Variable Cycle Gas Turbine Engine Common Flow Path
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Solution Overview
Problem
Conventional three-stream gas turbine engine architectures are complex and heavy, which can negate the performance benefits for missions with varying requirements, such as supercruise and loiter, due to increased complexity and weight penalties.
Innovation Solution
A variable cycle gas turbine engine design featuring a core flow path with a common flow path that directs two separate streams, each operating at different total temperatures and pressures, utilizing span-adaptive stators with rotatable segments and flaps to control airflow, and circumferential partial span shrouds to segregate and control the streams, reducing the need for additional turbomachinery and inter-stream ducts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional three-stream gas turbine engine architecture is used to achieve variable cycle operation with different total temperatures and pressures, then aircraft performance for missions with varying requirements is improved, but device complexity and weight increase
Solution Approach 1:
The patent combines two separate outer streams into a single common flow path, allowing both streams to co-exist and be directed through the same physical ducting. This merging approach maintains the ability to operate with different total temperatures and pressures while eliminating the need for separate ducts and reducing overall system complexity
Solution Approach 2:
The common flow path serves multiple functions by accommodating both the second stream and third stream simultaneously. The flow path is designed to handle different flow conditions (different total temperatures and pressures) within the same structural framework, reducing the need for specialized components for each stream
2Adaptability or versatility
If a conventional three-stream gas turbine engine architecture is used to achieve variable cycle operation with different total temperatures and pressures, then aircraft performance for missions with varying requirements is improved, but weight increases
Solution Approach 1:
By merging the second and third streams into a common flow path, the patent eliminates duplicate ducting, supports, and structural components that would be required for completely separate stream paths. This consolidation directly reduces the overall engine weight while maintaining the capability for variable cycle operation
Solution Approach 2:
The common flow path is designed as a multi-functional structure that can accommodate different stream conditions without requiring separate specialized infrastructure. This universal approach reduces the total material required and consequently reduces engine weight
3Adaptability or versatility
If span-adaptive stators with rotatable segments and flaps are used to control airflow in the common flow path, then airflow characteristics are adjusted for different mission requirements, but device complexity increases
Solution Approach 1:
The stators are divided into multiple spanwise segments that can be independently controlled. This segmentation allows different portions of the flow path to be adjusted independently, enabling precise control over airflow characteristics for different mission requirements while keeping each individual segment relatively simple in design
Solution Approach 2:
The stators incorporate rotatable segments and flaps that can dynamically adjust their orientation to control airflow. This dynamic capability allows the engine to adapt to different operating conditions (supercruise, loiter, etc.) by changing the flow direction and distribution without requiring complete redesign of the vane array
Data Source
AI summary
A gas turbine engine is provided that includes a core flow path to direct a core stream flow. A common flow path is outboard of the core flow path, where the common flow path directs both a second stream flow and a third stream flow. Another gas turbine engine is provided that includes an outer case structure around a central longitudinal engine axis. An intermediate case structure is inboard of the outer case structure, where the intermediate case structure and the outer case structure direct both a third stream flow and a second stream flow. An inner case structure is inboard of the intermediate case structure, where the inner case structure and the intermediate case structure direct a core stream flow.