Constant-Speed Impeller Pump for Gas Turbine Thermal Management
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Solution Overview
Problem
Gas turbine engines face challenges with large and heavy heat exchangers in thermal management systems and performance losses due to bleed ports used for environmental control systems, leading to inefficiencies and increased packaging volume and complexity.
Innovation Solution
A constant-speed impeller pump system driven by an integrated drive pump, connected to a towershaft, which raises air pressure for both thermal management and environmental control systems, reducing the need for large heat exchangers and minimizing bleed air losses by using a single impeller and integrated drive pump to provide constant-speed power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bleed ports are used to provide ECS air from the high pressure compressor, then environmental control is achieved, but engine performance is reduced due to loss of compressed air
Solution Approach 1:
The patent extracts the ECS air supply function from the bleed port system and relocates it to the impeller pump system. The impeller pump draws air from the bypass duct and delivers it to the ECS, eliminating the need to extract air from the high pressure compressor and thereby preventing engine performance loss while maintaining environmental control capability
Solution Approach 2:
The patent introduces an intermediary system (impeller pump with bypass duct intake) between the engine airflow and the ECS. This intermediary provides ECS air from a different source (bypass duct) rather than directly from the compressor bleed ports, resolving the conflict between ECS operation and engine performance
2Temperature
If heat exchangers are used to reject internal heat in the TMS, then thermal management is achieved, but the heat exchangers become prohibitively large and heavy as fan pressure ratio drops
Solution Approach 1:
The patent merges the TMS heat rejection function with the ECS air delivery system. The impeller pump serves dual purposes: delivering ECS air and providing pressurized flow through which heat exchangers can operate more efficiently. This integration allows compact heat exchanger design by utilizing the pressurized airflow path already established for ECS purposes
Solution Approach 2:
The impeller pump system is designed to perform multiple functions simultaneously: providing ECS air supply, enabling TMS heat rejection, and delivering pressurized air to the aircraft. This multi-functionality reduces the need for separate dedicated systems, thereby reducing overall weight and volume while maintaining thermal management capability
3Adaptability or versatility
If a variable speed pump is used in the engine accessory system, then the pump can adapt to varying engine conditions, but the pump speed fluctuates causing inefficiency and increased complexity in maintaining constant speed
Solution Approach 1:
The patent introduces an integrated drive pump as an intermediary device between the variable speed engine accessory system and the constant speed impeller pump. The integrated drive pump absorbs speed variations from the engine and delivers constant speed rotation to the impeller pump, enabling the impeller to operate at optimal constant speed while still adapting to engine conditions through the drive pump's speed variation absorption
Solution Approach 2:
The patent changes the speed parameter of the impeller pump from variable (directly coupled to engine) to constant (via integrated drive pump). This parameter change optimizes impeller performance by maintaining constant rotational speed, while the integrated drive pump handles the speed adaptation to engine conditions, effectively decoupling the impeller speed from engine speed variations
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 reduces the size and weight of thermal management system components, decreases environmental control system plumbing, and enhances efficiency by eliminating bleed air losses, resulting in reduced packaging space, improved reliability, and lower maintenance costs.
Implementation Method 1
the impeller pump being configured to raise the pressure of air received from the bypass duct
Data Source
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Figure 5
AI summary
A gas turbine engine has a spool, a towershaft connected to the spool, an impeller pump, and a speed control pump connected to the towershaft and to the impeller pump for driving the impeller pump at a constant speed.