Airfoil Sensor Layout for Icing-Resistant Temperature Measurement
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Solution Overview
Problem
Existing pressure and temperature sensors in gas turbine engines are prone to malfunction in icing conditions due to ice and super-cooled moisture, which can interrupt sensor operation and introduce measurement errors, and existing heating methods to counter ice can further introduce errors.
Innovation Solution
The sensors are designed with a pressure channel that shunts heated air away from the temperature probe, using an expansion chamber to slow air velocity and melt entrained ice, and an insulating cavity to thermally separate the heater element from the temperature probe, along with an ice accretion feature to redirect ice accretion away from critical areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heating is employed to counter ice crystal ingestion and ice accretion, then ice protection is improved, but temperature measurement accuracy deteriorates due to measurement error introduced by the heater element
Solution Approach 1:
The sensor is divided into functionally independent segments: a heater element for ice protection and a temperature probe for measurement, separated by an insulating cavity. This segmentation allows the heater to operate without thermally affecting the temperature probe, resolving the contradiction between ice protection and measurement accuracy.
Solution Approach 2:
An insulating cavity acts as a thermal intermediary between the heater element and the temperature probe. This intermediary structure blocks heat transfer from the heater to the probe, enabling the heater to provide ice protection while preventing it from introducing measurement errors into the temperature probe.
2Measurement precision
If the temperature probe is positioned within the sensor to measure temperature, then temperature sensing capability is improved, but the probe becomes vulnerable to ice ingestion and accretion that interrupt operation
Solution Approach 1:
The heater element is positioned upstream and operates preliminarily to prevent ice accretion before it can reach the temperature probe. The ice accretion feature and heated air flow create a protective thermal environment that preemptively melts ice, ensuring the temperature probe remains clear and operational.
Solution Approach 2:
The insulating cavity serves as a protective intermediary that shields the temperature probe from ice particles and accretion while allowing it to measure the temperature of clean, heated air that has passed through the expansion chamber.
3Reliability
If a heater element is positioned within the sensor to prevent ice accretion, then ice protection is improved, but thermal communication with the temperature probe introduces measurement error
Solution Approach 1:
The sensor structure is segmented into a heater element zone and a temperature probe zone, separated by an insulating cavity. This physical and thermal segmentation ensures that the heater element can provide ice protection without its heat being communicated to the temperature probe, thereby maintaining measurement accuracy.
Solution Approach 2:
Different regions of the sensor are given different thermal properties: the heater element region is thermally active for ice protection, while the temperature probe region is thermally isolated through the insulating cavity to maintain measurement accuracy. The insulating cavity creates a local thermal barrier that preserves the distinct functional qualities of each zone.
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 design minimizes the interference of ice and super-cooled moisture, ensuring accurate pressure and temperature measurements by limiting thermal communication between the heater element and temperature probe, and reducing the likelihood of ice-induced anomalies.
Implementation Method 1
an expansion chamber to slow air velocity and melt entrained ice
Implementation Method 2
an insulating cavity to thermally separate the heater element from the temperature probe
Implementation Method 3
heating can be employed to counter to ice crystal ingestion and/or ice accretion
Implementation Method 4
a pressure channel that shunts heated air away from the temperature probe
Data Source
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AI summary
A sensor includes an airfoil body (104), a heater element (134), and a temperature probe (158). The airfoil body (104) defines a sensor axis, an insulating cavity (172), and extends between a leading edge and a trailing edge of the airfoil body. The heater element (134)extends axially within the airfoil body and is positioned between the leading edge and the trailing edge of the airfoil body. The temperature probe extends axially within the airfoil body, is positioned between the heater element and the trailing edge of the airfoil body, and is separated from the heater element by the insulating cavity to limit thermal communication between the temperature probe and the heater element. Gas turbine engines, methods of making sensors, and methods of thermally separating temperature probes and heater elements in sensors are also described.