Separator Nozzle Guide Vanes for Variable-Cycle Turbine Flow Control
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Solution Overview
Problem
Conventional turbomachines face challenges in incorporating variable-pitch stator blades due to space constraints, leading to increased axial length and mass, and noise pollution issues, which are unsuitable for multiflow and variable-cycle operations.
Innovation Solution
Incorporating variable-pitch rectifier blades at the separator nozzle with fixed stator blades in the outer secondary flow, minimizing axial distance and using a control system for angular displacement, while maintaining small clearances to limit gas leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If variable-pitch stator blades are incorporated in conventional turbomachines, then gas flow control capability is improved, but axial length and mass increase
Solution Approach 1:
The patent merges the variable-pitch stator blades with the separator nozzle structure, where the stator blades are integrated directly into the nozzle body. This integration eliminates the need for separate mounting structures and reduces the axial space required, resolving the contradiction between improved gas flow control capability and increased axial length.
Solution Approach 2:
The patent positions the variable-pitch stator blades at the separator nozzle location, utilizing the radial and circumferential dimensions of the nozzle structure to accommodate the blades. By leveraging the three-dimensional space of the nozzle rather than adding axial length, the design achieves variable pitch capability without proportionally increasing the overall axial dimension of the turbomachine.
2Adaptability or versatility
If variable-pitch stator blades are incorporated in conventional turbomachines, then gas flow control capability is improved, but mass increases
Solution Approach 1:
The patent combines the variable-pitch stator blades with the separator nozzle into a single integrated structure. This merging eliminates redundant materials and fastening components that would otherwise be required, reducing the overall mass while maintaining the variable pitch functionality for improved gas flow control.
Solution Approach 2:
The separator nozzle structure serves multiple functions: it separates the main gas flow into secondary flows and simultaneously houses the variable-pitch stator blades. This multi-functionality reduces the need for additional dedicated components, thereby reducing overall mass while achieving improved gas flow control capability.
3Length of moving object
If stator blade is brought closer axially to rotor blade, then axial length is reduced, but noise pollution increases
Solution Approach 1:
The patent reduces axial length by utilizing the radial and circumferential space at the separator nozzle rather than simply compressing the axial distance between rotor and stator blades. The variable-pitch blades are positioned at the nozzle where they can effectively control flow while maintaining adequate spacing from the rotor blades, thus reducing overall axial length without significantly increasing noise.
4Ease of operation
If clearances between nozzle and separator are increased, then variable-pitch blade movement is facilitated, but gas leakage increases
Solution Approach 1:
The patent applies different clearance characteristics to different regions: larger clearances are provided where needed for blade movement, while smaller clearances are maintained in critical areas to prevent gas leakage. This localized differentiation of clearance quality allows the system to achieve both ease of operation and minimal gas loss.
Solution Approach 2:
The patent optimizes the clearance parameters between the variable-pitch blades and the nozzle/separator structures. By carefully selecting and adjusting these dimensional parameters, the design achieves sufficient clearance for smooth blade operation while maintaining tight enough clearances to minimize gas leakage, thus resolving the contradiction between ease of operation and substance loss.
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
Optimizes turbomachine operation for multiflow and variable-cycle applications by reducing axial length and mass, while minimizing noise and gas leakage, enabling efficient gas flow adjustments.
Implementation Method 1
an annular separator 24 is disposed between the two walls 12, 14 and defines respectively with these walls 12, 14 two secondary annular flow ducts, respectively internal 26 and external 28, of the secondary gas streams 20, 22. This separator 24 has at an upstream end an annular nozzle 24a configured to divide the main gas stream 18 into two and form the secondary gas streams 20, 22.
Data Source
Figure 1a~1b
Figure 2a~2b
Figure 3a~3c
AI summary
Aircraft turbine engine (10) comprising: - two coaxial annular walls defining between them a main annular duct (16) for the flow of a primary airflow (18); - a rotor blading (30) extending radially through the first duct (16); - an annular separator (24) arranged downstream of the rotor blading (30) and configured to divide the primary airflow (18) into two to form the secondary air flows (20, 22); - first variable guide vanes (40) which are distributed around the shaft and each comprise a leading edge (40a) which is located upstream of the separator (24) and trailing edges (40b, 40c) which are located in the secondary airflows (20, 22); - and fixed guide vanes (42) which are distributed around the shaft in the external airflow and downstream of the first variable vanes (40).