Turbine Blade Tip Structure with Side Rails for Leakage Control
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Solution Overview
Problem
Gas turbine engines face reduced aerodynamic performance and high heat transfer due to flow leakage over the tips of airfoils, necessitating improved tip geometries that minimize over-tip loss while maintaining or improving tip heat transfer.
Innovation Solution
A tip structure for turbine blades featuring pressure and suction side rails that create shelf regions to control over-tip flow, reduce leakage, and enhance aerodynamic efficiency, while also incorporating cooling holes for heat management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If flow leakage over the tips of airfoils occurs, then the turbine blade operates with simple tip geometry, but aerodynamic performance is reduced and heat transfer increases
Solution Approach 1:
The tip structure is segmented into multiple functional components: pressure side rail, suction side rail, and shelf region. These segments work together to control flow leakage, with each rail positioned at specific locations (pressure side rail at 0.25-0.75 chord position, suction side rail at 0.50-0.75 chord position) to create distinct flow control zones that reduce energy loss while maintaining manufacturing feasibility
Solution Approach 2:
The invention adds a third dimension to the tip geometry by creating a shelf region that protrudes from the tip surface. This dimensional addition allows the rails to extend into the tip clearance space, effectively blocking leakage flow paths without increasing the planar footprint of the airfoil, thereby improving aerodynamic performance without proportionally increasing manufacturing complexity
2Ease of manufacture
If flow leakage over the tips of airfoils occurs, then the turbine blade operates with simple tip geometry, but heat transfer at the tip increases
Solution Approach 1:
The tip structure segments the heat transfer control function by positioning rails at specific chord positions (pressure side rail at 0.25-0.75, suction side rail at 0.50-0.75). This segmentation creates distinct flow control zones that redirect hot leakage flow away from the tip surface, reducing heat transfer to critical components while maintaining a manufacturable geometry
Solution Approach 2:
The shelf region acts as an intermediary structure between the pressure and suction side rails. It provides a physical barrier that intercepts hot leakage flow and redirects it along the shelf surface, preventing direct contact with the tip surface and surrounding components, thereby reducing heat transfer without requiring complex active cooling systems
Data Source
AI summary
A tip structure for a turbine blade comprises a tip surface of an airfoil that extends from a leading edge to a trailing edge and from a pressure side to a suction side of the airfoil. A suction side rail protrudes from the tip surface and comprises: a trailing portion extending flush with the suction side of the airfoil from an origination location at or near the trailing edge to an intermediate location on the suction side; and a leading portion extending from the intermediate location across the tip surface so as to create a suction side shelf region between the leading portion of the suction side rail and the suction side of the airfoil. A pressure side rail protrudes from the tip surface and comprises: a trailing segment extending flush with the pressure side of the airfoil from an origination location at or near the trailing edge to a middle location on the pressure side; and a leading segment extending from the middle location across a camber line on the tip surface so as to create a pressure side shelf region between the leading segment of the pressure side rail and the pressure side of the airfoil.