High-Pressure Turbine Vane Support Decoupling

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Solution Overview

Problem

The radial clearances between the movable blades of the impeller and the ring sectors in a high-pressure turbine turbomachine vary randomly due to axial pressure from hot gases, leading to performance deterioration.

Innovation Solution

An annular metal sheet with an axial groove at its radially inner portion to receive a cylindrical rim of the combustion chamber's outer wall, and a radially outer portion with orifices for ventilation air, is used to sustain forces applied to the upstream guide vane element independently of the ring sectors' support, preventing transmission of these forces to the ring sectors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the upstream guide vane element is pushed downstream by axial pressure from hot gases, then the force is sustained by the annular support of ring sectors, but this causes random variations in radial clearances between impeller blades and ring sectors

Engineering Contradiction:

Improveaxial pressure forceVSAvoidradial clearance

Core Design Contradiction:

ForceVSManufacturing precision

Solution Approach 1:

The system is divided into two independent support structures: one for the upstream guide vane element (fixed element) and one for the ring sectors (annular support). This segmentation isolates the force paths, preventing force transmission from the guide vane to the ring sectors that would cause clearance variations.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The force-sustaining function for the upstream guide vane element is extracted from the annular support structure and assigned to a separate fixed element. This removes the harmful coupling between guide vane forces and ring sector positioning, eliminating the source of radial clearance variations.

Inventive Principle:

Principle #2Taking out (Extraction)

2Productivity

If radial clearances are minimized to improve turbomachine performance, then efficiency increases, but friction and wear between impeller blade ends and ring sectors increases

Engineering Contradiction:

Improveturbomachine performanceVSAvoidblade wear

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

Instead of relying on precise manufacturing and rigid constraints to maintain clearances, the invention allows controlled clearance variations by decoupling the force paths. This inverted approach prioritizes reliability over minimal clearance, accepting slightly larger clearances to prevent wear.

Inventive Principle:

Principle #13The other way round (Inversion)

3Stability of the object's composition

If the upstream guide vane element is rigidly connected to the annular support, then structural stability is improved, but force transmission causes uncontrolled variations in radial clearances

Engineering Contradiction:

Improvestructural stabilityVSAvoidradial clearance control

Core Design Contradiction:

Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

A fixed element acts as an intermediary between the upstream guide vane element and the stationary structure. This mediator absorbs and sustains the axial forces, preventing their transmission to the ring sectors while maintaining the stability of both components through independent support paths.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS8133018B2High-pressure turbine of a turbomachine

Publication Date: 2012.03.13 SAFRAN AIRCRAFT ENGINES SAS

AI summary

A high-pressure turbine of a turbomachine, including at least one upstream guide vane element and an impeller mounted so as to rotate inside ring sectors attached to an annular support which is suspended from an outer casing, the upstream guide vane element including, at its radially inner end, a mechanism for attachment to an inner casing and, at its radially outer end, a mechanism for pressing axially on a fixed element of the turbine that is suspended from the outer casing independently of the annular support for attachment of the ring sectors.