Variable Area Turbine Nozzle Segmented Vane Actuation
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Solution Overview
Problem
Existing gas turbine engines face challenges in achieving variable flow through turbine nozzles due to severe temperature and pressure conditions, leading to mechanical and aerodynamic inefficiencies, reduced structural integrity, and difficulty in maintaining accurate throat areas for optimal performance.
Innovation Solution
A variable area turbine nozzle system with outer and inner bands and pivotable vane segments, utilizing two actuating systems to adjust the throat area and trailing edge segments, allowing for precise control of combustion gas flow while minimizing efficiency penalties and structural stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If pivotable nozzle vanes are used to achieve variable flow area, then flow variability is improved, but structural integrity and durability deteriorate due to increased degree of freedom and bending loads
Solution Approach 1:
The nozzle vane is divided into multiple segments (first vane segment, second vane segment, trailing edge segment) that can pivot relative to each other. This segmentation allows the vane to achieve variable flow area while distributing mechanical stresses across multiple joints and segments, improving overall structural reliability compared to a single-piece pivotable vane.
Solution Approach 2:
The invention employs dynamically adjustable vane segments that can change their relative positions through controlled pivoting. The first and second actuating systems enable dynamic adjustment of throat area and trailing edge position, allowing the nozzle to adapt flow characteristics while maintaining structural integrity through controlled movement rather than rigid rotation.
2Measurement precision
If individual vane pivoting is implemented for variable throat area, then flow control precision is improved, but actuation torque and bending loads increase to unacceptable levels
Solution Approach 1:
Instead of pivoting individual vanes about their own centers (which creates large bending moments), the invention introduces a second degree of freedom by allowing segments to pivot at specific locations along the vane length. The first actuating system pivots the second vane segment relative to the first, while the second actuating system pivots the trailing edge segment, distributing the actuation forces across multiple dimensions and reducing required torque.
Solution Approach 2:
The first and second actuating systems serve as intermediaries between the control system and the vane segments. These actuating systems are positioned to optimize the mechanical advantage, reducing the actuation torque required to achieve precise throat area control while minimizing bending loads on the vane structure.
3Temperature
If nozzle vanes are cooled in severe temperature environment, then thermal stress is reduced, but hub and tip gaps require sealing which complicates design
Solution Approach 1:
The vane is segmented into multiple sections (first vane segment, second vane segment, trailing edge segment) with defined interfaces. This segmentation allows for integrated sealing solutions at each segment interface, where cooling passages can be terminated and sealed locally rather than requiring complex through-vane sealing, reducing overall design complexity while maintaining thermal management.
Data Source
AI summary
The present disclosure is directed to a variable area turbine nozzle. The variable area turbine nozzle includes a first vane segment, a second vane segment arranged with the first vane segment, and a trailing edge segment arranged with the first and second vane segments. The vane also includes a first actuating system for pivoting the second vane segment with respect to the first vane segment and a second actuating system for pivoting the trailing edge with respect to the first and second vane segments.