Centrifugal Compressor Stage Surging Prevention via Diffusion Area Adjustment
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Solution Overview
Problem
Multi-stage centrifugal compressors are prone to surging when the running load is reduced, leading to decreased airflow velocity, which can cause airflow reversal and damage to the compressor, affecting performance, noise, vibration, and reliability.
Innovation Solution
A centrifugal compressor design with multiple stages of compression units, each equipped with a diffusion cavity adjustment device featuring a movable member that changes the flow area of the diffusion cavity, connected via transmission rods and a reset mechanism to prevent surging by adjusting the flow area based on load conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single movable diffusion cavity adjustment device is used in a multi-stage centrifugal compressor, then the surging phenomenon is improved at the first stage, but the surging phenomenon cannot be overcome at other stages
Solution Approach 1:
The patent divides the single diffusion cavity adjustment device into multiple independent adjustment devices, with each stage of the multi-stage centrifugal compressor having its own movable diffusion cavity adjustment device. This segmentation allows each stage to independently adjust its diffusion cavity passage area to prevent surging at that specific stage, thereby solving the problem where a single device could only protect one stage while leaving other stages vulnerable to surging.
2Reliability
If the passage area of the diffusion cavity is decreased to increase flow velocity, then surging is prevented, but device complexity increases due to multiple adjustment devices
Solution Approach 1:
The patent combines multiple movable diffusion cavity adjustment devices into a coordinated system where each device is controlled by its own inlet guide blade. The control mechanisms are integrated such that when the running load is reduced, all adjustment devices work together to decrease their respective diffusion cavity passage areas, increasing flow velocity at each stage and preventing surging throughout the entire multi-stage compressor without requiring overly complex independent control systems.
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
Effectively reduces the likelihood of surging across all stages, improving compressor efficiency, reliability, and reducing noise and vibration by dynamically adjusting the diffusion cavity area in response to changing load conditions.
Implementation Method 1
a diffusion cavity; and a diffusion cavity adjustment device, the diffusion cavity adjustment device comprising a movable member configured to change a flow area of the diffusion cavity
Implementation Method 2
a transmission rod, the transmission rod being in drive connection with the corresponding movable member
Data Source
Figure 1
Figure 2~3
AI summary
The invention discloses a centrifugal compressor. The centrifugal compressor includes multiple stages of compression units which are communicated in sequence. Each stage of compression unit includes a diffusion cavity (1) and a diffusion adjustment device, wherein the diffusion adjustment device includes a movable member (21) configured to change a radial flow area of the diffusion cavity (1) provided in correspondence thereto, the movable member (21) being movably provided in an axial direction of the centrifugal compressor. The invention also discloses a centrifugal unit having the centrifugal compressor. The movable member of each stage of compression unit of the centrifugal compressor changes the radial flow area of the diffusion cavity of this stage of compression unit, thereby effectively reducing the possibility of surging.