Boost Compressor Air Routing for Low-Flow Engine Heat Rejection
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Solution Overview
Problem
The integration of hybrid electric systems in gas turbine engines generates excess waste heat, particularly during low-airflow conditions like taxiing and idling, which existing heat exchanger solutions cannot effectively manage without increasing weight and drag.
Innovation Solution
A system that redirects compressed air from a boost compressor to existing heat exchangers during low-airflow conditions, using switching valves to augment heat rejection capacity without enlarging the heat exchanger or adding weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the size of heat exchangers is increased to reject excess heat in low air-flow conditions, then heat management capacity is improved, but weight and drag increase
Solution Approach 1:
The patent employs a boost compressor that can be activated on-demand during low air-flow conditions (taxiing, landing, idling) to compress ambient air and force it through the heat exchangers. This dynamic activation only when needed allows the system to maintain compact heat exchanger size while achieving adequate heat rejection capacity during critical low-speed operations.
Solution Approach 2:
The system changes the pressure parameter of the air flowing through the heat exchangers by using the boost compressor to increase air pressure during low air-flow conditions. This parameter change allows existing heat exchangers to operate effectively at higher pressures, improving heat transfer efficiency without requiring larger surface areas, thereby avoiding increased weight.
2Temperature
If the size of heat exchangers is increased to reject excess heat in low air-flow conditions, then heat management capacity is improved, but drag increases
Solution Approach 1:
The boost compressor is dynamically activated only during low air-flow conditions when external cooling is insufficient. During cruise and high-speed operations, the system relies on natural ram air cooling without the boost compressor, maintaining a streamlined configuration that minimizes drag. The nautical duct design also optimizes airflow paths to reduce drag penalties.
Solution Approach 2:
The patent introduces a fourth dimension (time/operational mode) to the heat rejection solution. Instead of permanently enlarging heat exchangers, the system uses temporal activation of the boost compressor only when needed (low air-flow conditions). This dimensional approach allows the heat exchangers to remain compact while achieving adequate cooling capacity during critical periods without permanently increasing drag.
3Temperature
If a boost compressor is added to augment heat rejection, then thermal management efficiency is improved, but device complexity increases
Solution Approach 1:
The boost compressor is designed with multi-functionality, serving both the TCLA (Turbine Cooling and Leakage Air) system and the thermal management system. The switching valve network enables a single boost compressor to fulfill multiple cooling functions across different operational modes, reducing overall system complexity compared to having separate dedicated compressors for each function.
Solution Approach 2:
A switching valve network acts as an intermediary between the boost compressor and multiple downstream components (heat exchangers, TCLA system, turbine). This intermediary control system efficiently routes compressed air to where it is needed, managing the complexity of coordinating multiple functions through a centralized, intelligent valve control architecture rather than requiring complex mechanical linkages or multiple independent systems.
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
Effectively manages excess waste heat during low-airflow conditions without increasing weight or drag, enhancing thermal management efficiency.
Implementation Method 1
a first heat exchanger disposed in a second portion of the nacelle, where a fan stream passes through the second portion of the nacelle
Implementation Method 2
The second switching valve is configured to direct gas to the boost compressor
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
A system comprises a fan (107) disposed at an intake of a nacelle (101), and a gas turbine (105). The gas turbine (105) includes compressor (109), combustor (111), and turbine (113) sections. A first heat exchanger (117) is disposed in the nacelle (101) in a fan stream. A first switching valve (125) receives gas from the fan stream and directs the received gas to a second switching valve (127) or the turbine section (113). The second switching valve (127) directs gas to a boost compressor (119) and receives gas from the first switching valve (125) or a high pressure bleed from the compressor section (109). A third switching valve (129) receives gas from the boost compressor (119) and directs compressed gas to the first heat exchanger (117) or the turbine section (113).