Low-Spool Transmission with Selectable Gear Ratios for Power Extraction
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Solution Overview
Problem
Modern gas turbine engines face inefficiencies in power extraction due to the large operating speed range of the low pressure spool, which is not typically used for mechanical energy conversion, limiting the ability to transfer rotational energy effectively to generators for electrical power generation.
Innovation Solution
A power transmission system with multiple gear ratios and clutches is implemented, allowing selective engagement of gear ratios to match the output shaft speed to the generator's requirements, using a secondary shaft for energy transfer between clutch lay shafts and the output shaft, ensuring rotational energy is transferred within a usable range of 8000 rpm to 16000 rpm.
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 difficult to maintain consistent rotational energy transfer
Solution Approach 1:
The transmission system dynamically adapts to the varying operating speeds of the low pressure spool by providing multiple selectable gear ratios. This allows the system to optimize the rotational speed match between the low pressure spool and the generator across different operating conditions, maintaining efficient energy transfer despite the wide speed range of the low pressure spool.
Solution Approach 2:
The system changes the transmission ratio parameter by selecting different gear ratios through the clutch mechanism. This allows the rotational speed relationship between the low pressure spool and generator to be adjusted according to operating conditions, enabling efficient power extraction across the entire operating speed range of the low pressure spool.
2Productivity
If multiple gear ratios are selectably engaged to match output shaft speed to generator requirements, then power extraction efficiency is improved, but system complexity increases
Solution Approach 1:
The transmission system is segmented into discrete gear ratios that can be independently selected through individual clutches. This segmentation allows the system to provide multiple fixed transmission ratios without requiring complex continuous variable transmission mechanisms, simplifying the overall system while maintaining the ability to optimize for different operating conditions.
Solution Approach 2:
The clutch mechanism acts as an intermediary that selectively engages different gear ratios. This simple on/off switching mechanism enables the system to switch between multiple transmission ratios without complex control systems, maintaining ease of operation while achieving efficient power extraction across various operating speeds.
3Power
If the low pressure spool is used for power extraction, then mechanical energy conversion capability is improved, but the large speed range variation makes consistent torque transfer difficult
Solution Approach 1:
The transmission system dynamically adjusts the gear ratio selection based on operating conditions to maintain optimal torque transfer. By selecting appropriate gear ratios for different speed ranges, the system compensates for the low pressure spool's speed variations and maintains consistent torque delivery to the generator.
Solution Approach 2:
The system changes the transmission ratio parameter in response to varying operating speeds. This parameter adjustment compensates for the speed range variation of the low pressure spool, ensuring that torque is transferred consistently to the generator regardless of the instantaneous speed of the low pressure spool.
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 configuration enables efficient power extraction from the low pressure spool, allowing for effective rotational energy conversion to electrical power, simplifying the system by eliminating the need for additional components like one-way clutches or synchromesh arrangements, and maintaining consistent torque.
Implementation Method 1
a plurality of gear ratios selectably engagable with the input shaft and the output shaft to transfer rotational energy from the input shaft to the output shaft
Implementation Method 2
A plurality of clutches, each clutch located at a clutch lay shaft of a plurality of clutch lay shafts and is configured to control selective engagement of only one gear ratio
Implementation Method 3
a secondary shaft is located between the plurality of clutch lay shafts and the output shaft and is configured to transfer rotational energy between the plurality of clutch lay shafts and the output shaft
Data Source
AI summary
A power transmission includes an input shaft, an output shaft, and a plurality of gear ratios 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, each clutch is located at a clutch lay shaft 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.