Gas Turbine Casing Surface Roughness for Lower Flow Pressure Drop
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Solution Overview
Problem
Attritable gas turbine engines face efficiency reductions due to as-cast surface roughness in flow passages, leading to pressure drop challenges and increased component size, necessitating a cost-effective solution to improve flow efficiency and reduce engine size.
Innovation Solution
The process involves using additive manufacturing to create controlled surface features, such as scallop-shaped formations or other geometries, aligned or misaligned with the flow direction within the engine's internal flow passages to reduce fluid resistance, leveraging directed energy deposition and model-based techniques to optimize surface roughness and fluid flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional manufacturing techniques are used for attritable engines, then durability and safety requirements are met, but manufacturing cost and complexity increase
Solution Approach 1:
The patent changes the surface roughness parameters by controlling additive manufacturing process parameters (laser power, scan speed, hatch spacing) to create specific surface profiles that reduce pressure drop while maintaining structural integrity for attritable engine applications
Solution Approach 2:
The patent applies additive manufacturing for attritable (expendable) engines that have limited lifespan, using cost-effective manufacturing approaches suitable for single-use or limited-use propulsion systems where full durability requirements are not needed
2Ease of manufacture
If as-cast surfaces are used in flow path components, then manufacturing is simple, but pressure drop increases and efficiency reduces
Solution Approach 1:
The patent applies local quality by creating specific surface features (ridges, valleys, dimples) at localized regions within the flow passage rather than uniform surface treatment, optimizing flow characteristics in critical areas while maintaining manufacturing simplicity
Solution Approach 2:
The patent uses curved surface features including scallop-shaped formations with rounded edges and continuous curved profiles that reduce flow separation and turbulence compared to sharp-edged geometric features
3Loss of energy
If surface roughness is reduced to improve flow efficiency, then pressure drop decreases, but component size must increase to maintain flow capacity
Solution Approach 1:
The patent optimizes surface feature parameters (height, width, spacing, profile shape) to achieve the minimum effective roughness that reduces pressure drop without requiring increased component dimensions, using controlled additive manufacturing to create optimal surface profiles
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
This approach reduces pressure drop and enhances engine performance by aligning surface roughness with the flow direction, allowing for more efficient fluid flow and potentially smaller engine designs, while also lowering production costs and complexity.
Implementation Method 1
additive manufacturing techniques may be deployed in substitute to reduce cost and complexity
Implementation Method 2
leveraging directed energy deposition and model-based techniques to optimize surface roughness and fluid flow
Data Source
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.