Turbomachine Blade Cooling Circuit Segmentation
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Solution Overview
Problem
The cooling of high-pressure turbine blades in turbojet engines requires continuous improvement due to evolving operating conditions and performance requirements, with existing designs not adequately addressing the need for efficient cooling while minimizing fuel consumption and extending blade life.
Innovation Solution
A turbine blade design featuring a central duct that supplies air to a cavity under the bath, forming an L-shaped duct with the intrados wall, and a serpentine median circuit with radial ducts that minimize air flow heating, allowing for effective cooling of critical areas like the trailing edge and leading edge, while maintaining a high flow rate in the upstream and downstream circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a traditional cooling circuit is used in turbine blades, then cooling coverage is provided, but air flow rate is high causing increased fuel consumption
Solution Approach 1:
The cooling circuit is divided into multiple independent circuits (first circuit with first radial duct, second circuit with second radial duct, third circuit with third radial duct) that can be independently controlled. This segmentation allows optimization of air flow distribution to reduce total cooling air requirement while maintaining effective cooling coverage across different blade regions.
Solution Approach 2:
Different cooling circuits are designed with different characteristics suited to specific blade regions. The first radial duct serves the leading edge, the second radial duct serves the middle portion, and the third radial duct serves the trailing edge. Each circuit can be optimized for its specific thermal requirements, improving overall cooling efficiency and reducing total air consumption.
2Reliability
If cooling air is supplied to all regions of the blade, then comprehensive cooling is achieved, but the complexity of the cooling circuit increases
Solution Approach 1:
The blade cooling system is segmented into three independent radial ducts (first, second, and third radial ducts) that can be independently controlled. This segmentation allows for simplified design of each individual duct while achieving comprehensive cooling coverage when all ducts operate together, reducing the complexity of any single duct path.
Solution Approach 2:
Each radial duct serves multiple functions: cooling the specific blade region it serves, and potentially serving as a thermal barrier for adjacent hot zones. The cooling circuits are designed to work independently yet complementarily, providing universal cooling coverage across the entire blade while maintaining relatively simple individual circuit designs.
3Power
If the blade operates at higher temperatures for improved efficiency, then power output increases, but blade life decreases due to thermal stress
Solution Approach 1:
Different regions of the blade are cooled according to their specific thermal requirements and stress conditions. The leading edge, middle portion, and trailing edge each have dedicated cooling circuits that can be independently optimized. This allows the blade to operate at higher overall temperatures for improved power output while maintaining lower local temperatures in critical regions to extend blade life.
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 reduces the air flow necessary for cooling the blade's middle portion, effectively cooling critical areas with minimal heating, thereby reducing fuel consumption and extending blade life by optimizing heat exchange and air distribution within the blade's internal circuits.
Implementation Method 1
The cooling of the turbine blades is ensured by circulating in each blade air taken from upstream of the combustion chamber... this air being evacuated by holes and/or slots passing through the walls of these blades
Implementation Method 2
circulating in each blade air taken from upstream of the combustion chamber and admitted at the root of the blade, this air being evacuated by holes and/or slots passing through the walls of these blades
Data Source
Figure 1~3
Figure 4~7
Figure 8~10
AI summary
The invention concerns a turbine blade (11) comprising a root (P) carrying an impeller (12) terminated by a tip (S) in the form of a squealer tip (B). This impeller (12) also comprises a serpentine median circuit (28), including a first radial pipe (41) collecting air at the root and that is connected by a first bend (46) to a second radial pipe (42) that is connected by a second bend (47) to a third radial pipe (43), a cavity (36) under the squealer tip running along the pressure side wall (19), extending from a central region of the tip (S) to the trailing edge (17), and a radial central pipe (34) collecting air at the root extending between at least two of the three pipes (41, 42, 43) of the median circuit (28) and directly supplying the cavity (36) under the squealer tip.