Interdigitated Turbine Rotor Support via Segmented Bearing Frame
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Solution Overview
Problem
Gas turbine engines face limitations in increasing fuel efficiency and power output due to restricted interdigitation of turbine rotors, which leads to inefficiencies such as increased seal interface leakages and adverse rotor dynamics, necessitating a solution to reduce seal interface clearances and unsupported turbine length.
Innovation Solution
A gas turbine engine design featuring a turbine frame with a bearing assembly and spoke structure that allows for interdigitated turbine rotors, reducing seal interface clearances and unsupported length, while improving efficiency through a radial and axial arrangement that includes a first and second turbine rotor assembly with a bearing surface and vane configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If turbine rotors are interdigitated to increase efficiency and power output, then fuel efficiency and power output are improved, but seal interface leakages increase and rotor dynamics deteriorate
Solution Approach 1:
The turbine section is divided into multiple turbine rotors (first turbine rotor and second turbine rotor) that are interdigitated along the axial direction. Each rotor is supported by independent bearing assemblies, segmenting the support structure to manage the complexities of interdigitation while maintaining rotational stability and reducing leakages.
Solution Approach 2:
The patent transitions from a single-plane rotor arrangement to a multi-plane interdigitated configuration along the axial dimension. The first and second turbine rotors are positioned at different axial locations with alternating blade rows, enabling increased power output while using bearing assemblies to control seal clearances and minimize leakages in this new dimensional arrangement.
2Productivity
If turbine rotors are interdigitated to increase efficiency, then fuel efficiency is improved, but rotor dynamics and structural life are adversely affected
Solution Approach 1:
The bearing assembly is segmented into a first bearing assembly supporting the first turbine rotor and a second bearing assembly supporting the second turbine rotor. Each bearing assembly independently manages the rotor dynamics of its respective rotor, allowing for optimized support and reduced vibrations even in the interdigitated configuration.
Solution Approach 2:
The bearing assemblies act as intermediaries between the interdigitated turbine rotors and the turbine frame. They provide the necessary support and constraint to maintain proper rotor alignment and dynamics, mediating the forces and movements to prevent adverse effects on rotor stability and structural life.
3Productivity
If interdigitation is increased to improve efficiency, then power output is improved, but seal interface clearances increase causing more leakages
Solution Approach 1:
The turbine frame includes multiple bearing assemblies positioned at different axial locations to support the interdigitated rotors. This segmentation of the support structure reduces the unsupported axial length between bearing supports, thereby reducing seal interface clearances and minimizing leakages while still allowing for interdigitation to improve efficiency.
Data Source
AI summary
The present disclosure is directed to a gas turbine engine defining a radial direction, a circumferential direction, an axial centerline along a longitudinal direction, and wherein the gas turbine engine defines an upstream end and a downstream end along the longitudinal direction, and wherein the gas turbine engine defines a core flowpath extended generally along the longitudinal direction. The gas turbine engine includes a turbine frame defined around the axial centerline, the turbine frame comprising a first bearing surface disposed inward along the radial direction. The gas turbine engine further includes a turbine rotor assembly including a bearing assembly coupled to the first bearing surface of the turbine frame and the turbine rotor assembly. The turbine rotor assembly further includes a first turbine rotor disposed upstream of the turbine frame and a second turbine rotor disposed downstream of the turbine frame. The first turbine rotor and the second turbine rotor are rotatable together about the axial centerline.