Airfoil Interior Micro-Bumps for Higher Cooling Heat Transfer
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Solution Overview
Problem
Current cooling enhancement techniques for gas turbine engine airfoils, such as small linear grooves and micro-depressions, are either inefficient in heat transfer or costly to implement, and existing pin-based designs obstruct cooling flow without significant heat transfer improvements on the exterior airfoil wall.
Innovation Solution
The airfoil features micro-bumps on its interior cooling surface that are discrete and noncontiguous, increasing turbulence and surface area, which enhances convective heat transfer, and can be formed using additive manufacturing processes or electrodischarge machining, allowing for efficient heat dissipation without the cost of traditional machining methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If small linear grooves are provided to increase surface area, then heat transfer surface area is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent applies curvature by using circular arc grooves instead of linear grooves. The curved geometry creates more effective turbulence and secondary flows that enhance heat transfer efficiency while maintaining manufacturability through standard machining processes.
Solution Approach 2:
The patent changes the geometric parameters of the grooves by specifying precise dimensions (depth of 0.02-0.08 inches, width of 0.015-0.06 inches, and radius of curvature of 0.01-0.04 inches) to optimize the balance between heat transfer enhancement and manufacturing feasibility.
2Temperature
If pins are provided to create turbulence, then heat transfer is improved, but cooling flow obstruction increases
Solution Approach 1:
The patent segments the cooling passage into multiple channels separated by partition walls, allowing turbulence-generating grooves to be placed strategically without completely blocking the flow path. This segmentation enables localized turbulence while maintaining overall flow continuity.
Solution Approach 2:
The grooves are designed with controlled depth (0.02-0.08 inches) that is sufficient to generate turbulence but limited to prevent excessive flow obstruction. The partial penetration into the passage wall creates the needed disturbance without completely blocking the cooling flow.
3Temperature
If micro-depressions are machined on airfoil core, then interior cooling surface geometry is improved, but manufacturing cost increases significantly
Solution Approach 1:
Instead of machining complex micro-depressions into the airfoil core (which is costly), the patent inverts the approach by providing corresponding protrusions on the core that create the desired micro-bump features on the interior cooling surface during casting. This inversion transforms a costly post-processing operation into an integrated molding feature.
Solution Approach 2:
The cooling enhancement features are built into the core geometry before casting, so the micro-bump pattern is automatically formed on the interior cooling surface during the casting process itself, eliminating the need for subsequent expensive machining operations.
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 micro-bump design significantly improves convective heat transfer by increasing turbulence and surface area, effectively managing heat dissipation in gas turbine engine airfoils while being cost-effective and adaptable to complex geometries.
Implementation Method 1
The micro-bumps discrete from one another in multiple directions along the interior cooling surface and noncontiguous from one another about 360° of each micro-bump along the interior cooling surface
Implementation Method 2
enhances convective heat transfer
Data Source
Figure 1
Figure 2A~5
Figure 3A~6
AI summary
An airfoil includes a body that includes leading and trailing edges joined by spaced apart pressure and suction sides to provide an exterior airfoil surface. A cooling passage is arranged interiorly of the exterior airfoil surface and provides an interior surface. The interior cooling surface includes micro-bumps that protrude from the interior cooling surface into the cooling passage. The micro-bumps are discrete from and noncontiguous relative to one another in multiple directions along the interior cooling surface. The micro-bumps may be provided while forming the airfoil or using correspondingly shaped micro-depressions on an airfoil core.