Gas Turbine Case Heating Element for Bleed Air Duct Ice Prevention

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Solution Overview

Problem

Conventional gas turbine engine cases face issues with foreign material accumulation in bleed air ducts, which can block airflow and cause material to be recirculated into the compressor, particularly during hail or ice ingestion, leading to inefficiencies and potential damage.

Innovation Solution

A gas turbine engine case with a core body and structural member that includes a resistive heating element, which can be positioned within a bore or overlay surfaces, and a control system to adjust heating based on flight conditions to prevent ice and hail accumulation on the bleed air duct surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If bleed air ducts are used to extract foreign material from the core flow path, then foreign material removal is improved, but ice and hail accumulation on duct surfaces blocks airflow and causes material recirculation

Engineering Contradiction:
Improveforeign material extractionVSAvoidice and hail accumulation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The heating element is activated before foreign material extraction to pre-heat the bleed air duct surfaces, preventing ice and hail accumulation before it can block the ducts. This preliminary thermal action ensures the ducts remain clear for effective foreign material removal.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The heating element, which consumes energy, converts the harmful effect of cold temperatures that cause ice accumulation into a beneficial effect by maintaining duct surface temperatures above freezing, thereby preventing blockages and ensuring continuous operational reliability.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Reliability

If heating elements are added to prevent ice accumulation, then airflow reliability is improved, but device complexity increases

Engineering Contradiction:
Improveairflow continuityVSAvoidheating system integration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The heating element serves multiple functions: it prevents ice and hail accumulation on duct surfaces, maintains airflow continuity, and can be integrated with existing engine thermal management systems. This multi-functionality reduces the need for separate dedicated anti-icing systems.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The heating element is designed to be self-regulating through thermal feedback from the duct surfaces, automatically adjusting its operation to maintain optimal temperatures without requiring complex external control systems, thereby reducing overall device complexity.

Inventive Principle:
Principle #25Self-service

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 effectively prevents ice and hail accumulation on the bleed air duct surfaces, ensuring efficient airflow and reducing the risk of blockages, thereby maintaining engine efficiency and performance during hazardous conditions.

Implementation Method 1

a resistive heating element connects to the core body and is in thermal communication with the structural member

Methodology Applied
Scientific EffectResistive heating: Joule Heating

Implementation Method 2

the heating element is seated in the case bore... in thermal communication with a core flow path-facing surface of the structural member

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3620617B1Core case heating for gas turbine engines
Publication Date: 2022.10.26 RTX CORP
  • EP3620617B1 patent drawingFigure 1
  • EP3620617B1 patent drawingFigure 2
  • EP3620617B1 patent drawingFigure 3~4

AI summary

A case for a gas turbine engine includes a core body. The core body defines a longitudinally extending core flow path, a laterally extending bleed air duct coupling the core flow path in fluid communication with the external environment, and a structural member spanning the bleed air duct. A heating element is connected to the core body and is in thermal communication with the structural member.