Gas Turbine Vane Cluster EDM Cooling for Obstructed Leading Edges
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Solution Overview
Problem
Conventional cooling systems for gas turbine engine vane clusters face challenges in effectively cooling the leading edges of vanes due to obstructed regions between vanes, leading to insufficient cooling and manufacturing difficulties with existing techniques like laser machining.
Innovation Solution
The implementation of Electrical Discharge Machining (EDM) cooling holes in visually obstructed regions, specifically shaped EDM cooling holes that connect to the leading edge core, providing increased coolant flow and improved film cooling through a diffuser design, which facilitates better adhesion of cooling air to the vane surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cooling systems are used for vane clusters, then the system structure is simple and manufacturing is easier, but the cooling effectiveness in obstructed regions between vanes is insufficient
Solution Approach 1:
The cooling system is segmented into multiple independent cooling holes distributed across the vane cluster, with specific holes positioned in obstructed regions. Each cooling hole operates independently to deliver coolant to specific areas, allowing complex cooling patterns to be achieved through multiple simple components rather than a single complex cooling structure.
Solution Approach 2:
Different regions of the vane cluster are provided with different cooling configurations. Obstructed regions between vanes receive specialized cooling holes positioned to target these specific areas, while other regions have different cooling hole arrangements. This localized approach ensures optimal cooling effectiveness in each region without requiring complex manufacturing throughout the entire structure.
2Reliability
If cooling holes are positioned in visually obstructed regions to improve cooling, then cooling effectiveness increases, but manufacturing precision requirements increase
Solution Approach 1:
Traditional mechanical drilling or laser machining methods are replaced with Electrical Discharge Machining (EDM) for creating cooling holes in obstructed regions. EDM uses electrical discharges to erode material precisely, eliminating the need for complex mechanical tool access and achieving high positioning precision in visually obstructed regions where conventional mechanical methods would be difficult or impossible to implement.
Solution Approach 2:
The manufacturing method transitions from mechanical removal processes to electrical discharge processes, fundamentally changing the physical parameter used for material removal. This parameter change enables precise hole placement in obstructed regions by using electrical field distribution rather than mechanical tool paths, thereby achieving high positioning precision without the constraints of mechanical accessibility.
3Reliability
If coolant flow is increased to improve cooling, then cooling effectiveness improves, but film cooling adhesion to the vane surface decreases
Solution Approach 1:
Different cooling holes are designed with different characteristics suited to their specific locations and functions. Some holes are optimized for high flow rate to deliver sufficient coolant volume, while others are designed with specific geometries to enhance film adhesion in critical regions. This localized optimization allows the system to achieve both high overall cooling effectiveness and maintained film adhesion without requiring uniform high flow throughout all holes.
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
Enhances cooling efficiency by directing coolant closer to the leading edge and improving film cooling effectiveness, addressing the limitations of conventional systems by increasing coolant flow and adhesion to the vane surface.
Implementation Method 1
The implementation of Electrical Discharge Machining (EDM) cooling holes in visually obstructed regions
Implementation Method 2
improving film cooling effectiveness, addressing the limitations of conventional systems by increasing coolant flow and adhesion to the vane surface
Data Source
Figure 1
Figure 2~4
AI summary
A vane cluster (100) for a gas turbine engine (20) includes an outer diameter platform (110) and an inner diameter platform (120). A plurality of vanes (130) span from the outer diameter platform (110) to the inner diameter platform (120). At least one inbound region (102) is defined between a first vane (130) of the plurality of vanes (130) and a second vane (130) of the plurality of vanes (130). The first vane (130) includes a suction side facing the inbound region (102). Each of the vanes (130) includes a leading edge core passage and a trailing edge core passage. A plurality of electrical discharge machined (EDM) holes (140) are disposed within at least 12.7mm of a leading edge (104) of the first vane (130). Each of the EDM holes (140) connect the leading edge core passage of the vane (130) to an exterior surface of the vane (130).