Turbine Blade Microcircuits for Cooling Effectiveness
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Solution Overview
Problem
Current turbine engine cooling technologies face challenges in achieving high cooling effectiveness and convective efficiency, leading to increased coolant flow requirements when gas temperatures rise, which is difficult to manage for efficiency improvements.
Innovation Solution
The implementation of a turbine engine component with integrated serpentine cooling microcircuits on both the suction and pressure sides of the airfoil portion, along with a thermal barrier coating, to enhance film cooling, heat pick-up, and heat transfer coefficients, allowing for reduced coolant flow by optimizing the cooling design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional cooling channels with trip strips are used, then cooling flow can be increased, but cooling effectiveness and convective efficiency remain limited (around 0.50 and 0.40 respectively)
Solution Approach 1:
The cooling system is segmented into multiple independent microcircuits (first cooling microcircuit in suction side, second cooling microcircuit in pressure side, and integrated platform cooling microcircuit) that can operate simultaneously. Each microcircuit has its own cooling passages and exits, allowing distributed cooling across different blade regions, which improves overall cooling effectiveness without requiring excessive coolant flow.
Solution Approach 2:
The invention transitions from conventional 2D cooling channel cross-sections to 3D integrated microcircuits that wrap around the blade platform and extend into the tip region. The cooling passages are configured in serpentine patterns with multiple levels and orientations, utilizing three-dimensional space to maximize heat transfer surface area and improve convective efficiency.
2Temperature
If gas temperature increases from 2500°F to 2850°F, then turbine efficiency improves, but cooling flow must increase by more than 5% of engine core flow
Solution Approach 1:
Cooling is applied preliminarily and continuously throughout the blade structure before the metal reaches critical temperatures. The microcircuits are pre-configured with thermal barrier coatings and optimized passage geometries that establish effective heat transfer from the outset, preventing temperature buildup rather than reacting to it. This allows the system to handle higher gas temperatures without proportionally increasing coolant flow.
Solution Approach 2:
The invention changes key cooling parameters including: (1) increasing heat transfer coefficients through optimized passage geometry and trip strip configuration, (2) improving film cooling effectiveness through strategically placed exits on both suction and pressure sides, (3) enhancing thermal barrier coating properties, and (4) optimizing the distribution of coolant flow across multiple microcircuits. These parameter changes enable higher gas temperatures to be sustained with reduced coolant flow requirements.
3Temperature
If more cooling flow is used to maintain effectiveness, then metal temperature can be controlled, but turbine efficiency decreases due to parasitic loss
Solution Approach 1:
The cooling microcircuits are designed to utilize the blade's own structure and flow paths for cooling. The serpentine passages follow the contour of the airfoil, using the blade geometry itself as part of the cooling system. The integrated platform cooling utilizes the platform structure, and tip cooling utilizes the tip region, allowing the blade to cool itself efficiently without requiring external cooling systems or excessive coolant flow.
Solution Approach 2:
The invention replaces conventional mechanical cooling systems with thermally optimized microcircuits that rely on enhanced natural convection and conduction through carefully designed passage geometries. The trip strips create controlled turbulence that enhances heat transfer without requiring additional mechanical cooling components. This substitution reduces the mechanical complexity and coolant flow requirements while maintaining effective metal temperature control.
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 approach improves cooling effectiveness to 0.8 and convective efficiency to 0.5, reducing coolant flow to no more than 3.5% of the engine core flow, effectively managing increased gas temperatures without increasing cooling flow.
Implementation Method 1
cooling flow passes through these blades by means of internal cooling channels 14 that are turbulated with trip strips 16 for enhancing heat transfer inside the blade
Implementation Method 2
coating the airfoil with a thermal barrier coating is a first requirement
Implementation Method 3
improved heat transfer coefficients in the blade cooling passages
Data Source
AI summary
A turbine engine component has an airfoil portion with a pressure side and a suction side. The turbine engine component further has a first cooling microcircuit for cooling the suction side of the airfoil portion. The first cooling microcircuit is embedded within a first wall forming the suction side. The first cooling microcircuit has a circuit for allowing a cooling fluid in the first cooling microcircuit to exit at a tip of the airfoil portion. The turbine engine component also has a second cooling microcircuit embedded within a second wall forming the pressure side of the airfoil portion.