Threaded Fitting for Gas Turbine Bearing Lubricant Isolation
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Solution Overview
Problem
Gas turbine engine lubricant transport systems face challenges in maintaining fluid path separation and heat management, leading to issues like coking and blocked passageways due to excessive heating, which affects the performance and reliability of bearing systems.
Innovation Solution
A tubing assembly with a multiwall tube configuration and fittings that form an interference fit, allowing for fluid isolation between inner and outer fluid paths, and a mid-turbine frame with a bearing damper, which includes a bearing compartment and fluid paths to manage heat transfer and prevent fluid mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a double wall tube is used to transport lubricant, then heat management is improved, but fluid separation becomes difficult to maintain at the exit
Solution Approach 1:
The fitting is segmented into distinct sealing surfaces: a first sealing surface that seals the inner fluid passage and a second sealing surface that seals the outer fluid passage. This segmentation allows independent sealing of each fluid path, maintaining fluid separation even at the exit where heat management requirements are critical.
Solution Approach 2:
The fitting acts as an intermediary component between the double wall tube and the bearing housing, providing sealed connections for both inner and outer fluid passages. The fitting's dual sealing surfaces prevent fluid mixing while allowing heat transfer management through the tube structure.
2Ease of manufacture
If conventional tubing assemblies are used, then assembly is simple, but fluid path isolation is insufficient under high temperature conditions
Solution Approach 1:
The fitting incorporates separate sealing surfaces for inner and outer fluid passages, with each sealing surface independently configured to prevent fluid leakage. This segmentation ensures reliable fluid path isolation even when subjected to high temperatures that could compromise conventional single-seal designs.
Solution Approach 2:
Different portions of the fitting have specialized sealing surfaces optimized for their specific functions: the first sealing surface is configured for the inner fluid passage while the second sealing surface is configured for the outer fluid passage. This local quality differentiation ensures appropriate sealing performance in each region under high temperature conditions.
3Temperature
If oil is subjected to excessive heating, then cooling efficiency is improved, but coking occurs causing blocked passageways
Solution Approach 1:
The sealed fluid passages in the fitting prevent oil from being exposed to excessive heating conditions that would cause coking. By maintaining proper thermal boundaries and preventing fluid contamination, the design converts the potential harm of heat exposure into beneficial controlled thermal management, keeping oil temperatures in the optimal range for lubrication without degradation.
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 isolates fluid paths and reduces heat transfer, preventing coking and maintaining fluid separation, thus enhancing the reliability and performance of gas turbine engine bearing systems by ensuring efficient lubricant delivery and heat management.
Implementation Method 1
The first mating surface of the fitting contacts the second mating surface of the bearing housing to form an interference fit in response to rotating the fitting within the bearing housing
Data Source
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AI summary
A tubing assembly (100) for fluid delivery to a bearing system (38) may comprise a fitting (104) having an inner surface (164) defining an inner flow path (160) and having an outer surface (166) defining a first mating surface (170). A first tube (112) may be coupled to the fitting (104). The fitting (104) may be disposed within a bearing housing (78) of the bearing system (38). The bearing housing (78) may include a second mating surface (176) in sealing contact with the first mating surface (170) of the fitting (104).