Gas Turbine Accessory Mounting Frame Vibration Isolation
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Solution Overview
Problem
Conventional accessory mounting arrangements in gas turbine engines face challenges such as increased weight, drag, and adverse specific fuel consumption due to the location of accessory gearboxes within the outer nacelle, and direct mounting to the engine core leads to premature failure from inertia, vibration, and thermal loads.
Innovation Solution
An accessory mounting frame that provides a direct load path between the accessory and engine mount points, using anti-vibration mounts and jointed struts to isolate accessories from engine vibrations and thermal loads, allowing for independent mounting of accessories closer to the engine core without direct transfer of loads, and utilizing a modular design to optimize space utilization and reduce weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If accessories are mounted directly to the engine core, then space utilization is improved and weight is reduced, but reliability deteriorates due to vibration and thermal load transfer
Solution Approach 1:
The patent introduces a mounting frame as an intermediary structure between the accessory and the engine core. This frame is independently mounted to the engine case and provides a vibration-isolated mounting point for the accessory, thereby preventing direct transmission of vibrations and thermal loads to the accessory while maintaining close proximity to the engine core.
Solution Approach 2:
The mounting system is segmented into independent components: the mounting frame is separately mounted to the engine case, and the accessory is mounted to the frame. This segmentation allows the frame to act as a vibration isolation platform, decoupling the accessory from direct engine vibrations and thermal effects.
2Reliability
If accessory gearboxes are located within the outer nacelle, then reliability is improved by keeping them away from hot environment, but weight and drag increase due to increased nacelle diameter
Solution Approach 1:
The patent moves the accessory gearbox from the conventional outer nacelle location to an inner nacelle position, utilizing the radial space closer to the engine core. The mounting frame extends radially outward from the engine case, allowing the gearbox to be positioned in the inner nacelle volume without increasing the overall nacelle diameter, thereby reducing weight and drag while maintaining thermal isolation.
3Weight of moving object
If accessories are mounted closer to the engine core, then weight is reduced, but thermal load transfer to accessories increases
Solution Approach 1:
The mounting frame serves as a thermal intermediary structure. By being independently mounted to the engine case and positioned in the inner nacelle, it provides a mounting location close to the engine core while physically separating the accessory from direct exposure to high-temperature exhaust gases and thermal radiation, thereby reducing thermal load transfer.
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
This solution reduces the transfer of vibrations and thermal loads to accessories, minimizes weight and drag, and allows for more efficient cooling and maintenance access, while potentially reducing the overall weight of the engine by allowing accessories to be located closer to their point of use, thereby improving reliability and reducing specific fuel consumption.
Implementation Method 1
anti-vibration mounts for damping vibration are provided between the frame and the front and/or rear mount
Implementation Method 2
The frame comprises at least one jointed strut for absorbing axial movement of the frame relative to the front and rear mount points
Data Source
AI summary
Accessories are mounted to a gas turbine engine from a frame attached to a pylon which is used to mount the engine to an airframe. The frame independently mounts the accessories so that engine vibrations are not transmitted to the accessories.