Asymmetric Engine Operation for In-Flight Performance Testing
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Solution Overview
Problem
Maintaining stable engine performance during in-flight tests of gas turbine engines is challenging due to variations in flight conditions, making it difficult to obtain valid data for assessing engine health and ensuring long-term engine health.
Innovation Solution
The method involves operating a first engine at a low power level in an output speed governing mode and a second engine at a higher power level in a core speed governing mode, allowing the second engine to maintain thermodynamic stability while performing an engine performance test, and transitioning between asymmetric operating regimes to optimize fuel efficiency and power distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an engine performance test is conducted during flight, then engine health assessment is improved, but stable operating conditions deteriorate due to flight condition variations
Solution Approach 1:
The patent divides the engine testing function into two distinct modes: a first engine operates in output speed governing mode while a second engine operates in core speed governing mode. This segmentation allows one engine to maintain stable thermodynamic conditions for testing while the other adapts to flight condition variations, thereby resolving the contradiction between measurement precision and operating stability.
Solution Approach 2:
The patent changes the governing mode parameter from traditional single-mode operation to dual-mode operation. By transitioning one engine to core speed governing mode (as opposed to output speed governing), the system achieves thermodynamic stability suitable for precise performance measurement while maintaining overall flight operation flexibility.
2Measurement precision
If one engine operates at high power level for testing, then test data accuracy is improved, but fuel consumption increases
Solution Approach 1:
The patent implements asymmetric engine operation where one engine (the second engine) operates at a higher power level in core speed governing mode to provide stable test data, while the other engine (the first engine) operates at a lower power level in output speed governing mode. This asymmetric configuration allows accurate testing to be performed on one engine while the other engine compensates by operating efficiently, thereby reducing overall fuel consumption compared to running both engines at high power.
3Use of energy by moving object
If dual-engine asymmetric operation is implemented, then fuel efficiency is improved, but system complexity increases
Solution Approach 1:
The patent makes both engines capable of operating in multiple governing modes. Each engine can function in either output speed governing mode or core speed governing mode, providing multi-functionality. This universality allows the system to achieve fuel-efficient asymmetric operation without requiring additional specialized equipment, as the existing engines can adapt to different operational roles based on testing requirements.
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
Systems and methods (300) for testing engine performance in-flight in an aircraft (1) having a first engine (10A) and a second engine (10B) comprise operating the first engine (10A) at a first power level in an output speed governing mode, operating the second engine (10B) at a second power level greater than the first power level in a core speed governing mode concurrently with the first engine (10A) operating at the first power level in the output speed governing mode, and performing an engine performance test on the second engine (10B) while the second engine (10B) is at the second power level in the core speed governing mode.