Modulated Air-Cooled Heat Exchanger for Cruise Drag Reduction
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Solution Overview
Problem
Hybrid electric systems in gas turbine engines face challenges in managing system waste heat efficiently without incurring significant drag losses due to the increased size of heat exchangers, which is not viable for low air-flow operating conditions.
Innovation Solution
A modulated air-cooled heat exchanger with an inlet door that dynamically controls airflow through a heat exchanger using a modulation control actuator, allowing for adjustable airflow modulation to optimize heat transfer and reduce nacelle drag losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the size of heat exchanger is increased to reject system waste heat in low air-flow operating conditions, then the heat rejection capacity is improved, but the drag losses at cruise are increased
Solution Approach 1:
The inlet door is made movable and adjustable, transitioning from a fixed-size heat exchanger to a dynamically configurable one. The door can be positioned at different angles to modulate the effective inlet area, allowing the heat exchanger to adapt its size to match varying thermal management requirements across different operating conditions, thereby rejecting adequate heat without incurring excessive drag losses during cruise
Solution Approach 2:
The effective inlet area parameter of the heat exchanger is made variable through the adjustable inlet door mechanism. By changing the inlet area parameter dynamically based on operating conditions (fully open for maximum heat rejection, partially closed for reduced drag), the system optimizes the trade-off between heat rejection capacity and drag losses without requiring a permanently oversized heat exchanger
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 reduces nacelle drag losses at cruise while maintaining minimal weight impact by adaptively tailoring airflow to mission needs, ensuring efficient thermal management.
Implementation Method 1
The heat exchanger is configured to transfer heat from a thermal management system to the airflow
Data Source
AI summary
A gas turbine engine includes a fan section, a heat exchanger, and inlet door. The fan section is configured to generate an airflow. The heat exchanger is configured to transfer heat from a thermal management system to the airflow. The inlet door is configured to modulate the airflow to the heat exchanger.