Blunt Tip Turbine Blade Cooling via Pressure Side Flute
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Turbine blade tips in gas turbine engines are challenging to cool effectively due to exposure to hot combustion gases and occasional tip rubbing with the shroud, leading to oxidation, wear, and reduced efficiency.
Innovation Solution
A turbine blade design featuring a blunt tip cap without squealer ribs, with an internal cooling circuit and a pressure side flute that extends below the tip cap to enhance cooling and sealing, while maintaining structural integrity and aerodynamic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If squealer ribs are added to the blade tip to handle tip rubs, then reliability against tip rubbing is improved, but cooling effectiveness deteriorates due to increased exposure to hot combustion gases
Solution Approach 1:
The invention removes the squealer ribs from the blade tip design, extracting the harmful structural element that worsened cooling effectiveness. The blunt tip cavity design eliminates the ribs that created additional hot gas exposure surfaces, thereby resolving the contradiction between tip rub resistance and cooling effectiveness.
Solution Approach 2:
The invention uses a thin film of cooling air discharged from the tip shelf and flute to protect the blade tip. This cooling air film acts as a flexible thermal barrier that shields the tip cavity and blunt tip from hot combustion gases, maintaining cooling effectiveness while preserving tip rub handling capability.
2Temperature
If tip shelf and cooling structures are added to protect against hot gases, then cooling effectiveness is improved, but device complexity increases
Solution Approach 1:
The invention merges the tip shelf and flute cooling structures into a unified blunt tip cavity design. The tip shelf extends from the pressure side and the flute extends from the suction side, both feeding into the same tip cavity space. This integration reduces overall structural complexity compared to having separate, independent cooling systems for each side.
Solution Approach 2:
The tip cavity serves multiple functions: it receives cooling air from both the tip shelf and flute, provides a sealed chamber for cooling air accumulation, and protects the blunt tip from hot gases. This multi-functionality reduces the need for additional separate cooling components, thereby managing device complexity while maintaining cooling effectiveness.
3Temperature
If cooling air flow is increased to protect the tip, then cooling effectiveness is improved, but energy loss increases due to bled compressor air
Solution Approach 1:
The invention applies cooling air locally at the tip region where it is most needed, rather than cooling the entire blade uniformly. The tip shelf and flute structures direct cooling air specifically to the tip cavity and blunt tip area, concentrating the cooling effect where heat exposure is highest. This localized approach reduces the total amount of cooling air required from compressor bleed.
Solution Approach 2:
The invention uses a controlled amount of cooling air that is sufficient to protect the tip region without excessive air bleed. The tip shelf and flute structures efficiently utilize the cooling air by directing it precisely to the hot gas exposure zones, achieving adequate protection with partial action rather than requiring excessive cooling air flow throughout the entire blade.
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 design improves tip cooling, reduces oxidation and wear, and maintains efficiency by creating a thermally insulating air layer and enhancing sealing performance, thus extending the blade's useful life and maintaining turbine efficiency.
Implementation Method 1
hollow airfoils with internal cooling circuits therein which use air bled from the compressor for cooling thereof during operation
Implementation Method 2
internal cooling circuits therein which use air bled from the compressor for cooling thereof during operation
Implementation Method 3
enhancing tip cooling by shielding the tip with a cooling air film for protection against the radial migration of combustion gases over the tip
Data Source
AI summary
A turbine airfoil includes opposite pressure and suction sidewalls, and extends in chord between opposite leading and trailing edges and in span from a root to an outer tip cap. The tip cap bridges the sidewalls, and a flute extends chordally along the pressure sidewall and below the tip cap.