Gas Turbine Airfoil Cooling Passage Nested Configuration
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Solution Overview
Problem
Traditional serpentine cooling passages in gas turbine engine airfoils face inefficiencies, particularly in larger section widths, where larger channels do not maintain the same cooling mass flow efficiency as narrower channels, leading to significant cycle penalties and inadequate heat transfer.
Innovation Solution
The design incorporates a serpentine passageway with nested and overlapping portions on the suction and pressure sides, featuring at least three passes, including a third pass fluidly connected between the first and second passes, which are non-quadrilaterally shaped, such as triangularly shaped, to enhance heat transfer and structural rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If traditional serpentine cooling passages with larger channel sizes are used in airfoils with larger section widths, then the cooling passage can accommodate the larger airfoil size, but the cooling mass flow efficiency deteriorates compared to narrower channels
Solution Approach 1:
The cooling passage is divided into multiple nested passes (first pass, second pass, third pass) that are segmented into portions (first and second portions) arranged in series. This segmentation allows the cooling flow to traverse a longer effective path through the airfoil while maintaining efficient heat transfer characteristics, resolving the contradiction between accommodating larger airfoil volumes and maintaining cooling efficiency.
Solution Approach 2:
The cooling passage employs a nested configuration where the first pass, second pass, and third pass are arranged in a nested serpentine pattern. The passes are connected through turns that create a compact nested layout, allowing the cooling flow to efficiently traverse the entire airfoil section without requiring excessively large channel dimensions, thus maintaining cooling mass flow efficiency while adapting to larger airfoil volumes.
2Temperature
If cooling air is withdrawn from the compressor and used to cool turbine components, then the component temperature is reduced, but significant cycle penalties occur particularly in the low pressure turbine
Solution Approach 1:
The nested serpentine cooling passage configuration ensures continuous and efficient heat removal from the airfoil walls throughout the entire component structure. By providing a optimized flow path that maximizes heat transfer efficiency, the system achieves effective cooling with reduced cooling air flow requirements, thereby minimizing the cycle penalty associated with withdrawing cooling air from the compressor.
3Temperature
If internal features such as pedestals, impingement ribs, and trip strips are added to improve convective heat transfer, then the heat transfer coefficient increases, but the device complexity increases and these features are frequently inadequate without cooling holes and slots
Solution Approach 1:
The invention optimizes the geometric parameters of the cooling passage itself, including the nested serpentine configuration, pass arrangements, and turn designs, to maximize heat transfer efficiency. By carefully controlling passage dimensions, lengths, and configurations, the system achieves enhanced convective heat transfer without adding complex internal features such as pedestals, impingement ribs, or trip strips, thus reducing device complexity while maintaining effective cooling.
4Reliability
If cooling holes and slots are used to release cooling air into the gas path, then a film is created to protect the component, but the efficiency is lowered
Solution Approach 1:
The invention extracts and addresses the root cause of inefficiency by redesigning the internal cooling passage configuration itself rather than relying on external film cooling holes and slots. By optimizing the nested serpentine passage to provide adequate cooling through the airfoil structure, the need for additional film cooling features is reduced, thereby maintaining component protection while minimizing the efficiency loss associated with traditional film cooling approaches.
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
This configuration improves heat transfer efficiency and structural integrity by increasing the surface area to flow area ratio, allowing independent tuning of cooling flows and enhancing damage tolerance, while minimizing weight and pressure losses.
Implementation Method 1
This cooling air has a significantly lower temperature than the walls of the component, which allows for heat to be removed convectively from the walls into the air.
Implementation Method 2
This configuration improves heat transfer efficiency and structural integrity by increasing the surface area to flow area ratio
Data Source
Figure 1
Figure 2A~2B
Figure 3~4
AI summary
A component (64) for a gas turbine engine includes an exterior surface that provides pressure and suction sides (86,88). A cooling passage (90) in the component (64) includes a serpentine passageway (94) that has first and second passes (118,120) respectively configured to provide fluid flow in opposite directions from one another. The first pass (118) includes first and second portions (112,114) nested relative to one another and overlapping in a thickness direction. The first and second portions (112,114) are adjacent to one another by sharing a common wall (110). The first portion (112) is provided on the suction side (88). The second portion (114)is provided on the pressure side (86).