Laser Shock Raised Elements for Turbomachine Blade Boundary Layer Control
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Solution Overview
Problem
Existing methods for improving the aerodynamic efficiency of turbomachine blades and enhancing their resistance to mechanical and thermal stresses through laser shock treatment create undesirable surface disruptions, which hinder the goal of maintaining a smooth surface for optimal performance.
Innovation Solution
The method involves applying laser shocks to create raised elements on the surface, turning the disruptive effects into advantages by promoting specific boundary layer disruptions to control turbulence and improve fluid flow behavior, allowing for customizable impact shapes, energies, and geometries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If laser shock impacts are applied to compress underlying layers on the blade surface to improve resistance to fatigue and mechanical stresses, then the mechanical strength and fatigue resistance are improved, but surface disruptions and roughness are created that deteriorate aerodynamic efficiency
Solution Approach 1:
The invention converts the harmful surface disruptions created by laser shock impacts into beneficial turbulence-controlling elements. By deliberately designing raised elements with specific geometries (height, spacing, distribution) that trip the boundary layer at controlled locations, the surface roughness that would normally degrade aerodynamic performance is transformed into a tool for active flow control, delaying separation and improving overall blade efficiency
Solution Approach 2:
The invention applies different surface treatments to different locations on the blade surface. Raised elements are strategically placed in specific zones (such as near the leading edge or in separation-prone regions) where boundary layer control is most beneficial, while other areas maintain smooth surfaces for optimal aerodynamic flow. This localized approach allows simultaneous optimization of both mechanical strength (where impacts are applied) and aerodynamic efficiency (where smooth surfaces or controlled roughness are present)
2Manufacturing precision
If polishing of the blade surface is performed to improve aerodynamic efficiency, then the aerodynamic performance is improved, but the resistance to fatigue and mechanical stresses is reduced
Solution Approach 1:
The invention merges two previously separate surface treatment processes into a single integrated approach: laser shock impacts are applied to create both the desired compressive stress field in the underlying material (improving fatigue resistance) and the raised surface elements (controlling boundary layer turbulence). This combination eliminates the need to choose between polishing for aerodynamics or impacting for strength, as both functions are achieved simultaneously through the impact process itself
3Manufacturing precision
If adhesive films of the Mylar type are applied to produce the shark skin effect to improve aerodynamic efficiency, then the specific fuel consumption is reduced, but the mechanical and thermal properties of the blade surface are not improved
Solution Approach 1:
The invention makes the laser shock impact process multi-functional. Instead of being limited to solely improving mechanical properties, the same impact process simultaneously creates raised surface elements that control boundary layer transitions and delay separation. This single process achieves both mechanical strengthening (through compressive residual stresses) and aerodynamic optimization (through controlled surface roughness), eliminating the need for separate adhesive film applications
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 enhances the mechanical and thermal properties of turbomachine blades by controlling the transition between laminar and turbulent boundary layers, reducing separation, and optimizing fluid flow, leading to improved efficiency and stress resistance.
Implementation Method 1
The method comprises covering the surfaces to be treated with an ablative coating such as a paint or an adhesive strip and the firing of a laser beam in the direction of the surface thus coated in order to produce the ablation of the covering material by spraying
Implementation Method 2
Shock waves are generated that are the source of the compression of the treated material
Implementation Method 3
the compression of underlying layers on their surface, in particular in the zones close to the leading edge
Implementation Method 4
produce raised elements on the wall surface capable of being swept by a fluid in order to control the intensity of turbulence in a transition zone
Implementation Method 5
control the intensity of turbulence in a transition zone
Data Source
AI summary
A method for producing, on the surface of a wall capable of being swept by a fluid, raised elements forming disruptions of the boundary layer is disclosed. The method includes applying laser shocks to the surface so as to create peaks on the edge of the impact zones such that the peaks form the disruptive raised elements.