Shiftable Transmission for Low-Spool Generator Speed Matching
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Solution Overview
Problem
Modern gas turbine engines face efficiency challenges in power extraction due to the large operating speed range of the low pressure spool, which is not typically utilized for power generation, as it is not compatible with existing generators.
Innovation Solution
A transmission system with multiple gear ratios and clutches is implemented to adjust the rotational speed of the low speed spool's rotational energy to a compatible range for generators, using a geared architecture and clutch lay shafts to engage specific gear ratios, allowing efficient power transfer from the low speed spool to the generator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If power extraction is moved from the high pressure spool to the low pressure spool, then efficiency is improved, but the large operating speed range of the low pressure spool makes it incompatible with existing generators
Solution Approach 1:
A transmission system is introduced as an intermediary between the low pressure spool and the generator. This transmission includes multiple gear ratios (first, second, third, and fourth gear ratios) with corresponding clutches (first, second, third, and fourth clutches) that can selectively engage different gear ratios. The transmission converts the large operating speed range of the low pressure spool into a compatible speed range for the generator, enabling efficient power extraction while maintaining generator compatibility.
2Loss of energy
If a transmission system with multiple gear ratios and clutches is implemented, then power extraction efficiency is improved, but device complexity increases
Solution Approach 1:
The transmission system is segmented into multiple independent gear ratio stages, each with its own clutch control. The gears are arranged in a segmented structure where first and second gears are associated with a first clutch, and third and fourth gears are associated with a second clutch. This segmentation allows selective engagement of different gear ratios based on operating conditions, managing complexity through modular organization.
Solution Approach 2:
The transmission system employs dynamic clutch control to selectively engage different gear ratios based on the operating speed range of the low pressure spool. The clutches can dynamically switch between gear ratios to optimize power extraction efficiency across varying operating conditions, transforming a static complex system into a dynamically adaptable one.
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 enables the efficient transfer of rotational energy from the low speed spool to the generator over a wide range of input speeds, enhancing power extraction efficiency without the need for complex components like one-way clutches or synchromesh arrangements, maintaining consistent torque and simplifying the power transmission process.
Implementation Method 1
A transmission system with multiple gear ratios and clutches is implemented to adjust the rotational speed of the low speed spool's rotational energy to a compatible range for generators
Implementation Method 2
using a geared architecture and clutch lay shafts to engage specific gear ratios, allowing efficient power transfer from the low speed spool to the generator
Data Source
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AI summary
A power transmission (62) includes an input shaft (58), an output shaft (64), and a plurality of gear ratios (66a-d) selectably engagable with the input shaft and the output shaft to transfer rotational energy from the input shaft to the output shaft to drive the output shaft at a selected output shaft speed. A plurality of clutches (74a-d), each clutch is located at a clutch lay shaft (68a,b) of a plurality of clutch lay shafts and is configured to control selective engagement of only one gear ratio of the plurality of gear ratios.