Parallel Corrugated Turbine Blade Surfaces for Wake Mixing
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Solution Overview
Problem
Turbomachine blades with finite trailing edge thickness create aerodynamic losses due to wake mixing, and existing enhanced wake mixing structures are limited by their applicability and manufacturing complexity.
Innovation Solution
The blade features parallel corrugated surfaces on both the outer and inner surfaces, combined with an impingement cooling structure, which are designed and manufactured using additive manufacturing to enhance wake mixing and reduce aerodynamic losses without increasing the complexity or cost of the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If wake mixing structures are added to reduce aerodynamic losses, then efficiency improves, but manufacturing complexity and cost increase
Solution Approach 1:
The patent applies corrugated surfaces with curved wave patterns on the airfoil trailing edge instead of traditional serrated or crenulated structures. This curvature enables more effective wake mixing while being manufacturable through modern fabrication techniques, resolving the contradiction between effectiveness and manufacturing complexity
Solution Approach 2:
The patent modifies the trailing edge geometry by introducing corrugated surfaces with specific wavelength and amplitude parameters. These parameter changes enhance wake mixing effectiveness while maintaining manufacturability, as the corrugated pattern can be produced through controlled manufacturing processes without excessive complexity
2Loss of energy
If corrugated surfaces are applied to enhance wake mixing, then aerodynamic performance improves, but manufacturing difficulty increases
Solution Approach 1:
The corrugated surfaces employ smooth curved wave patterns rather than sharp serrated edges, making them more amenable to manufacturing through modern techniques such as additive manufacturing, CNC machining, or composite layup, thereby improving ease of manufacture while maintaining wake mixing effectiveness
Solution Approach 2:
The patent specifies corrugated surface parameters (wavelength, amplitude, orientation) that balance aerodynamic performance with manufacturing feasibility. These parameter choices enable production through conventional or advanced manufacturing without excessive difficulty, resolving the contradiction between performance enhancement and manufacturing ease
3Productivity
If wake mixing structures are implemented, then efficiency improves, but the area of application is limited
Solution Approach 1:
The corrugated surface design serves multiple functions: enhancing wake mixing, providing structural reinforcement at the trailing edge, and potentially facilitating coolant flow in cooled blades. This multi-functionality expands the area of application across different blade types and turbomachine configurations, resolving the contradiction between efficiency improvement and adaptability
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 solution effectively minimizes velocity deficits and aerodynamic losses by promoting efficient wake mixing within turbomachine blades, improving efficiency without the need for complex air jets or increased space for mixing, thus enhancing power density and reducing costs.
Implementation Method 1
The relative flow velocity exiting, for example, a gas turbine airfoil is quite high, typically with Mach numbers of 0.5 or higher. The finite thickness of an airfoil trailing edge, however, creates a velocity deficit, i.e., a wake, which introduces losses in the flow through viscous mixing.
Implementation Method 2
an impingement cooling structure positioned within the radially extending chamber
Data Source
AI summary
A blade includes an airfoil body defined by a concave pressure side outer wall and a convex suction side outer wall that connect along leading and trailing edges and, therebetween, form a radially extending chamber for receiving the flow of a coolant. The airfoil body has an inner surface facing the radially extending chamber and an outer surface, a first corrugated surface on a portion of the outer surface, and a second corrugated surface on the inner surface paralleling the first corrugated surface. The corrugated surface on the outer surface of the airfoil provides wake mixing. The blade may also include an integrally formed impingement cooling structure having a third corrugated surface parallel to the second corrugated surface, which is made possible through additive manufacturing. The impingement cooling structure so formed provides improved cooling of the blade.