HPC Thermal Management via Cooled Cooling Air and Bore Flow
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Solution Overview
Problem
High-pressure compressor (HPC) metal temperatures in gas turbine engines exceed material limits due to increasing overall pressure ratio (OPR), necessitating effective thermal management to prevent material degradation and enable higher OPR cycles.
Innovation Solution
A thermal management system that includes cantilever vanes, rerouted bore flow, and cooled cooling air (CCA) to manage metal temperatures at the aft end of the HPC, utilizing CCA to flow outward into the gas path and through the HPC drive cone and C-T shaft, and re-routing bore flow to enhance heat transfer and reduce thermal gradients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the overall pressure ratio (OPR) is increased to improve engine efficiency, then the engine efficiency and specific fuel consumption are improved, but the HPC metal temperatures exceed material limits causing material degradation
Solution Approach 1:
The patent extracts hot compressor air from the compressor exit and routes it through the HPC cone shaft and C-T shaft to cool critical metal components. This separation of hot flow from critical thermal zones removes excess heat from temperature-sensitive areas, enabling higher OPR operation without exceeding material temperature limits.
Solution Approach 2:
The patent introduces a secondary flow system that acts as an intermediary thermal management pathway. Cooled cooling air (CCA) is introduced as an intermediary substance to absorb heat from HPC components, serving as a heat transfer medium between the hot compressor exit air and the critical metal surfaces that need thermal protection.
2Temperature
If a secondary flow system is implemented to cool HPC components, then metal temperatures are managed within material limits, but the system complexity and manufacturing cost increase
Solution Approach 1:
The secondary flow system serves multiple functions: it cools the HPC cone shaft, cools the C-T shaft, and manages thermal gradients across critical components. By using a single integrated flow pathway that accomplishes multiple cooling objectives, the patent reduces the need for separate cooling systems for each component, thereby limiting the increase in overall system complexity.
3Stability of the object's composition
If cooled cooling air (CCA) is introduced to manage thermal gradients, then metal temperature uniformity is improved, but the system complexity and assembly difficulty increase
Solution Approach 1:
The patent incorporates cooling air pathways and thermal management features into the component design before final assembly. The bore flow circuits and CCA introduction points are pre-configured in the HPC and shaft assemblies, allowing thermal management to be built-in during manufacturing rather than added as separate post-assembly components, thereby reducing assembly difficulty.
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 system effectively manages metal temperatures, enabling higher OPR cycles, reducing core size, improving efficiency, and minimizing fuel burn by maintaining temperatures within material limits and reducing thermal stress.
Implementation Method 1
a secondary flow system that plumbs hot compressor air down the HPC cone shaft and along the C-T shaft
Implementation Method 2
CCA systems typically focus on managing temperatures within the hot section of the engine
Implementation Method 3
re-routing bore flow to enhance heat transfer and reduce thermal gradients
Data Source
Figure 1~2
Figure 3~4
AI summary
A gas turbine engine includes an inner shaft extending axially along the gas turbine engine, a plurality of disks extending radially inwardly and toward the inner shaft, at least one hole in at least one of the plurality of disks, and an obstruction positioned between the inner shaft and an end of the disk having the at least one hole, such that a bore flow that flows along an axial length of the inner shaft is obstructed from flowing along the shaft by the obstruction, and forced to flow radially outward from the obstruction, through the at least one hole, and radially inward toward the inner shaft.