Annular Element Varies Turbine Nozzle Throat Section

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Solution Overview

Problem

Existing turbine nozzle throat section variation systems rely on small, high-risk hinging parts that are difficult and costly to assemble and maintain, prone to seizing and erosion in the hot nozzle environment.

Innovation Solution

A device using an annular element with a lower coefficient of expansion than the nozzle platforms, secured to the outer platform, which moves radially to vary the throat section without hinges, allowing for easy assembly and reliable operation by leveraging temperature differences between turbomachine stages.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If hinged systems with flaps and pivots are used to vary the throat section, then the throat section can be reduced to increase pumping margin, but the device becomes complex and unreliable in hot environments

Engineering Contradiction:

ImprovereliabilityVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates the hinged parts (pivots, cranks, control rings) from the system. Instead of using a complex hinged mechanism to vary the throat section, the patent uses a simple annular element that relies on the natural thermal expansion of the nozzle platforms to move radially and control the flow passage area.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The annular element is designed to move automatically based on the thermal expansion of the nozzle platforms. The element's radial position is determined by the expansion state of the platforms, eliminating the need for external control mechanisms or powered actuators. The system uses the thermal environment itself to control the throat section variation.

Inventive Principle:

Principle #25Self-service

2Reliability

If small hinged parts are used in the nozzle zone, then the throat section can be varied, but the parts are prone to seizing, burning, and erosion in the hot environment

Engineering Contradiction:

Improveresistance to seizing and erosionVSAvoidexposure to hot environment

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The annular element is designed as a simple, robust component without small moving parts that are susceptible to damage. While not literally disposable, the design philosophy replaces fragile, hard-to-replace hinged parts with a durable element that can withstand the hot environment and is easier to replace if needed.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The invention replaces the mechanical hinged system with a thermal-mechanical system. Instead of using powered actuators and mechanical linkages to move the throat section, the system uses the natural thermal expansion of the nozzle platforms to drive the annular element radially, eliminating the need for complex mechanical drive mechanisms in the hot environment.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If hinged vane systems are used to reduce the flow section, then the throat section can be varied, but assembly and maintenance become difficult and expensive

Engineering Contradiction:

Improveease of assembly and maintenanceVSAvoidnumber of parts

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The invention segments the throat section control function from the overall nozzle structure. The annular element is a separate, standalone component that can be independently manufactured and installed. This segmentation allows for simpler assembly and maintenance compared to integrated hinged vane systems, as the annular element can be accessed and replaced without disassembling the entire nozzle.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The annular element serves multiple functions: it controls the throat section area, maintains structural integrity in the hot environment, and automatically responds to thermal conditions. This multi-functionality reduces the need for additional components and simplifies the overall device design, making assembly and maintenance easier.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

The solution provides a reliable, low-maintenance, and cost-effective means to vary the nozzle throat section, reducing the flow passage area by up to 4% during non-idling stages, enhancing turbomachine performance and reducing specific consumption.

Implementation Method 1

an annular element (24) having a coefficient of expansion that is less than that of the platforms (18, 20) of the nozzle

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS7553126B2Device for varying the section of the throat in a turbine nozzle

Publication Date: 2009.06.30 SAFRAN AIRCRAFT ENGINES SAS

AI summary

A device for varying the section of the throat of a turbine nozzle, the nozzle being formed by a plurality of stationary vanes extending radially between outer and inner annular platforms and spaced apart from one another in order to define a throat presenting a minimum flow section. The device comprises an annular element having a coefficient of expansion that is less than that of the platforms of the nozzle, the annular element being secured to the outer platform and being capable of taking up two positions: one position corresponding to no expansion of the platforms, in which the element provides continuity for the profile of the flow passage; and another position corresponding to the platforms having expanded, in which position the element projects into the flow passage so as to reduce its section.