Centrifugal Compressor Movable Member Friction Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The movable member in centrifugal compressors experiences increased friction and load when driven due to air flowing backward, causing surging, which affects the efficiency of the throttling mechanism.
Innovation Solution
A centrifugal compressor design with a housing featuring an intake flow path, a compressor impeller, an accommodation chamber, and a movable member with contacting and non-contacting portions on the accommodation chamber surface, reducing friction and load by directing air flow to minimize contact with the movable member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the movable member protrudes into the intake flow path to block backward-flowing air and inhibit surging, then surging is prevented, but the frictional force between the movable member and the compressor housing wall increases, causing increased load on the throttling mechanism
Solution Approach 1:
The accommodation chamber opposing surface is divided into a contacting portion and a non-contacting portion. The non-contacting portion allows air to pass through without contacting the movable member, reducing frictional force and load on the throttling mechanism. The contacting portion is positioned at the radially innermost area to maintain effective surge inhibition. This local differentiation resolves the contradiction by reducing load in non-critical areas while maintaining reliability in critical areas.
2Reliability
If the movable member is pressed against the wall surface by backward-flowing air, then the movable member effectively blocks air flow to prevent surging, but the frictional force increases, making the movable member harder to drive
Solution Approach 1:
By creating a non-contacting portion on the accommodation chamber opposing surface, the patent reduces the contact area between the movable member and the housing wall. This local reduction in contact area decreases frictional force, making the movable member easier to drive while maintaining surge prevention capability through the strategically positioned contacting portion at the radially innermost area.
3Reliability
If the movable member blocks the intake flow path to prevent surging, then air flow backward is inhibited, but the frictional resistance increases, requiring more power to operate the throttling mechanism
Solution Approach 1:
The differentiation of the accommodation chamber opposing surface into contacting and non-contacting portions reduces the overall frictional resistance by minimizing contact area. The non-contacting portion allows air to flow without generating friction, while the contacting portion at the radially innermost area maintains the necessary blocking function. This reduces the power required to drive the movable member while preserving surge inhibition reliability.
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
This design reduces the load required to drive the movable member, enhancing the operational efficiency of the centrifugal compressor by minimizing friction and preventing surging.
Implementation Method 1
the non-contacting portion may communicate with the intake flow path
Data Source
AI summary
A centrifugal compressor includes: a housing including an intake flow path; a compressor impeller disposed in the intake flow path; an accommodation chamber formed upstream of the compressor impeller in the housing; a movable member disposed in the accommodation chamber and configured to be movable between a retracted position where the movable member is retracted from the intake flow path and a protruding position where the movable member protrudes from the accommodation chamber into the intake flow path, the protruding position being located closer to the intake flow path with respect to the retracted position, and a contacting portion and a non-contacting portion provided on an accommodation chamber opposing surface of the accommodation chamber, the accommodation chamber opposing surface being positioned upstream of the movable member, the contacting portion being contactable with the movable member, the non-contacting portion being non-contactable with the movable member.