Variable Diffuser Vane Actuation via Rotatable Pennies
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Solution Overview
Problem
Centrifugal compressors face reduced efficiency and stall margin when operating off their design point, necessitating improved diffuser area variation to enhance performance across varying operating conditions.
Innovation Solution
A variable diffuser system comprising a passage between opposing faces of a hub and a tip, with rotatable pennies coupled to vanes, allowing continuous adjustment of vane orientation through actuation, thereby optimizing fluid flow and stall margin during off-design conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a centrifugal compressor is designed to operate at maximum efficiency and minimum adequate surge margin at the design point, then efficiency and stall margin are optimized at the design point, but efficiency and stall margin are reduced when operating off the design point
Solution Approach 1:
The patent applies the dynamics principle by making the diffuser vanes adjustable and movable rather than fixed. The diffuser vane angle can be dynamically changed based on operating conditions, allowing the compressor to maintain optimal performance across a wider range of flow rates. This is achieved through mechanisms such as bellcranks, linkages, or actuators that enable the diffuser vanes to pivot or translate, thereby adapting the diffuser geometry to match varying operational demands and prevent stall conditions during off-design operation.
2Productivity
If the diffuser area is varied to improve efficiency and stall margin during off-design operation, then performance is improved, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the diffuser into multiple discrete vanes rather than using a continuous or monolithic structure. Each vane can be independently actuated or grouped into segments that move together, allowing for controlled area variation. This segmentation enables the diffuser to adapt its geometry through the movement of individual vanes or groups of vanes, providing flexibility in area adjustment while maintaining structural manageability and reducing overall system complexity compared to a fully continuous variable geometry design.
Solution Approach 2:
The patent employs intermediary mechanisms such as bellcranks, linkages, or actuators that serve as mediators between the control system and the diffuser vanes. These intermediaries translate control inputs into precise vane movements, enabling area variation without requiring direct complex actuation of each vane. The intermediary mechanisms simplify the control architecture by providing mechanical advantage, coordinated movement, or simplified actuation paths, thereby reducing the overall device complexity while achieving the desired variable area functionality.
Data Source
AI summary
A variable diffuser comprises a passage, at least two vanes disposed within the passage, and at least two pennies. The passage is defined between opposing disk faces of a hub and a tip. Each of the vanes comprises a body having a leading edge and a trailing edge. The body extends between the hub face and the disk face. Each of the pennies is coupled to a respective vane body near an edge of the penny and an actuator. Rotation of at least one penny changes the orientation of the respective vane relative to the hub face.