Compressor Instability Prediction via Skew Analysis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for predicting instability in compressors, such as axial and radial compressors, fail to provide an early warning for impending surge limit exceedance, leading to costly failures during testing and potential damage in operational environments.
Innovation Solution
A method and device that determine an instability indicator by operating the compressor through varying flow mass flux states, using time-resolved pressure measurements from sensors upstream of the rotor stage to calculate the skew parameter, identifying algebraic sign changes in the curve profile, which indicate potential instability before the surge limit is reached.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the surge limit is determined by running the compressor until instability occurs, then the surge limit can be identified, but costly total failures and structural damage occur
Solution Approach 1:
The patent applies preliminary action by determining the surge limit through skew analysis of pressure fluctuations before the compressor actually reaches instability. The method calculates the skew of pressure fluctuations at different operating points and identifies the surge limit by detecting when the skew becomes zero or changes sign, allowing the surge limit to be determined without actually exceeding it and causing damage
Solution Approach 2:
The patent replaces the mechanical approach of running the compressor until failure with a computational method. Instead of physically pushing the compressor to instability, the system uses pressure sensor data and skew calculations to predict and identify the surge limit, substituting mechanical trial-and-error with mathematical analysis
2Reliability
If traditional pressure measurement methods are used, then the system is simple, but early warning of compressor instability cannot be provided
Solution Approach 1:
The patent introduces skew as an intermediary parameter that mediates between raw pressure measurements and instability prediction. The skew calculation transforms complex pressure fluctuation patterns into a single meaningful metric that directly indicates proximity to the surge limit, serving as a bridge between measurement and prediction
Solution Approach 2:
The system implements feedback by continuously monitoring pressure fluctuations, calculating skew values, and using this information to predict impending instability. The method provides real-time feedback about the compressor's proximity to the surge limit, allowing operators to take corrective action before instability occurs
Data Source
AI summary
The invention relates to a method for determining an indicator for a prediction of an instability in a compressor, which is designed as an axial or radial compressor, having the following steps: operating a compressor designed as an axial or radial compressor in operating states, which differ by different values of a characteristic parameter for a flow mass flux of the compressor, wherein the operating states are run through at decreasing flow mass fluxes; determining the values of the characteristic value for the flow mass flux for the operating states; detecting time-resolved pressure measurement values when running through the operating states by means of a pressure sensor, which is arranged in a housing of the compressor, upstream adjacent to an entrance plane of a rotor stage determining the skew for the operating states and determining an indicator for an instability of the compressor, if an algebraic sign change of the curve rise is determined for a curve profile of the skew over the characteristic parameter for the flow mass flux for the operating states. The invention further relates to the use of the method and a device for determining an indicator for a prediction of an instability in an compressor.