Downstream Pressure Injection for Turbine Shaft Break Overspeed
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Gas turbine engines face the risk of turbine disintegration due to rapid acceleration during a shaft break event, leading to potential engine damage, as existing overspeed protection methods may not act quickly enough to mitigate the issue.
Innovation Solution
A pressure equalization apparatus introduces pressurized fluid directly downstream of the turbine to increase local pressure, reducing the pressure differential and preventing overspeed by regulating fluid flow using a control system and mechanisms like valves, pumps, or fuses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing overspeed protection methods are used to protect against turbine overspeed, then turbine speed can be limited, but the response time is insufficient to prevent turbine disintegration
Solution Approach 1:
The system pre-pressurizes the fluid supply system before a shaft break event occurs, so that when the event happens, the pressurized fluid can be immediately introduced downstream of the turbine without delay for pressurization. This preliminary preparation of the fluid system enables instantaneous response to limit turbine speed.
Solution Approach 2:
A pressurized fluid (such as air or inert gas) is introduced as an intermediary substance downstream of the turbine to rapidly increase local pressure and reduce the pressure differential across the turbine. This intermediary fluid acts as a mechanical brake to limit turbine acceleration without requiring direct mechanical contact or complex control systems.
2Reliability
If pressurized fluid is introduced downstream of the turbine to reduce pressure differential, then turbine speed is limited, but complex control systems are required
Solution Approach 1:
The system uses the existing pressurized fluid infrastructure of the gas turbine engine (such as compressor bleed air or inert gas systems) to provide overspeed protection, eliminating the need for separate complex control systems. The available pressurized fluid in the engine naturally serves the dual purpose of normal operation and overspeed protection.
Solution Approach 2:
The invention employs pneumatic principles by introducing pressurized gas or air downstream of the turbine to create a backpressure that limits turbine speed. This pneumatic approach simplifies the control mechanism compared to mechanical or electronic systems, as it uses the inherent compressibility and pressure characteristics of gases to automatically regulate turbine acceleration.
3Speed
If rapid response is achieved by introducing pressurized fluid immediately, then turbine speed is limited in time, but precise control of fluid flow is challenging
Solution Approach 1:
The system introduces a substantial amount of pressurized fluid downstream of the turbine to ensure rapid and effective speed limitation, even if the exact quantity is not precisely controlled. The excessive or partial introduction of pressurized fluid guarantees that the pressure differential is sufficiently reduced to prevent turbine disintegration, prioritizing safety over precise flow control.
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 the likelihood of turbine disc burst and extensive engine damage by quickly stabilizing turbine speed during a shaft break event, enhancing safety in high-velocity vehicles like aircraft.
Implementation Method 1
introduce a pressurised fluid into a core airflow at a region directly downstream of the turbine in the event of a shaft break to directly increase a local pressure at the downstream region of the turbine and thereby reduce the pressure differential across the turbine
Data Source
AI summary
An apparatus and method for reducing a pressure differential across a turbine 19 of a gas turbine engine 10 during a shaft break event, comprises a pressure equalization apparatus 200, 300, 400, 500, 600, 700 configured to introduce a pressurised fluid into a core airflow A at a region directly downstream of the turbine 19 in the event of a shaft break to directly increase a local pressure at the downstream region 29 of the turbine 19 and thereby reduce the pressure differential across the turbine 19. The reduction in the pressure differential may result in a reduction in the acceleration of the turbine 19.