High-Pressure Turbine Double Baffle Sealing for Gas Leakage Control

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Solution Overview

Problem

Conventional turbomachines suffer from reduced efficiency due to gas leakage and disruption in the annular path caused by bleed air collection from compressors, which also reduces the performance of the turbomachine.

Innovation Solution

A high-pressure gas turbine design featuring a double baffle system with upstream and downstream sealing elements and an upstream annular cavity to minimize gas leakage and reduce the need for bleed air, utilizing deflectors and a cavity to create pressure losses and redirect gases effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If a single baffle system is used to prevent gas leakage between the nozzle guide vane assembly and movable wheel, then gas leakage is partially reduced, but the leakage flow rate remains insufficiently controlled and bleed air requirements remain high

Engineering Contradiction:

Improvegas leakageVSAvoidbleed air requirements

Core Design Contradiction:

Loss of substanceVSLoss of energy

Solution Approach 1:

The single baffle is divided into a double baffle system with an upstream baffle and a downstream baffle positioned at different axial locations. This segmentation creates multiple barriers to gas leakage, allowing each baffle to address specific leakage paths while working together to achieve superior sealing performance that reduces both gas leakage and bleed air requirements.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The deflectors are extended in the radial direction to create radially external portions that protrude into the annular path. This dimensional extension creates additional flow resistance and redirects leakage gases back into the annular path, adding a radial dimension to the sealing mechanism that enhances the effectiveness of the axial baffles.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Loss of substance

If bleed air is collected from compressors to redirect leakage gases, then gas leakage is controlled, but the efficiency of the turbomachine is reduced

Engineering Contradiction:

Improvegas leakage controlVSAvoidturbomachine efficiency

Core Design Contradiction:

Loss of substanceVSProductivity

Solution Approach 1:

The double baffle system with deflectors creates a self-regulating sealing mechanism that uses the pressure differential and flow dynamics of the gas itself to redirect leakage back into the annular path. The radially external portions of the deflectors act as flow guides that passively redirect gases without requiring external bleed air intervention, allowing the system to control its own leakage internally.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system converts the harmful leakage gas flow into a beneficial flow by using the deflectors to redirect the leakage gases back into the annular path where they can be productively used. The double baffle configuration creates pressure losses that favorably redirect the gases, transforming what was previously waste leakage into useful flow that contributes to turbomachine performance.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Loss of substance

If the baffle extends radially internally to the internal annular platform, then gas leakage is reduced, but the structural complexity and manufacturing difficulty increase

Engineering Contradiction:

Improvegas leakageVSAvoidbaffle structure complexity

Core Design Contradiction:

Loss of substanceVSEase of manufacture

Solution Approach 1:

The baffle is segmented into distinct axial portions (upstream and downstream) with the deflector forming a separate radial extension. This segmentation allows each portion to be optimized independently for its specific function while simplifying the overall manufacturing process compared to a monolithic complex structure extending fully radially internally.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The deflector is configured with different geometries at different locations: the upstream portion has specific curvature to redirect gases, while the radially external portion has extended reach into the annular path. This local differentiation of geometry optimizes the sealing performance at each location without requiring the entire baffle structure to be complex, simplifying manufacturing while maintaining effectiveness.

Inventive Principle:

Principle #3Local quality

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 double baffle system reduces gas leakage and bleed air requirements, enhancing turbomachine efficiency and reducing specific fuel consumption.

Implementation Method 1

The double baffle generates a pressure loss which reduces the flow rate of the gas leaking radially inwards from the annular path

Methodology Applied

Scientific EffectPressure loss: Pressure Drop

Implementation Method 2

the upstream annular cavity also makes it possible to reduce such a leakage flow rate, by creating additional pressure loss

Methodology Applied

Scientific EffectPressure loss: Pressure Drop

Data Source

PatentUS12492644B2High-pressure gas turbine for turbomachine and turbomachine

Publication Date: 2025.12.09 SAFRAN AIRCRAFT ENGINES SAS

AI summary

A high-pressure gas turbine for a turbomachine includes a nozzle guide vane assembly, an annular array of movable blades mounted downstream of the nozzle guide vane assembly, a bleed cavity, an upstream sealing element mounted on the nozzle guide vane assembly and a downstream sealing element mounted on the annular array of movable blades, a double baffle being formed by said upstream and downstream sealing elements, an external upstream cavity being formed in the upstream sealing element.