Variable Area Diffuser Vane Containment and Alignment
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Solution Overview
Problem
Variable area diffusers in compressed air systems face challenges with structural deflection and debris containment under high stresses, particularly during rotor failure, which can lead to binding conditions and safety hazards.
Innovation Solution
A design featuring a mounting plate that supports a backing plate and shroud with pivot pins in a slip fit relationship, and protrusions and bolts extending through vanes to maintain parallel alignment and contain debris, ensuring improved operation and containment during loading and potential failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the diffuser structure is subjected to high stresses during high-speed rotor operation, then the compressor can operate at high speeds to increase productivity, but the structure adjacent to the vanes deflects causing binding conditions that compromise operation
Solution Approach 1:
The diffuser structure is segmented into multiple independent components: vanes mounted on a backing plate, which is separately mounted to the housing. This segmentation allows each component to deflect independently under load, preventing binding conditions while maintaining high-speed operation capability
Solution Approach 2:
A mounting plate is introduced as an intermediary component between the housing and the backing plate. This mounting plate absorbs and distributes the stresses, allowing the backing plate and vanes to maintain their relative positions and clearances even under high operational loads
2Ease of operation
If the vanes are contained within the diffuser structure during normal operation, then the diffuser can maintain its flow control function, but in the event of rotor failure the vanes cannot contain debris creating safety hazards
Solution Approach 1:
The containment solution extends into a new dimension by adding protrusions that extend axially from the backing plate through the vanes. This axial dimension provides an additional barrier for debris containment while not interfering with the radial flow control function of the vanes
3Reliability
If the vanes are securely mounted to prevent deflection during operation, then the diffuser operation is improved, but the structure becomes more complex requiring additional mounting components
Solution Approach 1:
The mounting function is merged into a single integrated mounting plate that performs multiple functions: supporting the backing plate, providing pivot pin mounting locations, and incorporating protrusions for debris containment. This consolidation reduces the number of separate components while maintaining reliable vane positioning
Data Source
AI summary
A diffuser includes multiple vanes rotatable about pivot pins between multiple positions. A mounting plate supports a backing plate. The vanes are arranged between the backing plate and the shroud. The pivot pins are in a slip fit relationship with the backing plate, vanes and shroud and are threadingly received by bosses in the mounting plate. The mounting plate and pivot pin arrangement better enables the backing plate and shroud to remain parallel with one another during deflection of the backing plate and/or shroud. Structure, such as integral protrusions and/or bolts, extend from between the backing plate and shroud through apertures in the vanes to better contain the vanes in the event of a catastrophic failure.