Centrifugal Compressor Diffuser Adjustment for Surge Control
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Solution Overview
Problem
Centrifugal compressors experience surge phenomena and noise issues at low load conditions due to the conventional design of the inlet guide vane, which affects their operational efficiency and reliability.
Innovation Solution
A centrifugal compressor design that adjusts the flow-path width of the diffuser using a diffuser-adjusting assembly, eliminating the need for an inlet guide vane and incorporating a driving assembly to transform rotational motion into linear motion, thereby avoiding surge and reducing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the open degree of the inlet guide vane is adjusted to control capacity at low load conditions, then the surge phenomenon can be avoided, but notorious noises are generated
Solution Approach 1:
The patent removes the inlet guide vane from the system entirely and replaces it with a diffuser-adjusting assembly that adjusts the diffuser vane angle instead. This extraction of the noisy component (inlet guide vane) while maintaining the surge avoidance function through an alternative mechanism (diffuser adjustment) directly resolves the contradiction between avoiding surge and reducing noise.
Solution Approach 2:
The patent introduces a diffuser-adjusting assembly as an intermediary mechanism between the drive shaft and the diffuser vane. This assembly includes a driving ring with drive-rod slots and pin tracks that convert rotational motion into linear motion to adjust the diffuser vane angle, providing a noise-free alternative to the conventional inlet guide vane while maintaining surge control capability.
2Adaptability or versatility
If the inlet guide vane is disposed at the impeller to control flow, then capacity regulation is achieved, but noise is generated
Solution Approach 1:
The patent extracts the inlet guide vane from its conventional position at the impeller inlet and relocates the flow control function to the diffuser section. The diffuser-adjusting assembly controls the diffuser vane angle to regulate gas flow, achieving capacity regulation without the noise associated with inlet guide vane operation.
Solution Approach 2:
Instead of controlling flow at the inlet (conventional approach), the patent inverts the control location to the diffuser section downstream. By adjusting the diffuser vane angle rather than the inlet guide vane angle, the system achieves flow control and capacity regulation from a different location in the flow path, eliminating the noise problem.
3Reliability
If the diffuser flow-path width is adjusted to prevent surge, then operational reliability is improved, but device complexity increases
Solution Approach 1:
The patent merges the drive-rod slot and pin track functions into a single integrated driving ring structure. The driving ring simultaneously provides the drive-rod slots for linear motion transmission and the pin tracks for rotational motion conversion, combining multiple functional elements into one compact component that reduces overall structural complexity while maintaining surge prevention capability.
Solution Approach 2:
The driving ring serves multiple functions: it converts rotational motion from the drive shaft into linear motion of the driving rods, provides guidance for the pins to control rotational movement, and transmits force to adjust the diffuser vane angle. This multi-functionality reduces the number of separate components needed, simplifying the overall structure while achieving reliable surge prevention.
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
The design allows the compressor to operate silently and efficiently at low load conditions by adjusting the diffuser flow-path width, preventing surge and minimizing noise, thus enhancing operational reliability and reducing potential damage.
Implementation Method 1
incorporating a driving assembly to transform rotational motion into linear motion
Implementation Method 2
a device that utilizes an impeller to work on gas in a centrifugal manner so as to boost the pressure and the velocity of the gas
Data Source
AI summary
A centrifugal compressor includes a volute base block, a volute cover plate, an impeller, a diffuser-adjusting assembly, a radial constraint assembly, an axial constraint assembly and a driving assembly. A diffuser and a connected volute are formed between the cover plate and the base block. The impeller discharges gas to the centrifugal compressor through the diffuser and the volute. The diffuser adjustment assembly includes a driving ring, a driving rod, a pin and a diffuser ring. The radial constraint assembly is disposed on an inner circumference surface of the driving ring. The axial constraint assembly on an outer circumference surface of the driving ring is located between the top and bottom portions. The drive assembly is to rotate the driving ring. When the driving ring rotates, the pin slides along the pin track, and the driving rod displaces the diffuser ring to adjust a flow-path width of the diffuser.