Gas Turbine Compressor Hub Cooling via Bleed Air Heat Exchange
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Solution Overview
Problem
High-pressure compressor stages in advanced gas turbine engines face thermal and mechanical stresses due to increased temperatures and pressures, exceeding the capabilities of existing materials, particularly at the last stage of the high-pressure compressor where the rear rim and hub require effective cooling to prevent damage.
Innovation Solution
A passive cooling system integrated with bleed air pipes and heat exchangers that direct cool air from an early compressor stage to the rear rim and hub, using a combination of bleed pipes and heat exchangers to absorb heat and reduce thermal stress, while maintaining system performance and optimizing thermodynamic cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the pressure and rotational speed of the gas turbine engine are increased to exceed prior thresholds, then the power and efficiency of the engine are improved, but the thermal and mechanical stresses on the high pressure compressor components exceed material limitations
Solution Approach 1:
Cool air is introduced as an intermediary substance between the hot high-pressure gas and the rear rim/hub components. This cool air flows through passages in the rotor assembly, absorbing heat from the rear rim and hub, thereby protecting these components from thermal damage while enabling higher operating pressures and temperatures that increase engine power
Solution Approach 2:
The invention uses pneumatic cooling by directing compressed cool air through passages formed in the rotor assembly (including the rear rim and hub). The pressurized cooling air flows radially outward through these passages, efficiently removing heat from the high-stress components without requiring mechanical moving parts or external cooling systems
2Temperature
If cooling systems are added to the high pressure compressor, then the temperature of the rear rim and hub is reduced, but the device complexity increases
Solution Approach 1:
The cooling passages are merged with the existing rotor assembly structure. The passages are formed directly within the rear rim and hub components themselves, combining the structural and cooling functions into a single integrated assembly. This eliminates the need for separate external cooling systems, pipes, and actuators that would increase device complexity
Solution Approach 2:
The rotor assembly serves its own cooling needs through internally formed passages that distribute cooling air throughout the structure. The system is self-contained, requiring no external cooling equipment or complex control systems, thereby reducing overall device complexity while effectively managing temperatures
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 cooling system effectively reduces the temperature of the rear rim and hub by up to 100°F (55°C), extending the life of the gas turbine engine and managing thermal stresses without negative performance impact, while allowing for smaller heat exchanger sizes due to efficient heat transfer.
Implementation Method 1
A passive cooling system integrated with bleed air pipes and heat exchangers that direct cool air from an early compressor stage to the rear rim and hub, using a combination of bleed pipes and heat exchangers to absorb heat and reduce thermal stress
Data Source
Figure 1
Figure 2
Figure 3a~3b
AI summary
A gas turbine engine (10) includes a turbine (24) and a high pressure compressor (18). The high pressure compressor (18) includes a last stage having a last stage compressor blade (34a) and a last stage vane (36a). The gas turbine engine (10) includes a first flow path through which bleed air flows to the turbine (24) and a second flow path through which air from the last stage of the high pressure compressor (18) flows. The bleed air in the first flow path exchanges heat with a portion of the air in the second flow path in a heat exchanger (50) to cool the air in the second flow path. The cooled air in the second flow path is returned to the high pressure compressor (18) to cool the high pressure compressor (18).