Centrifugal Compressor Annular Groove Surging Suppression
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Solution Overview
Problem
Centrifugal compressors face operational instability due to surging caused by reverse fluid flow at low flow rates, limiting their operation range, and existing casing treatments only partially address this issue.
Innovation Solution
The design incorporates an annular groove on the casing's inner surface that communicates with an annular chamber, forming a curved line over the entire circumference to disperse increased pressure from the impeller-accommodating portion, with the most upstream point positioned to face the impeller's vane, enhancing the surging suppression effect and extending the compressor's operation range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a groove is provided on the casing wall surface to recirculate fluid upstream of the impeller, then surging is suppressed, but the operation range extension is limited
Solution Approach 1:
The invention transitions from a two-dimensional groove on the casing wall to a three-dimensional annular chamber with curved groove configuration. The annular chamber extends axially and radially, creating a volumetric space that interacts with the impeller-accommodating portion in multiple dimensions, thereby enhancing surging suppression effectiveness and extending the stable operation range more effectively than conventional two-dimensional groove treatments.
Solution Approach 2:
The invention changes the geometric parameters of the casing treatment by forming an annular chamber with specific axial and radial dimensions, and configuring the groove as a curved line with predetermined amplitude. These parameter changes create optimal flow interaction characteristics that improve surging suppression across a broader operation range compared to conventional groove designs.
2Reliability
If the groove is formed as a curved line with cyclical changes, then pressure dispersion is improved, but the manufacturing complexity increases
Solution Approach 1:
The groove is configured as a curved line that cyclically changes with a predetermined amplitude, creating a periodic pattern around the annular chamber. This periodic configuration optimizes pressure dispersion by creating regular flow interaction zones, while the repetitive nature of the pattern allows for efficient manufacturing using standardized forming processes.
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 configuration effectively disperses high pressure into an annular chamber, improving surging suppression and expanding the compressor's operational range without fluid recirculation, maintaining higher pressure ratios at low flow rates.
Implementation Method 1
the groove communicates the impeller-accommodating portion and the annular chamber with each other... even when the pressure of part of the impeller-accommodating portion increases, the increased pressure is dispersed into the annular chamber through the groove
Data Source
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AI summary
The centrifugal compressor (1) includes: an impeller (3); and a casing (2) accommodating the impeller (3). The casing (2) includes: an inlet (6); an impeller-accommodating portion (14) in which the impeller (3) is disposed; an annular flow passageway (5) formed around the impeller (3); an outlet (9) communicating with the annular flow passageway (5); and an annular chamber (11) formed around at least one of the inlet (6) and the impeller-accommodating portion (14). An inner circumferential surface (2a) of the casing (2) facing the impeller-accommodating portion (14) is provided with a groove (12) which communicates the impeller-accommodating portion (14) and the annular chamber (11) with each other and which is formed over the entire circumference of the inner circumferential surface (2a). In addition, the annular chamber (11) communicates with another space only through the groove (12).