Annular-Duct Heat Exchanger for Gas Turbine Noise Control
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Solution Overview
Problem
Existing gas turbine engines face challenges in effectively dissipating heat generated by various systems during operation, leading to inefficiencies and the need for iterative redesigns to balance heat transfer, pressure drop, and noise attenuation across different flight conditions.
Innovation Solution
A heat exchanger design is implemented within an annular duct of the gas turbine engine, optimized to meet initial design requirements for heat transfer, pressure drop, and noise attenuation, using various types such as fin-based, plate fin, shell and tube, counter-flow, and onion style heat exchangers, with adjustments for different flight conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heat exchanger is added to dissipate heat from various systems, then heat dissipation capability is improved, but device complexity and pressure drop increase
Solution Approach 1:
The patent combines multiple heat exchangers into a single integrated heat exchanger assembly located in the annular duct. This merged structure consolidates heat dissipation functions for multiple systems (thrust generating systems, lubrication systems, electric motors/generators, hydraulic systems) into one unified component, reducing overall device complexity while maintaining comprehensive heat dissipation capability.
Solution Approach 2:
The integrated heat exchanger assembly serves multiple functions simultaneously: it dissipates heat from various engine systems, manages thermal loads across different operating conditions, and is positioned to utilize the annular duct space efficiently. This multi-functional design eliminates the need for separate heat exchangers for each system, thereby reducing device complexity.
2Temperature
If heat exchanger size is increased to improve heat transfer, then heat transfer efficiency is improved, but pressure drop increases
Solution Approach 1:
The patent positions the integrated heat exchanger assembly in the annular duct where it can utilize local flow characteristics and temperature gradients. The heat exchanger is strategically located to intercept hot气流 from various systems at specific locations, allowing efficient heat transfer without requiring the entire duct cross-section to be occupied by heat exchange surfaces, thus minimizing pressure drop.
Solution Approach 2:
The heat exchanger assembly is designed to handle the critical heat dissipation requirements for various systems without necessarily treating the entire airflow. It focuses on extracting heat from specific portions of the airflow where thermal loads are highest, achieving sufficient heat transfer efficiency without the excessive heat exchange surface area that would cause unacceptable pressure drop.
3Temperature
If heat exchanger is optimized for initial design requirements, then heat transfer and noise attenuation are improved, but adaptability to varying flight conditions deteriorates
Solution Approach 1:
The patent employs variable geometry features in the heat exchanger assembly, including adjustable flow distribution elements and modifiable heat exchange surface configurations. These dynamic components allow the heat exchanger to adapt its characteristics (such as flow distribution and heat transfer area) to match varying thermal loads and flight conditions, maintaining optimal heat transfer performance across different operating regimes.
Solution Approach 2:
The heat exchanger assembly incorporates the ability to change operational parameters such as flow rate distribution, heat exchange surface area utilization, and thermal conductivity characteristics. By adjusting these parameters in response to varying flight conditions (altitude, speed, thermal loads), the system maintains effective heat transfer performance without being locked into a single optimized configuration for one specific operating condition.
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 optimized heat exchanger achieves efficient heat dissipation, reduces noise levels, and maintains acceptable pressure drop across varying flight conditions, eliminating the need for iterative redesigns and improving overall engine performance.
Implementation Method 1
a heat exchanger positioned within the flow path and extending along the circumferential direction
Implementation Method 2
optimized to meet initial design requirements for heat transfer, pressure drop, and noise attenuation
Data Source
AI summary
A heat exchanger positioned within an annular duct of a gas turbine engine is provided. The heat exchanger extends substantially continuously along the circumferential direction and defining a heat exchanger height equal to at least 10% of a duct height. An effective transmission loss (ETL) for the heat exchanger positioned within the annular duct is between 5 decibels and 1 decibels for an operating condition of the gas turbine engine. The heat exchanger includes a heat transfer section defining an acoustic length (Li), and wherein an Operational Acoustic Reduction Ratio (OARR) is greater than or equal to 0.75 to achieve the ETL at the operating condition.