Buffer Air Augmentation Using ATS Exhaust for Start-Up Pressurization
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Solution Overview
Problem
Existing gas turbine engines face challenges in providing adequate pressurization to engine compartments during start-up, leading to potential contamination of cabin ventilation air with engine oil, especially when compressor rotor speeds are below idle.
Innovation Solution
A buffer air augmentation system that utilizes ATS exhaust gas to pressurize engine compartments through flow ducting and control devices, ensuring adequate pressure differential to prevent oil leakage and contamination, controlled by a controller and sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If compressor bleed air is used to pressurize engine compartments during start-up, then engine compartment pressurization is achieved, but compressor rotor speeds must be above idle which limits start-up capability
Solution Approach 1:
The patent introduces ATS exhaust gas as an intermediary substance to provide buffer air pressurization during start-up. The exhaust gas from the air turbine starter is redirected through flow ducting to the engine compartment, serving as a mediator that enables pressurization without requiring the compressor to be operational at sufficient speeds.
Solution Approach 2:
The air turbine starter's exhaust gas, which would otherwise be wasted, is utilized to provide the necessary buffer air pressurization. The system uses its own operational byproduct (exhaust gas) to solve the pressurization problem during start-up, eliminating the need for external pressurization sources.
2Quantity of substance
If adequate compressor bleed air flow is provided to pressurize compartments and ventilate cabin, then both functions are achieved, but it is challenging during start-up when compressor rotor speeds are below idle
Solution Approach 1:
ATS exhaust gas serves as an intermediary that supplements or replaces compressor bleed air during start-up. The flow ducting system redirects this exhaust gas to the engine compartment, providing the necessary quantity of pressurization air without relying on compressor output.
Solution Approach 2:
The system changes the source parameter from compressor bleed air to ATS exhaust gas during the start-up phase. This parameter substitution allows adequate pressurization flow to be achieved when compressor rotor speeds are below idle, making start-up operation feasible.
3Reliability
If buffer air pressurization is not adequate, then engine compartment pressurization is maintained, but air contaminated with engine oil mixes with compressor bleed air for cabin ventilation
Solution Approach 1:
ATS exhaust gas is introduced as an intermediary pressurization source that prevents the need to rely on potentially contaminated compressor bleed air during start-up. By providing adequate pressurization through this alternative source, the system prevents oil-contaminated air from mixing with cabin ventilation air.
Solution Approach 2:
The system takes preliminary action by establishing adequate buffer air pressurization through ATS exhaust gas before compressor bleed air becomes sufficient. This preemptive pressurization prevents oil contamination from occurring in the first place during the vulnerable start-up phase.
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
Effectively maintains engine compartment pressure during start-up, preventing oil contamination and ensuring smooth engine operation by controlling ATS exhaust gas flow, thus enhancing engine performance and safety.
Implementation Method 1
The ATS is configured to receive a flow of compressed air from a compressed air source
Implementation Method 2
The system is configured to provide the flow of ATS exhaust gas to the engine compartment during a start-up segment of an engine operational cycle
Data Source
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AI summary
A gas turbine engine (20) is provided that includes compressor and turbine sections (30), an engine compartment, an air turbine starter (ATS) (46), and a buffer air augmentation system (44). The compressor and turbine sections (30) are engaged by a shaft (40). The ATS (46) is disposed to drive the compressor and turbine sections (30). The air turbine starter (46) is configured to receive a flow of compressed air from a compressed air source. The air turbine starter (46) has an exhaust port (46B) configured to pass a flow of ATS exhaust gas flow. The buffer air augmentation system (44) includes flow ducting (52) configured to selectively provide fluid communication of the flow of ATS exhaust gas between the exhaust port of the air turbine starter (46) and the engine compartment. The system (44) is configured to provide the flow of ATS exhaust gas to the engine compartment during a start-up segment of an engine operational cycle.