Variable Area Turbine Transition Duct Airflow Alignment
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Solution Overview
Problem
Gas turbine engines face incidence angle variation issues due to fixed flow areas in turbine sections, which can lead to inefficiencies in energy extraction and component exposure.
Innovation Solution
A variable area turbine arrangement is implemented, featuring a transition duct with stationary vanes positioned upstream of variable vanes to align airflow with desired inlet angles, reducing incidence angle variation by straightening and channeling core airflow between sloped portions of the transition duct.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If variable vanes are used to alter flow area, then energy extraction efficiency is improved, but incidence angle variation increases causing downstream component exposure to flow angle changes
Solution Approach 1:
A transition duct with stationary vanes is introduced as an intermediary component between the first and second turbine sections. The stationary vanes in the transition duct act as a mediator that redirects and straightens the airflow, ensuring that the flow angle entering the second variable vane row remains within the desired inlet angle range, thereby reducing incidence angle variation while preserving the benefits of variable flow area control
Solution Approach 2:
The transition duct with stationary vanes performs preliminary airflow conditioning before the flow reaches the second variable vane row. By pre-aligning the airflow angles in advance, the system ensures that when the second variable vanes adjust the flow area, the incidence angle variation at their inlets is minimized, allowing efficient energy extraction without exposing downstream components to harmful flow angle changes
2Ease of manufacture
If fixed flow area is used in turbine sections, then manufacturing simplicity is maintained, but energy extraction efficiency is reduced due to inability to optimize for different flight points
Solution Approach 1:
The turbine system incorporates variable vanes in both the first and second turbine sections that can dynamically adjust the flow area. This dynamic capability allows the turbine to optimize energy extraction for different flight conditions and operating points, significantly improving productivity while the transition duct with stationary vanes ensures these adjustments are made without causing harmful incidence angle variations
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 arrangement enhances energy extraction efficiency and reduces incidence angle variations, improving the operational stability and performance of gas turbine engines by optimizing airflow alignment and flow area adjustments.
Implementation Method 1
The transition duct may include at least one stationary vane configured to reduce the onset of inlet incidence angle variation at the variable vanes of the second turbine section
Data Source
Figure 1
Figure 2~3
AI summary
A variable area turbine arrangement according to an exemplary aspect of the present disclosure includes, among other things, a first turbine section having at least a first variable vane row and a second turbine section downstream from the first turbine section and having at least a second variable vane row. A transition duct is disposed between the first turbine section and the second turbine section.