Nested Oil Pipe Assembly for Gas Turbine Leak Detection
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Solution Overview
Problem
Gas turbine engine oil systems face challenges in detecting and containing leaks in oil pipes, which can disrupt lubrication, pose fire hazards, and require costly and disruptive repairs, especially in aircraft where safety and operational efficiency are critical.
Innovation Solution
An oil pipe assembly with a first pipe surrounded by a second pipe, a restrictor, and sensors to detect changes in air pressure and temperature, allowing for early leak detection and containment, ensuring oil supply continuity and preventing fires by redirecting leaks to safe zones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single pipe is used to supply oil in the gas turbine engine, then the device complexity is reduced, but the reliability deteriorates because a single leak can disrupt oil supply and pose fire hazards
Solution Approach 1:
The patent implements a nested pipe structure where a first pipe (oil supply) is positioned inside a second pipe (cooling air supply). This nested configuration allows the system to maintain compact dimensions while providing redundant protection - if the inner oil pipe leaks, the outer cooling air pipe contains the leak and prevents fire hazards, thereby improving reliability without significantly increasing overall device complexity
Solution Approach 2:
The patent divides the single pipe function into separate segmented pipes - an inner first pipe for oil supply and an outer second pipe for cooling air supply. This segmentation allows independent monitoring and containment of different fluid streams, so that a leak in one pipe does not necessarily compromise the entire system, thus improving reliability while maintaining manageable complexity
2Reliability
If sensors and a restrictor are added to detect and contain leaks, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The patent introduces a restrictor as an intermediary component in the second pipe that limits the flow of cooling air. This restrictor serves as a mediator that, when combined with pressure and temperature sensors, enables leak detection without requiring complex monitoring systems. The restrictor creates a controllable flow condition that makes leak detection more straightforward, improving reliability while adding only moderate complexity
Solution Approach 2:
The patent implements a feedback mechanism where pressure sensors and temperature sensors continuously monitor conditions in the second pipe and provide data to a controller. When leak indicators are detected (pressure drop or temperature change), the controller activates an alarm or shuts down the system. This feedback loop improves reliability by enabling real-time leak detection while maintaining manageable complexity through automated monitoring rather than complex mechanical containment systems
3Reliability
If a doubled-skinned pipe is used to contain leaks, then the reliability is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent employs flexible sealing elements and thin film barriers between the inner first pipe and outer second pipe. These flexible sealing components can accommodate minor manufacturing tolerances and thermal expansion differences, maintaining effective leak containment without requiring extremely tight manufacturing precision. The flexibility of the sealing elements compensates for small dimensional variations, thus improving reliability while reducing the stringency of manufacturing precision requirements
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 detects leaks in inaccessible engine parts, minimizes oil supply disruptions, prevents fires, and allows for safe operation without diverting aircraft for urgent repairs, enhancing safety and reducing operational costs.
Implementation Method 1
a pressure sensor and a temperature sensor which are located adjacent the restrictor to detect and measure changes in air pressure and air temperature adjacent the restrictor
Implementation Method 2
a pressure sensor and a temperature sensor which are located adjacent the restrictor to detect and measure changes in air pressure and air temperature adjacent the restrictor
Implementation Method 3
a restrictor that extends from the second pipe and for restricting the passage of fluid from the second fluid passage before it flows into a breather of the gas turbine engine
Implementation Method 4
a second pipe that houses the first pipe and defines a second fluid passage between the first pipe and the second pipe that is supplied with cooling air
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
An oil pipe assembly (100) for a gas turbine engine (10). The oil pipe assembly includes a first pipe (105) that defines a first fluid passage (110) between an oil supply and a bearing chamber (55), and a second pipe (115) that houses the first pipe and defines a second fluid passage (120) between the first pipe and the second pipe that is supplied with cooling air. The oil pipe assembly also includes a restrictor (140) that extends from the second pipe (115) and restricts the passage of fluid from the second fluid passage (120) before it flows into a breather. Pressure and temperature sensors (150, 155) are located adjacent the restrictor (140) to detect and measure changes in air pressure and air temperature adjacent the restrictor from which a controller (160) identifies whether a leak has occurred in the first pipe or the second pipe. A method for detecting a leak in the oil pipe assembly (100), and a gas turbine (10) are also described.