Compressor Surge Prevention via Shaft Vibration Control
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Solution Overview
Problem
Chiller systems experience compressor surge due to high compression ratios, leading to refrigerant backflow and damage, with existing solutions failing to prevent or mitigate damage effectively.
Innovation Solution
A compressor system that includes vibration measuring sensors and controllers to detect abnormal vibration frequencies in the discharge passage, adjusting motor operating frequencies and shaft vibrations to prevent surge by performing alternating surge avoidance operations until the vibration frequency returns to normal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the compression ratio of the compressor is increased to improve cooling capacity, then the cooling performance is improved, but surge occurs causing refrigerant backflow and compressor damage
Solution Approach 1:
The vibration sensor detects abnormal vibrations in the discharge passage before surge actually occurs, and the controller performs surge avoidance operations (changing motor operating frequency or vibrating the rotating shaft) in advance to prevent surge. This preliminary detection and intervention prevents the harmful backflow and compressor damage before they can occur, while allowing the compressor to operate at high compression ratios for improved cooling capacity.
2Reliability
If control operations are performed after surge occurs to remove the surge, then the surge condition is corrected, but damage has already been caused to the compressor
Solution Approach 1:
The system applies preliminary anti-action by detecting the precursor signs of surge (abnormal vibration frequencies in the discharge passage) and counteracting them before the harmful effects manifest. The controller changes the motor operating frequency or vibrates the rotating shaft in response to detected abnormal vibrations, creating a counter-effect that prevents surge from developing into damaging backflow conditions.
3Reliability
If vibration measuring sensors and control systems are added to detect and prevent surge, then compressor protection is improved, but device complexity increases
Solution Approach 1:
The vibration sensor acts as an intermediary element that indirectly detects surge conditions by measuring vibration frequencies in the discharge passage, rather than requiring direct measurement of refrigerant flow or pressure. This intermediary approach provides reliable surge detection with relatively simple sensor placement and signal processing, improving compressor protection without proportionally increasing system complexity.
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
Prevents compressor damage by anticipating and mitigating surge events, reducing the force required to adjust the rotating shaft position and minimizing thrust bearing volume and current usage.
Implementation Method 1
a vibration measuring sensor configured to measure a vibration frequency of the discharge passage
Implementation Method 2
a motor configured to rotate the impellers; a controller configured to control an operating frequency of the motor
Implementation Method 3
at least two thrust bearings limiting vibration of the rotating shaft in an axial direction
Data Source
AI summary
A compressor that vibrates a rotary shaft or changes an operating frequency of a motor, in response to a vibration frequency of a discharge passage falling outside of a normal range. The compressor may include one or more impeller configured to draw in and compress refrigerant; a motor configured to rotate the one or more impeller; a rotary shaft, to which the one or more impeller and the motor are coupled; at least two thrust bearings that limit vibration of the rotary shaft; a vibration measuring sensor configured to measure a vibration frequency of a discharge passage; and a controller configured to control the at least two thrust bearings based on the vibration frequency. Upon determining that the vibration frequency falls outside of a normal vibration frequency range, the controller controls the at least two thrust bearings to vibrate the rotary shaft a predetermined number of times.