Buffer Air Pump in Accessory Gearbox for Gas Turbine Cooling
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Solution Overview
Problem
Gas turbine engines require cooling air that is both cooler and higher in pressure than the components they need to cool, but existing systems often necessitate the use of heat exchangers to achieve the desired temperature and pressure, which can be complex and weight-intensive.
Innovation Solution
A buffer air pump is integrated within an accessory gearbox, using an impeller supported by a tower shaft to pressurize bypass air, eliminating the need for external heat exchangers by providing cooling air at a desired temperature and pressure through conduits and passages directly to components like bearing assemblies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If heat exchangers are used to cool the air to the desired temperature, then the cooling air temperature is improved, but the device complexity and weight increase
Solution Approach 1:
The invention extracts and eliminates the heat exchanger component from the cooling system. Instead of using a heat exchanger to cool the air, the system directly uses the cool bypass air from the compressor, simplifying the overall system architecture while maintaining effective cooling performance.
Solution Approach 2:
The bypass air from the compressor serves its own cooling function directly without requiring additional cooling equipment. The cool air that is diverted from the main combustion path is self-sufficient for cooling engine components, eliminating the need for external heat exchangers.
2Temperature
If heat exchangers are used to cool the air to the desired temperature, then the cooling air temperature is improved, but the weight increases
Solution Approach 1:
The heat exchanger is extracted and removed from the system. The cooling function is achieved by directly utilizing the cool bypass air, eliminating the weight of the heat exchanger component while maintaining the temperature requirements for effective cooling.
3Stress or pressure
If a pump is used to pressurize the bypass air, then the cooling air pressure is improved, but the device complexity increases
Solution Approach 1:
The bypass air system serves multiple functions: it provides cooling air for engine components and simultaneously provides pressurized air for other engine systems. This multi-functionality eliminates the need for a dedicated pump, reducing system complexity while maintaining the required pressure levels.
Solution Approach 2:
The invention merges the cooling air supply function with the existing bypass air system. The bypass air that would otherwise be unused is integrated into the cooling system, combining multiple functions into a single streamlined architecture that reduces overall system complexity.
4Ease of operation
If external ductwork is used to deliver cooling air, then the cooling air delivery is improved, but the device complexity and weight increase
Solution Approach 1:
The cooling air passages are nested within the existing engine structure and component housings. Instead of adding external ductwork, the cooling channels are integrated into the bearing housings and other engine components, delivering cooling air efficiently while minimizing additional structural complexity.
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 solution provides efficient cooling to gas turbine engine components without the need for extensive external ductwork or heat exchangers, simplifying assembly and reducing weight while ensuring the cooling air is at a suitable temperature and pressure for effective cooling.
Implementation Method 1
An impeller supported within a scroll housing pressurizes the incoming bypass air and directs the pressurized air through passages to a component requiring cooling
Implementation Method 2
The buffer air pump draws in relatively cool air from the bypass flow, pressurizes the air with the impeller and sends the air through conduits and passages within the gas turbine engine to the component that requires cooling such as for example, a bearing assembly
Data Source
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AI summary
A buffer air pump (35) provides pressurized cooling air for cooling components of a gas turbine engine. The buffer air pump (35) is supported on and/or within an accessory gearbox (30) and draws bypass air in through an inlet manifold (32). An impeller (52) supported within a scroll housing (34) pressurizes the incoming bypass air and directs the pressurized air through passages to a component requiring cooling. The buffer air pump (35) draws in relatively cool air from the bypass flow, pressurizes the air with the impeller (52) and sends the air through conduits and passages (56) within the gas turbine engine to the component that requires cooling such as a bearing assembly.