Gas Turbine Casing Surface Roughness Alignment for Lower Pressure Drop

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Solution Overview

Problem

Attritable gas turbine engines face efficiency reduction and increased size due to as-cast surface roughness in flow passages, leading to pressure drop challenges.

Innovation Solution

Utilizing additive manufacturing techniques, specifically build orientation control and Directed Energy Deposition, to align surface roughness with the flow direction, reducing pressure drop and enhancing performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If as-cast surfaces are used in flow passages, then manufacturing simplicity is maintained, but pressure drop increases and efficiency reduces

Engineering Contradiction:
Improvepressure dropVSAvoidsurface finishing complexity
Core Design Contradiction:
Loss of energyVSEase of manufacture

Solution Approach 1:

The surface roughness is controlled during the additive manufacturing process itself, before the component is put into service. By adjusting build orientation and process parameters during manufacturing, the optimal surface finish is achieved without requiring post-processing operations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the build orientation parameter and additive manufacturing process parameters to control the surface roughness characteristics. By varying these parameters, the surface roughness can be optimized to reduce pressure drop while maintaining manufacturing efficiency.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If surface roughness is reduced to improve flow efficiency, then pressure drop decreases, but manufacturing complexity increases

Engineering Contradiction:
Improveflow efficiencyVSAvoidmanufacturing process complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The additive manufacturing process serves multiple functions simultaneously: it creates the component geometry, controls the surface roughness, and optimizes the flow characteristics. This multi-functionality eliminates the need for separate surface finishing operations to reduce pressure drop.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent converts the typically harmful effect of surface roughness (increased pressure drop) into a beneficial feature by controlling its orientation and characteristics through build orientation. The surface roughness created by additive manufacturing is aligned to minimize flow resistance rather than maximize it.

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

3Loss of energy

If build orientation is controlled to align surface roughness with flow direction, then pressure drop is reduced, but manufacturing setup complexity increases

Engineering Contradiction:
Improvepressure dropVSAvoidbuild orientation control
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent introduces asymmetry in the build orientation to align the anisotropic surface roughness pattern with the flow direction. By deliberately orienting the build at specific angles, the surface features are configured to minimize flow resistance in the direction of fluid movement.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent addresses the surface roughness issue by adding the dimension of build orientation control. Instead of only modifying surface properties in the traditional sense, the solution lies in controlling the three-dimensional orientation of surface features relative to the flow path.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 process achieves reduced pressure drop and improved engine performance by controlling surface roughness orientation, thereby enhancing efficiency and potentially reducing engine size.

Implementation Method 1

Directed Energy Deposition (DED) additive manufacturing techniques enable utilization of 5 or 6 axis machines for controlled deposition direction along a desired path

Methodology Applied
Scientific EffectDirected Energy Deposition:

Data Source

PatentEP3670034B1Additively controlled surface roughness for designed performance
Publication Date: 2025.02.12 RTX CORP
  • EP3670034B1 patent drawingFigure 1
  • EP3670034B1 patent drawingFigure 2~5

AI summary

A process for additively controlled surface features of a gas turbine engine casing. The process comprises forming the casing having an inner surface and an outer surface opposite the inner surface; forming a surface feature on the casing proximate the inner surface, wherein the surface feature comprises a structure on the inner surface configured to align or misalign with respect to a flow direction of a working fluid in a flow path of the casing.