Acoustic Flow Sensor Thermal Expansion Compensation
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Solution Overview
Problem
Determining the distribution of temperature, pressure, and velocity in gas turbine engines is challenging due to extreme conditions, and existing methods, such as intrusive probes and optical instruments, face limitations like degradation at high temperatures and uncertainty from thermal expansion.
Innovation Solution
An acoustic temperature and velocity mapping sensor system that compensates for thermal expansion by using acoustic transducers and temperature sensors to accurately measure fluid flow properties, with a processor determining current path lengths and fluid properties based on nominal temperatures and thermal expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If intrusive probes are used to measure fluid flow properties, then measurement capability is provided, but the probes experience degradation at extreme temperatures
Solution Approach 1:
The patent introduces an acoustic wave as an intermediary medium to transfer measurement information from the hot fluid to the sensor without direct contact. The acoustic wave travels through the fluid and interacts with the sensor, allowing temperature and velocity measurements while the sensor remains protected from extreme thermal conditions.
Solution Approach 2:
The patent replaces the mechanical intrusive probe system with an acoustic field-based measurement system. Instead of physically inserting mechanical sensors into the hot fluid, the system uses acoustic waves to probe the fluid properties, eliminating the mechanical contact that causes degradation.
2Reliability
If acoustic transducers are used to measure fluid flow properties, then non-intrusive measurement is achieved, but thermal expansion of chamber walls introduces uncertainty
Solution Approach 1:
The patent implements a feedback mechanism where temperature sensors mounted on the chamber walls continuously monitor thermal expansion, and this information is fed back to the processor. The processor uses this feedback to dynamically adjust and compensate for the path length changes caused by thermal expansion, maintaining measurement accuracy despite temperature variations.
Solution Approach 2:
The patent accounts for changes in physical parameters (specifically path length) due to thermal expansion. By monitoring temperature changes and calculating the corresponding path length variations, the system adjusts its measurements to compensate for these parameter changes, maintaining precision under varying thermal conditions.
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 approach provides high accuracy in characterizing hot fluid flows under extreme conditions by reducing uncertainty caused by thermal expansion, ensuring precise measurements of temperature and velocity distributions in gas turbine engines.
Implementation Method 1
This sensor technology is based on continuously finding the time of flight of acoustic waves accurately across a space of the fluid flow
Implementation Method 2
some uncertainty is introduced into the derivation of fluid flow properties due to thermal expansion of the walls that hold the acoustic transducers and enclose the space of the fluid flow
Data Source
AI summary
Techniques for a chamber, such as gas turbine engine (100), surrounding a heated fluid include a sensor (150) mounted in a first wall (228b, 229b) of the chamber to detect phenomenon inside the chamber and a processor (702). The processor is in electrical communication with the sensor and is configured to receive first data, determine a first temperature of the first wall, determine a current path length, determine properties of the fluid flow, and operate a device based on the properties. First data indicates a value of the phenomenon along a path between the first wall and a different wall of the chamber. The current path length (268b) is based on a nominal path length (268a) and thermal expansion of the first wall due to the first temperature. The property of fluid flow in the chamber is based on the first data and the current path length.