiency, then the compression ratio increases, but the risk of contact and structural damage increases
Solution Approach 1:
The patent employs active thrust bearing control to dynamically adjust the impeller position along the axial direction. The thrust bearing can move the impeller closer to the housing during high-performance operations to improve compression efficiency, then retract it when contact risk increases. This dynamic positioning resolves the contradiction by making the system adaptable rather than fixed, allowing optimal balance between efficiency and reliability based on real-time operating conditions.
2Ease of manufacture
If the impeller position is fixed to simplify the system, then manufacturing and maintenance are easier, but the ability to optimize performance under varying conditions is reduced
Solution Approach 1:
The control system automatically monitors impeller position using sensors and adjusts the thrust bearing position without requiring manual intervention. The system self-regulates to maintain optimal clearance between the impeller and housing based on detected position data, eliminating the need for complex manual adjustment mechanisms while preserving adaptability to varying operating conditions.
3Reliability
If the clearance between impeller and housing is increased to prevent contact, then reliability improves, but compression efficiency and power output decrease
Solution Approach 1:
The patent implements a feedback control loop where sensors continuously detect the impeller position and housing clearance, and the control system adjusts the thrust bearing position based on this feedback. When the clearance approaches a critical threshold that would reduce compression power, the system automatically reduces the clearance to maintain optimal performance. Conversely, when reliability concerns arise, the system increases clearance. This closed-loop feedback mechanism dynamically balances reliability and power output.
Data Source
AI summary
A heating, ventilation, air conditioning, and refrigeration (HVAC&R) system includes a compressor having a housing, a shaft disposed within and extending through the housing, and an impeller coupled to the shaft, where the shaft is configured to rotate relative to the housing and about an axis to rotate the impeller. The HVAC&R system also includes a controller configured to receive data indicative of a distance from a shroud of the impeller to the housing and to adjust a position of the shaft along the axis based on a comparison of the distance from the shroud of the impeller to the housing with a predetermined value.