Bearing Compartment Drainback Layout for Turbine Oil Recirculation
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Solution Overview
Problem
Gas turbine engines face challenges in effectively recirculating lubricant fluid back into bearing compartments, leading to potential lubricant loss and reduced efficiency due to fluid leakage between seals and surfaces.
Innovation Solution
A passageway system is designed to permit fluid drainage back into the bearing compartment, featuring a gutter and conduit arrangement that directs wept flow back into the compartment, with the outlet positioned to leverage the low pressure created by the rotating shaft gear, ensuring fluid recirculation and containment within the compartment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional seal arrangement is used to contain lubricant in the bearing compartment, then fluid containment is improved, but fluid leakage between the seal and rotating surface still occurs导致lubricant loss
Solution Approach 1:
The patent converts the harmful effect of fluid leakage between the seal and rotating surface into a beneficial recirculation system. The gutter collects leaked fluid, and the passageway with outlet positioned at the low-pressure region near the rotating shaft gear outlet directs it back into the bearing compartment, transforming waste lubricant into useful recirculated fluid that maintains lubrication.
Solution Approach 2:
The patent introduces intermediary components (gutter and passageway) between the seal leakage point and the bearing compartment. The gutter acts as a collection intermediary, and the passageway serves as a transport intermediary, facilitating the return of leaked lubricant to its original location without requiring modification of the seal itself.
2Productivity
If the passageway outlet is positioned near the rotating shaft gear outlet where low pressure exists, then fluid recirculation efficiency is improved, but the complexity of the passageway arrangement increases
Solution Approach 1:
The patent employs self-service by positioning the passageway outlet to utilize the existing low-pressure region created by the rotating shaft gear outlet. This pressure differential automatically drives fluid recirculation without requiring additional pumps or active control systems, achieving efficient recirculation while minimizing system complexity.
Solution Approach 2:
The patent changes the spatial parameter of the passageway outlet position to coincide with the low-pressure zone near the rotating shaft gear outlet. This parameter optimization leverages the natural pressure distribution in the system to enhance recirculation efficiency without adding complex control mechanisms.
3Loss of substance
If a gutter and conduit arrangement is added to direct fluid back into the bearing compartment, then lubricant recirculation is improved, but the device complexity increases
Solution Approach 1:
The patent extracts the fluid collection and return function from the main bearing compartment structure, creating a separate gutter and passageway system. This extraction allows the recirculation function to be added independently, improving lubricant retention while keeping the modification to the existing system minimal and modular.
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 recirculates fluid back into the bearing compartment, maintaining lubrication and reducing fluid loss, thereby enhancing the operational efficiency and longevity of the gas turbine engine.
Implementation Method 1
The outlet is positioned to leverage the low pressure created by the rotating shaft gear, ensuring fluid recirculation
Data Source
AI summary
A gas turbine engine according to an exemplary aspect of the present disclosure includes, among other things, a passageway configured to permit fluid to drain back into a bearing compartment. The passageway has an inlet outside the bearing compartment and an outlet inside the bearing compartment. The outlet is spaced-apart from a central rotational axis of a towershaft gear.