Gas Turbine Film Cooling Posts and Passageways
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Solution Overview
Problem
Existing film cooling methods for gas turbine engine components fail to effectively minimize the pre-discharged heating of cooling air, which limits the cooling efficiency of high-temperature components.
Innovation Solution
A cooled cast part design that incorporates a series of posts within the cooling plenum, where a first airflow cools the perimeter surface of these posts, thereby reducing the temperature of a second airflow that exits through outlets along the airfoil surface, providing enhanced film cooling by maintaining the airflow's coolness as it discharges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If film cooling air is discharged directly from cooling holes in the airfoil surface, then the cooling mechanism is simple, but the airflow undergoes pre-discharged heating which reduces cooling efficiency
Solution Approach 1:
The cooling system is segmented into two distinct airflow paths: a first airflow that travels through the airfoil core for direct cooling, and a second airflow that travels through a passageway adjacent to the core for film cooling. This segmentation allows each airflow to be cooled independently, preventing pre-discharge heating of the film cooling air while maintaining manufacturing simplicity through integrated casting.
Solution Approach 2:
The first airflow acts as an intermediary cooling medium that cools the perimeter surface of the passageway through which the second airflow travels. This intermediary cooling mechanism reduces the temperature of the film cooling air before it discharges, thereby improving cooling efficiency without complicating the overall system design.
2Temperature
If cooling passages are formed through the airfoil, then direct cooling is achieved, but the film cooling air is heated before discharge reducing effectiveness
Solution Approach 1:
The invention merges the direct cooling function and film cooling function into a single integrated airfoil structure. The cooling passages and plenum are formed as integral features of the airfoil body through investment casting, combining multiple cooling mechanisms without requiring separate components or complex assembly procedures.
Solution Approach 2:
The cooling architecture transitions from a single-dimensional passage through the airfoil to a two-dimensional configuration where the first airflow cools the perimeter surface of the passageway in which the second airflow travels. This dimensional expansion allows the film cooling air to be cooled by the first airflow without requiring additional external cooling systems.
3Reliability
If a first airflow cools the passageway through which the second airflow passes, then film cooling effectiveness is improved, but the device complexity increases
Solution Approach 1:
The cooling system is designed to be self-servicing where the first airflow, which is already present in the airfoil core for direct cooling purposes, simultaneously serves to cool the perimeter surface of the passageway. This self-service approach eliminates the need for additional external cooling systems or complex control mechanisms, improving film cooling effectiveness without proportionally increasing device complexity.
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 design effectively reduces the temperature of the airflow exiting the outlets, enhancing the film cooling effect and providing additional cooling near the leading edge of the airfoil, thus improving the overall cooling efficiency of gas turbine engine components.
Implementation Method 1
a first airflow cools the perimeter surface of these posts, thereby reducing the temperature of a second airflow that exits through outlets along the airfoil surface
Data Source
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AI summary
A cooled cast part (22) has an exterior surface. A cooling passageway system extends from at least one inlet port to a plurality of outlet ports (40, 42). The passageway system includes a first passageway (55) to at least a first (42) of the outlets and surrounding at least one post (66). The system includes a second passageway (62) to at least a second (40) of the outlets passing through the at least one post (66).