Ceramic Matrix Composite Airfoil Vane Baffle Cooling
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Solution Overview
Problem
Current baffle designs for gas turbine airfoil vanes in ceramic matrix composite materials lack effective cooling mechanisms, particularly at the trailing edge, leading to thermal gradients and potential hot spots due to inadequate airflow disruption and heat transfer.
Innovation Solution
A baffle design featuring a baffle wall with cooling holes and a tail that extends from the trailing end, which disrupts airflow by jetting or turbulating it, ensuring comprehensive cooling of the airfoil outer wall without direct contact, and optionally includes dimples or undulating shapes to enhance airflow disruption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple baffle design is used, then the device complexity is reduced, but the cooling performance deteriorates due to inadequate airflow disruption
Solution Approach 1:
The baffle incorporates cooling holes through its structure, transforming it from a solid barrier into a porous component that actively manages thermal fields by allowing cooling air to pass through and reach critical areas of the airfoil vane
Solution Approach 2:
The baffle includes a tail portion with curved or undulating geometry that extends into the cavity, creating turbulent flow patterns through its non-linear shape that enhances mixing and heat transfer efficiency
2Temperature
If cooling air flow is increased, then the heat transfer is improved, but the thermal gradients are not sufficiently reduced due to lack of airflow disruption
Solution Approach 1:
The curved tail portion of the baffle creates flow separation and turbulence when cooling air passes over it, disrupting laminar flow patterns and enhancing heat transfer to reduce thermal gradients in the airfoil vane
Solution Approach 2:
The baffle structure, particularly the tail portion, is designed to induce turbulent flow patterns that act similarly to vibration effects, enhancing convective heat transfer and reducing hot spots through chaotic flow behavior
3Reliability
If the baffle tail contacts the airfoil outer wall, then the cooling coverage is improved, but the risk of thermal contact and hot spot formation increases
Solution Approach 1:
The tail portion is designed to extend close to the airfoil outer wall surface without making direct contact, extracting the cooling function from direct contact and achieving thermal management through proximity-based convective cooling
Solution Approach 2:
The cooling air itself acts as an intermediary medium between the baffle tail and the airfoil outer wall, transferring heat through the fluid medium rather than through direct solid-to-solid thermal contact
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
The baffle design effectively reduces thermal gradients along the airfoil outer wall by improving heat transfer through enhanced airflow disruption, thereby preventing hot spots and ensuring efficient cooling of the ceramic matrix composite airfoil vanes.
Implementation Method 1
The baffle wall includes cooling holes that jet the cooling air toward the airfoil outer wall
Implementation Method 2
A baffle design featuring a baffle wall with cooling holes and a tail that extends from the trailing end, which disrupts airflow by jetting or turbulating it
Data Source
Figure 1
Figure 2~3
Figure 4~6C
AI summary
An airfoil vane (100) includes an airfoil section (106) including an outer wall (108) that defines an internal cavity (110); and a baffle (112; 212; 312; 412) situated in the internal cavity, the baffle including a baffle wall (113; 213; 313; 413) that defines a central cavity (114; 214; 314; 414) having a leading end (113a; 213;a 313a; 413a) and a trailing end (113b; 213b; 313b; 413b) corresponding to a leading end and a trailing end of the airfoil section, and a tail (118; 218; 318; 418) extending from the baffle wall, the tail including at least one feature configured to disturb an airflow surrounding the tail. A baffle for the airfoil vane assembly and a method of assembling a ceramic matrix composite airfoil vane are also disclosed.