Barrel Centrifugal Compressor Sliding Key Radial Stability
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Solution Overview
Problem
Centrifugal compressors experience unstable vibration and increased leakage at high pressures due to radial movement of the diaphragm and head flange, leading to unbalanced pressure distribution and fluid force, which affects the efficiency and stability of the rotor.
Innovation Solution
The implementation of sliding key grooves and keys on the inner and outer peripheral surfaces of the diaphragm and head flange, respectively, to prevent radial movement and maintain a consistent gap size in the labyrinth seal, thereby stabilizing the rotor operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the tip gap of the labyrinth seal is reduced to avoid tooth contact, then the stability of the rotor is improved, but the leakage increases which lowers efficiency
Solution Approach 1:
The sliding keys are installed in advance in the sliding key grooves of the casing before the diaphragm and head flange are assembled. This preliminary action prevents radial movement of the diaphragm and head flange, thereby maintaining a consistent tip gap of the labyrinth seal teeth and avoiding both tooth contact and excessive leakage during operation.
2Reliability
If the tip gap of the labyrinth seal is enlarged to prevent tooth contact, then the stability of the rotor is improved, but the leakage increases which lowers efficiency
Solution Approach 1:
The sliding keys are installed in advance in the sliding key grooves of the casing before the diaphragm and head flange are assembled. This preliminary action prevents radial movement of the diaphragm and head flange, thereby maintaining a consistent tip gap of the labyrinth seal teeth and avoiding both tooth contact and excessive leakage during operation.
3Reliability
If sliding keys are added to prevent radial movement, then the stability of the rotor is improved, but the device complexity increases
Solution Approach 1:
Sliding keys are introduced as intermediary elements that fit into sliding key grooves on the casing inner peripheral surface. These sliding keys act as mediators to prevent radial movement of the diaphragm and head flange, thereby maintaining seal gap consistency without requiring fundamental redesign of the compressor structure.
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 solution effectively suppresses the increase of unstable fluid force and contact between the rotor and labyrinth seal teeth, ensuring stable rotor operation even at high pressures while minimizing leakage and maintaining efficiency.
Implementation Method 1
sliding keys are provided in the key grooves... to prevent the movement of the diaphragm and the head flange in the radial direction with respect to the casing
Implementation Method 2
owing to a pressure loss of a fluid flowing through tip gaps of the teeth, the leakage of the fluid is decreased
Implementation Method 3
compresses a gas sucked through a suction port by the rotation of impellers
Data Source
AI summary
In a centrifugal compressor, for the purpose of preventing the positions of a diaphragm and a head flange in a radial direction from moving with respect to a casing, preventing the unstable vibration of the rotor and enabling an efficient and stable operation even on high-pressure conditions, there is provided a barrel-shaped centrifugal compressor including a casing, a diaphragm located in the casing to define a flow channel, and a head flange attached to the end of the casing by a shear key, wherein in the inner peripheral surface of the casing and the outer peripheral surface of abutment portions of the diaphragm and the head flange in which they are abutted on the inner peripheral surface of the casing, sliding key grooves which are vertical to the surfaces are provided at least two portions in a peripheral direction, and sliding keys are provided in the key grooves.