Diffuser Case Heat Exchanger for Bleed Air Cooling
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Solution Overview
Problem
Gas turbine engines face challenges in enhancing thermal and propulsive efficiencies, with existing cooling methods not fully addressing the heat management needs of the turbine section, particularly in maintaining component operating temperatures within defined ranges.
Innovation Solution
The integration of a heat exchanger within the diffuser case, which includes separate passages for bypass flow and bleed airflow, allows for efficient cooling of bleed air before directing it to the turbine section, using a mixing chamber and onboard injectors to distribute cooled air effectively, and control valves to manage airflow, forming an integral part of the diffuser case to minimize profile intrusion and optimize cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heat exchanger is integrated within the diffuser case, then cooling efficiency of bleed air is improved, but device complexity increases
Solution Approach 1:
The heat exchanger is integrated within the diffuser case structure, combining two separate components (heat exchanger and diffuser case) into a single unified structure. This merging approach improves cooling efficiency by providing dedicated cooling passages while minimizing the increase in overall device complexity through shared structural elements.
Solution Approach 2:
The heat exchanger passages are nested within the diffuser case structure, with cooling passages defined inside the diffuser case walls. This nesting arrangement allows the heat exchanger functionality to be embedded within the existing diffuser case geometry, improving thermal management without significantly increasing external dimensions or overall system complexity.
2Temperature
If separate passages are provided for bypass flow and bleed airflow, then thermal management efficiency is improved, but device complexity increases
Solution Approach 1:
The diffuser case is segmented into separate passages for bypass flow and bleed airflow, with distinct inlet and outlet regions for each flow path. This segmentation allows independent control and optimization of thermal management for different airflow paths, maintaining component temperatures within operational ranges while using clearly defined separate channels rather than mixed flows.
Solution Approach 2:
Different regions of the diffuser case are assigned different functions with appropriate local properties - the bypass flow passages are configured for one thermal path while bleed air passages are configured for another. This local differentiation optimizes thermal management efficiency by providing specialized flow paths tailored to specific cooling requirements without requiring complete system redesign.
3Ease of manufacture
If heat exchanger is formed as integral part of diffuser case, then manufacturing complexity is reduced, but design flexibility decreases
Solution Approach 1:
The heat exchanger is formed as an integral part of the diffuser case, combining what would traditionally be separate manufactured components into a single monolithic structure. This merging simplifies manufacturing by eliminating assembly steps between heat exchanger and diffuser case, reducing potential leakage paths, and decreasing the number of parts, while the internal passage geometry can still be optimized for thermal performance.
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
This configuration enhances cooling efficiency, maintains component temperatures within operational ranges, and improves engine performance by effectively utilizing bleed air and bypass airflow for thermal management, thereby enhancing thermal and propulsive efficiencies.
Implementation Method 1
The heat exchanger portion comprises a bypass flow path for receiving a flow of bypass air and a bleed air flow path for receiving a flow of bleed air communicated from a diffuser surrounding a combustor of the engine. The heat exchanger cools the bleed air by placing the bleed airflow in thermal communication with the bypass airflow.
Implementation Method 2
The heat exchanger cools the bleed air by placing the bleed airflow in thermal communication with the bypass airflow
Implementation Method 3
The heat exchanger cools the bleed air by placing the bleed airflow in thermal communication with the bypass airflow
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A gas turbine engine (20) includes a bypass duct (16) for a bypass airflow and a diffuser case (66) including an inlet (92) in communication with the bypass duct (16) for communicating a bypass flow (76) to a heat exchanger portion (68). An outlet passage (94) extends through the bypass duct (16) to exhaust airflow exiting the heat exchanger portion (68) outside of the bypass duct (16).