Airfoil Plenum Segmentation for Uniform Cooling Distribution
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Solution Overview
Problem
High temperatures in turbines lead to increased erosion, creep, and low cycle fatigue in airfoils and platforms, causing uneven cooling due to damage and streaming of cooling media in existing trench systems.
Innovation Solution
An airfoil design with a convex surface, a cavity, and a platform featuring a plenum with separate chambers and trenches, allowing for varied distribution of cooling media through staggered cooling passages to address temperature and erosion issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling media is released through trenches in airfoils and platforms, then film cooling is provided across surfaces, but erosion or damage to trenches causes streaming of cooling media resulting in uneven cooling
Solution Approach 1:
The plenum is divided into multiple separate chambers, each responsible for distributing cooling media to specific regions. This segmentation ensures that damage to one chamber does not affect the entire cooling system, maintaining reliability while achieving uniform cooling distribution across all surfaces.
Solution Approach 2:
Each plenum chamber is configured to deliver cooling media to specific locations based on local thermal requirements. The chambers can be independently controlled to provide varying cooling intensities to different regions, ensuring uniform overall cooling while adapting to local conditions and compensating for potential trench damage in specific areas.
2Productivity
If increased temperatures of compressed working fluid are used, then turbine performance and efficiency improve, but erosion, creep, and low cycle fatigue to airfoils and platforms increase
Solution Approach 1:
Cooling media is delivered through the plenum chambers to the airfoils and platforms before the hot working fluid causes significant thermal damage. This preliminary cooling action creates a protective thermal barrier that allows the turbine to operate at higher temperatures for improved efficiency while preventing excessive thermal stress and damage to the airfoils and platforms.
Solution Approach 2:
The cooling media acts as an intermediary between the hot working fluid and the airfoil/platform surfaces. By introducing this cooling intermediary through the plenum system, the patent enables the turbine to withstand higher working fluid temperatures without directly exposing the airfoils and platforms to extreme thermal conditions, thus improving efficiency while reducing thermal damage.
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
Enhances even cooling distribution across airfoil surfaces, reducing erosion, creep, and low cycle fatigue by varying cooling media pressure and flow rate to critical areas, thereby improving turbine performance and longevity.
Implementation Method 1
A cooling media released through the airfoils and/or platforms may provide film cooling across these surfaces
Implementation Method 2
an improved airfoil and method for cooling an airfoil platform that varies the distribution of the cooling media across the external surfaces of the airfoils and/or platforms
Data Source
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AI summary
An airfoil 40 includes an outer surface 42 having a leading edge 46, a trailing edge 48 downstream from the leading edge, and a convex surface 50 between the leading and trailing edges 46,48. A cavity 58 is inside the outer surface 42, and a platform 44 is connected to the outer surface 42 and defines a top surface 54 around at least a portion of the outer surface 42. A first plurality of trenches 80 is beneath the top surface 54 of the platform 44 upstream from the leading edge 46, wherein each trench 80 in the first plurality of trenches 80 is in fluid communication with the cavity 58 inside the outer surface 42. A first plurality of cooling passages 70 provide fluid communication from the first plurality of trenches 80 through the top surface 54 of the platform 44.