Sensor Assembly Ice Prevention via Internal Bleed Air Impingement
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Solution Overview
Problem
Existing temperature and pressure sensor assemblies in aircraft gas turbine engines face challenges in preventing ice buildup on leading edges, particularly during idle decent conditions, where conventional methods like electrical heating or external bleed air washing may be inefficient or ineffective.
Innovation Solution
A sensor assembly design featuring a housing with a leading edge portion and a tube system where compressor bleed air is directed to impinge against an interior wall section, providing efficient heating to prevent ice buildup, and including a sensor for measuring temperature and pressure in fluid communication with the compressor/fan inlet flow path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrical heaters are used to heat the leading and trailing edges of the housing, then ice buildup is prevented, but energy consumption increases and heating efficiency decreases
Solution Approach 1:
The patent uses pneumatic heating by directing compressor bleed air (hot gas) through channels in the housing to heat the leading and trailing edges. This replaces electrical heating elements with a pneumatic/thermal system that uses existing engine resources (compressor bleed air) to achieve ice prevention, thereby reducing energy consumption and improving heating efficiency.
2Reliability
If compressor bleed air is used to wash over the exterior of the housing, then ice buildup is prevented, but heating efficiency is insufficient compared to direct impingement
Solution Approach 1:
Instead of washing heated air over the exterior surface of the housing (conventional approach), the patent inverts the approach by directing the heated compressor bleed air to impinge directly against the interior wall sections of the leading and trailing edges. This internal impingement method transfers heat more efficiently to the critical surfaces, significantly improving heating efficiency while maintaining reliable ice prevention.
3Ease of manufacture
If a monolithic housing is used, then manufacturing is simpler, but ice accretion cannot be segmented into smaller pieces
Solution Approach 1:
The patent incorporates internal segmentation features within the monolithic housing structure. The housing includes internally defined channels and wall sections that segment the interior space. When ice forms on these segmented interior surfaces, it breaks into smaller pieces that are less harmful to downstream engine components, while the housing itself remains a single manufactured piece for ease of production.
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 effectively prevents ice accumulation by utilizing impinging heated compressor bleed air, ensuring reliable operation and accurate measurements by maintaining the sensor assembly free from ice, even under ambient conditions conducive to ice formation.
Implementation Method 1
The distal portion is located in the housing and includes at least one air outlet hole. The at-least-one air outlet hole is spaced apart from the interior wall section and is aligned to direct at least some of the compressor bleed air flow to impinge against the interior wall section
Implementation Method 2
use of impinging compressor bleed air on an interior wall section of a leading edge portion is a more efficient heating method to prevent ice buildup
Data Source
AI summary
A sensor assembly includes a housing and a tube. The housing has a first leading edge portion which is capable of being located in a compressor/fan inlet flow path and which includes an interior wall section. The tube has a proximal portion including an air inlet which is adapted to receive a compressor bleed air flow and a distal portion which is located in the housing and which includes at least one air outlet hole. The hole is spaced apart from the interior wall section and is aligned to direct at least some compressor bleed air flow to impinge against the interior wall section. The housing includes an opening which receives air from the flow path when the housing is located in the flow path, wherein the opening is adapted for fluid communication with a sensor, and wherein the sensor measures at least one of air temperature and air pressure.