Effusion Cooling Apertures with Segmented Metering and Diffusing Portions
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing gas turbine engine components, such as turbine blades and combustion chamber walls, face inefficiencies in cooling due to high velocity coolant jets detaching from surfaces and non-uniform coolant distribution, leading to reduced cooling effectiveness and potential hot spots.
Innovation Solution
The design incorporates effusion cooling apertures with a metering portion and a diffusing portion arranged in series, featuring a diagonal inlet and a quadrilateral outlet shape, which reduces coolant exit velocity and enhances film coverage by aerodynamically blending the flow, thereby improving heat transfer and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If cylindrical effusion cooling apertures are used, then the structure is simple and manufacturing is easy, but the coolant jets detach from the surface and cooling effectiveness is reduced
Solution Approach 1:
The effusion cooling aperture is divided into multiple segments: an inlet portion, a metering portion, and a diffusing portion. This segmentation allows each portion to perform its specific function - the metering portion controls coolant flow rate while the diffusing portion reduces jet velocity and improves surface attachment, thereby resolving the contradiction between manufacturing simplicity and cooling effectiveness.
Solution Approach 2:
The aperture geometry parameters are changed from a simple cylindrical shape to a complex multi-portions shape with varying cross-sectional areas. The metering portion has a smaller cross-section to control flow, while the diffusing portion has an expanding cross-section to reduce velocity. These parameter changes improve cooling effectiveness while maintaining manufacturability through standardized design.
2Reliability
If the number of effusion cooling apertures is increased to improve coolant distribution, then cooling uniformity improves, but manufacturing complexity and cost increase
Solution Approach 1:
Each effusion cooling aperture is segmented into functional portions that work together to achieve uniform coolant distribution. The metering portion ensures consistent flow rate control, while the diffusing portion creates a broader, more uniform coolant spread on the surface, reducing the need for a higher number of apertures and thereby managing device complexity.
Solution Approach 2:
The aperture design incorporates local quality variations through the metering and diffusing portions, where the cross-sectional area changes along the flow path. This local geometric variation optimizes coolant distribution characteristics at each location within the aperture, achieving improved cooling uniformity without proportionally increasing overall device complexity.
3Temperature
If effusion cooling apertures are angled in the direction of flow, then heat transfer from wall to coolant increases, but coolant jet velocity perpendicular to surface increases causing detachment
Solution Approach 1:
The effusion cooling aperture is segmented into an inlet portion, metering portion, and diffusing portion. The diffusing portion specifically addresses the velocity issue by expanding the cross-sectional area to reduce coolant jet velocity perpendicular to the surface, preventing detachment and improving film stability while the angled configuration maintains effective heat transfer.
Solution Approach 2:
The aperture geometry parameters are changed to include an expanding cross-section in the diffusing portion. This parameter change reduces the velocity of coolant exiting the aperture while maintaining the angled configuration for effective heat transfer, thereby resolving the contradiction between heat transfer rate and coolant film stability.
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 achieves improved coolant film quality and temperature reduction, enhancing the cooling effectiveness of gas turbine engine components by up to 100°C compared to conventional methods, while allowing for the use of less expensive superalloys or operating high-temperature resistant alloys at higher temperatures.
Implementation Method 1
the increased internal surface area increases the heat transfer from the wall of the component to the coolant
Implementation Method 2
The effusion cooling apertures are arranged at an angle to the second surface... providing a film of coolant on the outer surface
Data Source
AI summary
A cooled gas turbine engine component comprises a wall which has a plurality of effusion cooling apertures extending there-through from a first surface to a second surface. The apertures are arranged at an angle to the second surface and each aperture has an inlet in the first surface and an outlet in the second surface. Each aperture has a metering portion and a diffusing portion arranged in flow series and each metering portion is elongate and the width is greater than the length of the metering portion. Each diffusing portion increases in dimension in the length from the metering portion to the outlet. Each outlet has a rectangular shape in the second surface of the wall. Each inlet has an elongate shape in the first surface of the wall and the inlet in the wall is arranged substantially diagonally with respect to the outlet in the wall.