Gas Turbine Engine Electric Machine Cooling Heat Exchanger
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Solution Overview
Problem
Conventional gas turbine engines face performance issues due to the use of bypass air or compressor offtakes as cooling mediums, leading to reduced specific thrust and increased specific fuel consumption, as well as reduced surge margin.
Innovation Solution
A turbofan gas turbine engine design with a specific fan axis angle and electric machine sizing that allows for a more compact engine configuration, incorporating a first electric machine positioned downstream of the fan assembly and connected to the turbine module, and a heat exchanger module positioned in the inlet duct to efficiently manage cooling and reduce engine length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If bypass air or compressor offtake is used as cooling medium in heat exchanger, then cooling function is provided, but specific thrust is reduced and specific fuel consumption increases
Solution Approach 1:
The patent extracts the cooling function from the main engine airflow path by using a separate air intake system. The heat exchanger receives cooling air from an independent source rather than from bypass air or compressor offtake, thereby separating the cooling requirement from the propulsive airflow and avoiding thrust penalties.
Solution Approach 2:
The patent implements a multi-functional air intake system that serves both engine operation and heat exchanger cooling requirements. The separate air intake provides a universal air supply that can fulfill both the combustion air needs and the cooling air needs without compromising engine performance.
2Temperature
If bypass air or compressor offtake is used as cooling medium, then cooling is achieved, but surge margin is reduced
Solution Approach 1:
The patent extracts the cooling air supply from the engine's internal airflow paths and provides it from an independent external source. This separation ensures that the heat exchanger cooling requirement does not interfere with the engine's surge margin or compressor operating characteristics.
3Ease of manufacture
If conventional engine configuration is used, then standard packaging is achieved, but engine length is excessive for easy installation
Solution Approach 1:
The patent reconfigures the engine layout by introducing a specific fan axis angle (11-20 degrees) relative to the engine centerline. This angular orientation allows the fan assembly to be positioned more compactly, reducing the overall engine length in the axial direction while maintaining all necessary functional clearances and airflow paths.
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 design results in a more compact and efficient engine with reduced propulsive efficiency losses and improved packaging, enabling easier installation and operation while maintaining effective heat energy rejection.
Implementation Method 1
a heat exchanger module positioned in the inlet duct to efficiently manage cooling and reduce engine length
Data Source
AI summary
A gas turbine engine for an aircraft includes, in axial flow sequence, a compressor module, a combustor module, and a turbine module, with a first electric machine being rotationally connected to the turbine module. The first electrical machine is configured to generate a total electrical power PEM1 (W), and the gas turbine engine is configured to generate a total shaft power PSHAFT (W); and a ratio R of:R=(Total Shaft Power=PSHAFT)(Total Electrical Power Generated=PEM1)is in a range of between 0.005 and 0.020.