Gas Turbine Rotor Heat Shield for Thermal Gradient Control
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Solution Overview
Problem
Gas turbine engine rotor disks experience thermal gradients due to coolant delivery, which can reduce their lifespan and efficiency, as existing cooling methods often exacerbate these gradients.
Innovation Solution
A heat shield is introduced to separate the coolant passage into two sections, with axial retention features and longitudinal protrusions to maintain its position relative to the rotor disk, reducing thermal conduction and minimizing vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If coolant is delivered to rotor blades through radial opening in root, then cooling effect on rotor blade is achieved, but thermal gradients on rotor disk are exacerbated
Solution Approach 1:
The cavity is segmented into a first passage and a second passage by the heat shield. The first passage allows coolant flow to the blade while the second passage provides a thermal barrier, separating the cooling function from the thermal protection function.
Solution Approach 2:
The heat shield acts as an intermediary component between the coolant passage and the rotor disk. It mediates the thermal interaction by providing thermal insulation to the rotor disk while still allowing the coolant to reach the blade through the first passage.
2Reliability
If heat shield is inserted into slot in rotor disk, then thermal insulation is provided, but assembly complexity increases
Solution Approach 1:
The heat shield is combined with the root assembly as an integrated unit. The root is inserted into the slot in the rotor disk, and the heat shield is positioned within the root, merging multiple functions (coolant delivery, thermal insulation, and structural support) into a single integrated component.
3Speed
If cooling air flow rate is reduced by ensuring air leaves at radius less than entry, then pressure head results to slow flow, but cooling effectiveness may be reduced
Solution Approach 1:
The cooling air flow is segmented into different paths: the first passage directs coolant to the blade cooling passages, while the second passage allows for flow management at the root level. This segmentation enables independent optimization of blade cooling and root thermal protection.
Solution Approach 2:
Different regions of the cooling system have different flow characteristics optimized for their specific functions. The first passage maintains higher flow velocity for effective blade cooling, while the second passage manages flow rate for thermal insulation of the rotor disk.
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 heat shield effectively insulates the rotor disk from thermal gradients caused by coolant, enhancing the rotor's lifespan and operational stability by reducing thermal conduction and vibrations.
Implementation Method 1
The heat shield separates the cavity into a first passage adjacent to the root and a second passage on a side of the heat shield opposite the root
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A gas turbine engine rotor assembly includes a rotor disk (68) with a slot (104). A rotor blade (64) has a root (74) supported within the slot (104). A heat shield (106) is arranged in a cavity in the slot (104) between the root (74) and the rotor disk (68). An axial retention feature (116,118) is configured to axially maintain the heat shield (106) within the slot (104).