Refractory Metal Core for Turbine Airfoil Cooling
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Solution Overview
Problem
Current cooling strategies for high-pressure turbine blades in gas turbine engines, operating at temperatures above 3100 degrees Fahrenheit, are inadequate due to increased operating temperatures, necessitating an improved cooling strategy for airfoil portions.
Innovation Solution
A refractory metal core is used to form serpentine cooling passageways in turbine airfoils, with multiple microcircuits and specific design features such as angled inlets and film holes to enhance heat transfer and prevent foreign matter entry, combined with a process involving investment casting and silica cores to create the airfoil portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional cooling strategies are used for high-pressure turbine blades, then the blades can operate at high temperatures, but the cooling effectiveness is insufficient due to increased operating temperatures above 3100°F
Solution Approach 1:
The cooling system is segmented into multiple independent microcircuits (first microcircuit, second microcircuit, third microcircuit) that distribute cooling fluid through separate serpentine pathways. This segmentation allows each circuit to independently cool specific regions of the airfoil, improving overall cooling effectiveness at high operating temperatures.
Solution Approach 2:
The cooling strategy transitions from simple internal cooling to a multi-dimensional approach by implementing serpentine pathways that traverse the airfoil thickness and multiple microcircuits distributed across different locations. This spatial distribution in multiple dimensions enhances heat transfer efficiency throughout the blade structure.
2Reliability
If serpentine cooling passages with multiple microcircuits are implemented, then cooling effectiveness increases, but the device complexity increases
Solution Approach 1:
Multiple cooling functions are merged into a single integrated refractory metal core structure that forms all serpentine cooling passages and microcircuits simultaneously. This consolidation achieves high cooling effectiveness through complex pathways while simplifying manufacturing by using one core instead of multiple separate components.
Solution Approach 2:
The refractory metal core serves multiple functions: it forms the serpentine cooling passages, creates the microcircuits, provides structural support during casting, and enables the complex cooling geometry. This multi-functionality reduces the number of separate components needed.
3Loss of energy
If cooling fluid flow is reduced by 40%, then energy efficiency improves, but maintaining cooling effectiveness at high temperatures becomes more difficult
Solution Approach 1:
The serpentine cooling passages utilize curved and winding pathways instead of straight lines, increasing the surface area contact between cooling fluid and blade material. This curved geometry enhances convective heat transfer efficiency, allowing effective cooling with reduced fluid flow rates.
Solution Approach 2:
The design replaces reliance on high volumetric cooling fluid flow with enhanced convective efficiency through optimized passage geometry. The serpentine configuration and microcircuit design create more effective heat transfer per unit of cooling fluid, substituting mechanical flow volume with thermal design optimization.
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 reduces cooling fluid flow by 40%, increases convective efficiency, and achieves high overall cooling effectiveness of 75%, providing improved thermal management for turbine engine components.
Implementation Method 1
cooling fluid flow... increases convective efficiency... improved thermal management
Implementation Method 2
a process for forming an airfoil portion of a turbine engine component involving investment casting and silica cores
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A turbine component has an airfoil portion (10) with at least one central core element (12), a pressure side wall (13), and a suction side wall (15). The airfoil portion (10) also has a serpentine cooling passageway (20;22) in at least one of the walls (13,15). In a preferred embodiment, the airfoil portion has a serpentine cooling passageway in both of the pressure and suction side walls (13,15). A refractory metal core (100) for forming the serpentine cooling passageway(s) is also described.