Coaxial Starter-Generator Layout for Dual-Mode Turbine Engine Starting
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Solution Overview
Problem
Existing turbine engine starting systems face limitations in supporting dual modes of operation and accommodating both high torque and high speed loads, as well as providing sufficient electrical power, due to the design constraints of auxiliary gearboxes and their components.
Innovation Solution
A dual mode starter generator system comprising a first starter, such as an electric starter-generator, and a second starter, such as an air turbine starter, which are coaxially or radially positioned and coupled to a single gearbox input shaft, allowing for independent operation in different modes to address the limitations of existing systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single starter is used in existing turbine engine starting systems, then the system structure is simple, but it cannot support dual modes of operation or provide both high torque and high speed loads simultaneously
Solution Approach 1:
The starting system is segmented into two independent starters (first starter and second starter), each capable of operating independently to provide different starting modes. This segmentation allows the system to support both high torque and high speed starting requirements simultaneously while maintaining structural organization through the common gearbox connection.
Solution Approach 2:
The common gearbox is designed with a universal input shaft that can accept torque from either the first starter or the second starter independently. This multi-functionality allows the same gearbox structure to accommodate dual mode operation without requiring separate gearbox units for each starter type.
2Power
If starters are positioned away from the gearbox to accommodate both high torque and high speed loads, then sufficient torque and electrical power can be provided, but the axial extension and bending moments on the gearbox increase
Solution Approach 1:
The second starter is positioned coaxially with the first starter, creating a nested or concentric arrangement where both starters share the same axial space. This nesting allows both high torque and high speed starters to be accommodated within a compact axial envelope, reducing the overall axial extension of the gearbox while maintaining sufficient power output capability.
3Productivity
If the auxiliary gearbox is redesigned to accommodate dual mode starters, then better performance can be achieved, but manufacturing costs and complexity increase
Solution Approach 1:
The gearbox is designed with a universal input shaft and common mounting structure that can accommodate either the first starter or the second starter independently. This universality allows the same gearbox design to support dual mode operation without requiring separate gearbox units, thereby maintaining ease of manufacture while achieving improved starting system efficiency.
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
Enables efficient dual-mode starting of turbine engines without the need for redesigning or changing the auxiliary gearbox, providing sufficient torque and electrical power generation while reducing the axial extension and bending moments on the gearbox.
Implementation Method 1
a first starter, such as an electric starter-generator
Implementation Method 2
a second starter, such as an air turbine starter
Data Source
AI summary
A system for starting a turbine engine is provided. The system may comprise a gearbox, a first starter, and a second starter. The gearbox may have an gearbox input shaft. The gearbox input shaft may be rotationally coupled to a spool of the turbine engine. The first starter may have a first-starter shaft. The second starter may have a second-starter shaft. The second-starter shaft may be coaxial with the first-starter shaft. The first starter and the second starter may each be coupled to the gearbox input shaft independently of one another.