Gas Turbine Plenum Pressure Sensor Placement
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Solution Overview
Problem
Current gas turbine assemblies fail to reliably detect pressure fluctuations, particularly in specific frequency bandwidths, which can lead to reduced power output and combustor component integrity issues due to acoustic oscillations during lean premix combustion.
Innovation Solution
A gas turbine assembly with pressure sensors strategically placed between the outlet diffuser and outer casing of the plenum, enhancing monitoring sensitivity across all relevant frequency bands without affecting engine efficiency or air consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressure sensors are placed in conventional locations within the combustor, then the monitoring system is simple to implement, but the detection reliability and sensitivity to acoustic oscillations are insufficient
Solution Approach 1:
The patent transitions the pressure sensor placement from the traditional internal combustor location to the plenum chamber, representing a spatial dimension change. This relocation allows the sensor to detect pressure fluctuations in a region with different acoustic characteristics, thereby improving detection reliability for acoustic oscillations without adding complex sensor arrangements
Solution Approach 2:
The plenum chamber acts as an intermediary space between the compressor outlet and combustor inlet. By placing the pressure sensor in this intermediate region, the system can monitor pressure fluctuations that are indicative of acoustic oscillations without directly exposing the sensor to the harsh combustor environment, thus improving reliability while maintaining implementation simplicity
2Measurement precision
If pressure sensors are positioned to maximize sensitivity to acoustic oscillations, then the monitoring accuracy improves, but the device complexity and installation difficulty increase
Solution Approach 1:
The patent applies local quality by specifically targeting the plenum chamber region for sensor placement, where pressure fluctuations contain valuable information about acoustic oscillations. This localized approach enhances measurement precision for detecting harmful pressure variations while avoiding the need for complex multi-sensor arrangements throughout the entire combustor system
3Difficulty of detecting and measuring
If the monitoring system is made highly sensitive to detect all frequency bandwidths, then the detection capability improves, but the system complexity and potential interference with engine operation increase
Solution Approach 1:
The plenum chamber serves as an intermediary measurement location that naturally provides broad frequency detection capability. Pressure fluctuations from acoustic oscillations across different frequency bands propagate through the plenum, allowing a single sensor to detect a wide range of frequencies without requiring complex sensor arrays or signal processing systems
Solution Approach 2:
By placing the pressure sensor in the plenum chamber, the same sensor position can detect acoustic oscillations across multiple frequency bandwidths simultaneously. This universal detection capability eliminates the need for multiple specialized sensors or complex monitoring systems, thereby improving detection capability while maintaining system simplicity
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 solution enables reliable detection of pressure fluctuations, improving engine tuning and operation, and preventing destructive acoustic oscillations, thus maintaining structural integrity and efficiency.
Implementation Method 1
acoustic oscillations may be triggered spontaneously (here and hereinafter identified with the term 'humming' typically used in the sector of reference), which are destructive to the structural integrity of the combustor
Data Source
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AI summary
A Gas turbine assembly comprises: • a compressor (3) configured to compress air; the compressor (3) extending along a longitudinal axis and being provided with an outlet diffuser (26) and with a compressor casing (9a); • a plenum (30), which is a closed volume delimited at least by an outer casing (31) coupled to the compressor casing (9a) and by the outlet diffuser (26); the outlet diffuser (26) being designed to discharge the compressed air into the plenum (30); • a combustor (4) partially arranged in the plenum (30); • at least one pressure sensor (7; 7a; 7b; 7c) facing an area of the plenum (30) comprised between the outer casing (31) and the outlet diffuser (26).