Dynamic Pressure Sensor Nesting for Combustion Instability Detection
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Solution Overview
Problem
DLN combustors in gas turbines face challenges with thermo-acoustic combustion instability, requiring effective detection and control methods to prevent structural vibrations and system failure, where existing technologies struggle to accurately measure flame characteristics for stable operation.
Innovation Solution
A system comprising a dynamic pressure sensor with a wave guide and wave guide tube, operatively connected to a combustion can, and a fine wire temperature sensor disposed through the wave guide tube, allowing for simultaneous measurement of pressure and temperature data within the combustion chamber to detect and manage combustion instability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If DLN combustors are used to reduce NOx emissions through lean premixed combustion, then emissions are reduced, but combustion instability occurs leading to structural vibrations and potential system failure
Solution Approach 1:
The patent implements preliminary detection of combustion instabilities using dynamic pressure sensors that monitor pressure oscillations before they escalate into harmful structural vibrations. By detecting early signs of instability through acoustic pressure fluctuations, the system can take corrective action preemptively, maintaining reliable operation of DLN combustors while preserving their emission reduction benefits
Solution Approach 2:
The patent employs feedback mechanisms where dynamic pressure sensors continuously monitor combustion chamber pressure oscillations and provide real-time data about combustion instability. This feedback loop enables the control system to adjust combustion parameters dynamically, stabilizing the lean premixed combustion process and preventing the development of harmful vibrations while maintaining low NOx emissions
2Reliability
If dynamic pressure sensors are installed to detect combustion instability, then early detection is enabled, but device complexity increases
Solution Approach 1:
The patent integrates dynamic pressure sensors that serve multiple functions: detecting combustion instability through pressure oscillation monitoring, measuring acoustic characteristics of the combustion chamber, and providing data for both diagnostic and control purposes. This multi-functionality reduces the need for separate specialized sensors, thereby limiting the increase in device complexity while maintaining reliable instability detection
Solution Approach 2:
The patent uses the combustion chamber's existing acoustic field as an intermediary carrier of instability information. Dynamic pressure sensors detect natural pressure oscillations that inherently exist in the combustion chamber, converting physical acoustic phenomena into measurable electrical signals. This approach leverages the natural physics of the system rather than requiring complex external measurement apparatus, thereby detecting instability with relatively simple sensor technology
3Measurement precision
If temperature sensors are used to measure flame temperature for combustion control, then flame characteristics can be monitored, but sensor installation becomes more complex in DLN combustors
Solution Approach 1:
The patent nests the temperature sensor within the protective structure of the dynamic pressure sensor assembly. The temperature sensor is positioned concentrically or coaxially within the pressure sensor's waveguide or housing, allowing both sensors to share the same installation path and structural support. This nested arrangement enables temperature measurement capability while utilizing the existing pressure sensor infrastructure, thereby limiting additional installation complexity
Solution Approach 2:
The patent combines the installation of dynamic pressure sensors and temperature sensors into a single integrated sensor assembly or mounting structure. By merging the installation processes and structural requirements of both sensor types, the system achieves both pressure oscillation monitoring and flame temperature measurement through coordinated sensor placement, reducing the overall installation complexity compared to separate independent installations
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 enables early detection of combustion instabilities, allowing for adjustments to ensure smooth operation, reducing the risk of system failure and potentially lowering operating costs by directly measuring environmental conditions in multi-combustor turbines.
Implementation Method 1
dynamic pressure sensors are often utilized in gas turbine DLN combustion chambers to detect initial combustion instability
Implementation Method 2
the determination of flame temperature has historically been attributed great importance in the field of combustion technology
Implementation Method 3
a wave guide and wave guide tube... allowing for simultaneous measurement of pressure and temperature data within the combustion chamber
Data Source
AI summary
A system and method disclosed may include a dynamic pressure sensor or probe having a wave guide and wave guide tube and a temperature sensor disposed therethrough in order to optimally install and position the temperature sensor to measure combustor flame characteristics. The dynamic pressure sensor is preferably positioned or mounted on the outer casing of the combustor. By taking advantage of the placement of an existing dynamic pressure sensor, a temperature sensor—for instance a fine wire temperature probe—can be disposed through the interior of the dynamic pressure sensor so that combustion flame characteristics can be measured near the combustion liner.