Differential Geared Generator for Hybrid Gas Turbine Spool Power Transfer
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Solution Overview
Problem
Gas turbine engines operate at peak efficiency during takeoff or climb conditions, leading to lower efficiencies during other modes due to turbine inlet temperature limitations, necessitating hybrid engine designs for enhanced operation.
Innovation Solution
A power extraction and amplification system using a differential geared generator to transfer power between spools, incorporating motors and generators to enhance power distribution and efficiency across various engine components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the gas turbine engine is designed for peak efficiency during takeoff or climb conditions with maximum thrust output, then the turbine inlet temperature approaches its maximum allowable limit for highest efficiency, but the engine operates at lower efficiencies during other modes such as cruise where the turbine inlet temperature is below the maximum allowable limit
Solution Approach 1:
The engine is divided into two independent spool systems (high spool and low spool) that can operate semi-independently. The low spool can extract power and drive a generator to produce electricity, which can then be used to drive a motor on the high spool. This segmentation allows each spool to operate at its optimal efficiency point regardless of the other, resolving the contradiction between peak power output and energy efficiency during different operational modes
Solution Approach 2:
An electrical power system acts as an intermediary between the low spool and high spool. The low spool drives a generator that converts mechanical energy to electrical energy, which then drives a motor on the high spool to convert electrical energy back to mechanical energy. This intermediary system allows efficient power transfer and enables the engine to maintain high efficiency during cruise conditions while still achieving maximum thrust when needed
2Loss of energy
If power is extracted from the low spool to drive the high spool during cruise conditions, then engine efficiency is improved, but the complexity of the power transmission system increases
Solution Approach 1:
The patent replaces direct mechanical power transmission between spools with an electrical power transmission system. Instead of using complex mechanical gear systems or shafts to transfer power from the low spool to the high spool, the invention uses a generator to convert mechanical energy to electrical energy, which is then used by a motor to drive the high spool. This substitution simplifies the overall power transmission system while maintaining high efficiency during cruise conditions
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
Enhances engine efficiency by amplifying power output and redistributing it effectively across spools, improving performance across different operational modes.
Implementation Method 1
a differential gear assembly including a first input shaft, a second input shaft, a ring gear, a plurality of planet gears, a carrier, and an output shaft
Implementation Method 2
The low spool tower shaft is coupled to a differential gear box. The differential gear box is connected to a generator
Implementation Method 3
The generator is connected to a motor that is connected to the high speed spool
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A power extraction and amplification system (200; 400; 500; 600; 700) for a gas turbine engine (20) is disclosed. In various embodiments, the power extraction and amplification system (200; 400; 500; 600; 700) includes a low spool tower shaft (204; 404; 504; 604) configured for engagement with a low speed spool (30), a high spool tower shaft (202; 402; 502; 602) configured for engagement with a high speed spool (32), a first motor (242; 442; 542; 642), a generator (266; 466; 566; 666), a differential gear box operably coupled to the low spool tower shaft (204; 404; 504; 604), to the first motor (242; 442; 542; 642) and to the generator (266; 466; 566; 666), and a second motor (270; 470; 570; 670) operably coupled to the generator (266; 466; 566; 666) and the high spool tower shaft (202; 402; 502; 602).