Gas Turbine Rotor Phase Change Material Cooling
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Solution Overview
Problem
The significant temperature differential between the inner and outer portions of a gas turbine engine rotor leads to thermal stress, limiting the compression ratios and posing a risk of structural failure, particularly in the compressor section.
Innovation Solution
A rotor design incorporating a cooling cavity with phase change material that transitions between liquid and gas states within the cavity, facilitating heat transfer from the outer to the inner rotor portion, thereby reducing thermal stress and maintaining an isothermal condition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If higher compression ratios are pursued to improve cycle thermal efficiency and fuel burn, then thermal stress in the rotor increases, leading to potential structural failure
Solution Approach 1:
The patent employs phase change material (PCM) that transitions between solid and liquid states to absorb and release thermal energy. The PCM is contained in thermal energy storage elements positioned within the rotor structure, allowing it to undergo phase transitions that mitigate thermal stress and maintain rotor integrity during high-compression-ratio operation.
Solution Approach 2:
The patent replaces traditional mechanical cooling systems with a passive thermal energy storage system using phase change material. Instead of using active cooling mechanisms, the system utilizes the latent heat of phase transitions to automatically regulate temperature and reduce thermal stress in the rotor.
2Temperature
If traditional cooling methods are used to reduce thermal stress, then the system complexity increases, but the temperature differential control remains insufficient
Solution Approach 1:
The phase change material system is self-regulating and requires no external control mechanisms. The PCM automatically absorbs heat when transitioning from solid to liquid state and releases heat when transitioning from liquid to solid state, providing passive thermal management that reduces rotor temperature differential without adding system complexity.
Solution Approach 2:
The rotor is divided into multiple thermal zones with discrete thermal energy storage elements containing phase change material. These segmented cooling elements are strategically positioned within the rotor structure to address specific high-stress areas, allowing targeted thermal management without requiring a complex overall cooling system.
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 solution effectively reduces thermal stress, mitigates failure modes like low-cycle fatigue and thermal mechanical fatigue, enabling higher compression ratios, increased efficiency, and improved fuel burn by maintaining a consistent rotor temperature.
Implementation Method 1
A phase change material is arranged in the cavity. The phase change material is configured to be arranged in the first chamber in a first state and in the second chamber in the second state. The passageway is configured to carry the phase change material between the second and first chambers once changed between the first and second states.
Implementation Method 2
The phase change material is configured to transition from a liquid to a gas in the first chamber during engine operation. The phase change material is configured to transition from a gas to a liquid in the second chamber during engine operation.
Implementation Method 3
facilitating heat transfer from the outer to the inner rotor portion, thereby reducing thermal stress and maintaining an isothermal condition
Data Source
AI summary
A gas turbine engine rotor includes a rotor that provides a cooling cavity. The cooling cavity has a first chamber and a second chamber that are fluidly connected to one another by a passageway. At least one of the first and second rotor portions is configured to support a blade that is fluidly isolated from the cavity. A phase change material is arranged in the cavity. The phase change material is configured to be arranged in the first chamber in a first state and in the second chamber in the second state. The passageway is configured to carry the phase change material between the second and first chambers once changed between the first and second states.