Turbine Blade Trailing Edge Cooling Segmentation
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Solution Overview
Problem
The existing vane structures in turbomachine engines face challenges in efficiently cooling the trailing edge, particularly at the apex and base regions, where high temperatures and centrifugal stresses occur, leading to potential material degradation and reduced performance.
Innovation Solution
The vane design incorporates a series of through slots along the trailing edge, supplied by distinct air cavities and a downstream ramp, ensuring calibrated air distribution to optimize cooling, with independent air supply zones for the first, intermediate, and last slots, and additional cavities acting as heat screens to protect the central ducts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single cooling circuit is used for the trailing edge, then the structure is simple, but the cooling efficiency at the apex and base regions is insufficient
Solution Approach 1:
The cooling circuit is divided into three independent segments: a first circuit supplying the leading portion of the trailing edge, a second circuit supplying the intermediate portion, and a third circuit supplying the apex portion. Each circuit has its own air supply channel and cooling slots, allowing independent control of cooling air flow to different regions. This segmentation resolves the contradiction by enabling region-specific cooling optimization without requiring a single complex unified circuit.
Solution Approach 2:
Different regions of the trailing edge are provided with differentiated cooling characteristics: the leading portion receives cooling air through first slots supplied by a lower cavity, the intermediate portion receives cooling through intermediate slots supplied by a downstream ramp, and the apex portion receives cooling through last slots supplied by an upper cavity. This local quality approach allows each region to receive optimized cooling based on its specific thermal and mechanical conditions, improving overall cooling efficiency while maintaining structural clarity.
2Device complexity
If cooling air is supplied uniformly along the trailing edge, then the supply system is simple, but the cooling performance at high-stress regions (apex and base) is inadequate
Solution Approach 1:
The air supply system is segmented into three independent supply channels: a lower cavity supplying the first slots at the base region, a downstream ramp supplying intermediate slots at the middle region, and an upper cavity supplying the last slots at the apex region. This segmentation enables differentiated air supply strategies for different thermal zones, allowing increased cooling air flow to high-stress regions while maintaining a relatively simple overall supply architecture.
Solution Approach 2:
Each region of the trailing edge receives cooling air with locally optimized characteristics: the base region (first slots) receives cooling air from the lower cavity to handle centrifugal stresses, the intermediate region receives cooling from the downstream ramp, and the apex region (last slots) receives cooling from the upper cavity to handle high temperatures. This local quality approach ensures adequate temperature control at critical regions without requiring a uniformly complex supply system.
3Strength
If the trailing edge is designed to withstand high temperatures and centrifugal stresses, then material strength must be increased, but this increases device complexity and material requirements
Solution Approach 1:
Cooling air is supplied in advance to the trailing edge regions before they are subjected to extreme thermal and mechanical loads during operation. The three independent cooling circuits pre-cool the trailing edge, particularly the apex and base regions, preventing material degradation and maintaining strength without requiring excessive material thickness or complex structural reinforcements.
Solution Approach 2:
The high temperatures and centrifugal stresses that would normally be harmful to the trailing edge are converted into beneficial design drivers: the temperature distribution pattern caused by operational conditions is used to define the three-zone cooling strategy, with cooling air strategically directed to the most heavily stressed regions. This transforms the harmful thermal-mechanical environment into a basis for optimized cooling design, maintaining strength without excessive 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 enhances cooling efficiency at the trailing edge, particularly at the apex and base, reducing the risk of material stress and degradation, while maintaining optimal cooling in the intermediate region, thereby improving the vane's operational reliability and performance.
Implementation Method 1
Cooling is provided by circulating inside the vane fresh air drawn upstream of the combustion and taken in at the vane root, to travel along an inner circuit of the vane
Implementation Method 2
The cooling air circulating in the vane is discharged therefrom by drillings passing through its wall, which further enable an air film cooler than air from the combustion to be created at the outer surface of the vane in order, to limit the vane temperature
Implementation Method 3
The cooling air circulating in the vane is discharged therefrom by drillings passing through its wall, which further enable an air film cooler than air from the combustion to be created at the outer surface of the vane
Data Source
AI summary
A turbine blade including a root bearing an aerofoil extending in a direction of span and ending in a tip, this aerofoil including a leading edge and a trailing edge which are connected by a pressure face wall and a suction face wall, the trailing edge including on the pressure face side cooling slots. The trailing edge includes one or more first slots close to the root, which are supplied via a lower cavity; one or more last slots near the tip which are supplied via an upper cavity; intermediate slots situated between the first slots and the last slots supplied with air via a downstream line set; and wherein the lower cavities and upper cavities and the downstream line set are supplied distinctly at the level of the root.