Turbine Platform Cooling Hole Pattern for Temperature Uniformity
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Solution Overview
Problem
Turbine blades in gas turbine engines face localized hot spots due to inadequate cooling, leading to reduced lifespan and potential damage, as conventional cooling systems struggle to maintain uniform temperatures across the blade, particularly under high centrifugal forces and airflow conditions.
Innovation Solution
A cooling system utilizing a combination of external film cooling and internal convection, where a cooling medium flows through strategically positioned cooling openings on the platform, forming a film layer on the outer surface and convective cooling internally, to reduce temperature gradients and allow for more consistent cooling across the turbine blade.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional cooling systems with internal cooling channels are used, then the turbine blade can withstand high temperatures, but localized hot spots form due to inadequate cooling under centrifugal forces and airflow conditions
Solution Approach 1:
The cooling system is segmented into multiple functional zones: internal cooling channels for convective cooling, and peripheral cooling openings (first, second, and third sets) arranged in specific patterns to address different thermal zones. This segmentation allows targeted cooling of hot spots while maintaining overall temperature uniformity across the blade platform.
Solution Approach 2:
Different cooling strategies are applied to different regions of the blade platform. The first cooling openings are positioned at the periphery to address edge hot spots, the second set addresses central hot spots, and the third set provides additional targeted cooling. Each region receives cooling tailored to its specific thermal conditions and centrifugal force effects.
2Temperature
If more cooling openings are added to address hot spots, then temperature uniformity improves, but cooling fluid consumption increases
Solution Approach 1:
The cooling system utilizes the dynamic airflow environment within the turbine blade, where cooling fluid is strategically directed to follow flow paths that maximize cooling effectiveness. The peripheral cooling openings leverage the natural airflow patterns and centrifugal forces to distribute cooling fluid efficiently across the platform, reducing the total quantity needed while maintaining temperature uniformity.
Solution Approach 2:
The cooling system is designed to utilize the existing high-velocity airflow environment within the turbine blade to enhance cooling effectiveness. The peripheral cooling openings position cooling fluid in regions where natural airflow and centrifugal forces help distribute the cooling medium, allowing the system to leverage the operational environment rather than requiring additional active pumping or fluid injection.
3Reliability
If exotic heat-resistant materials are used to withstand high temperatures, then blade reliability improves, but manufacturing cost increases
Solution Approach 1:
The patent replaces reliance on exotic heat-resistant materials with a mechanical cooling system that actively removes heat from the blade platform. By using internal cooling channels and peripheral cooling openings to circulate cooling fluid, the system substitutes material-based thermal resistance with an active thermal management mechanism, allowing the use of more cost-effective, conventional materials while maintaining blade durability.
Solution Approach 2:
The cooling system changes the thermal parameters of the blade platform by actively controlling temperature distribution through regulated cooling fluid flow. By adjusting cooling fluid flow rates and distribution patterns, the system maintains the platform temperature within acceptable ranges, enabling the use of materials that would otherwise be unsuitable for such high-temperature environments.
4Temperature
If cooling channels are designed to maintain uniform temperature, then temperature uniformity improves, but centrifugal forces and airflow prevent adequate cooling in some areas
Solution Approach 1:
The patent adds a spatial dimension to the cooling strategy by positioning cooling openings at the periphery of the blade platform, where centrifugal forces and airflow patterns differ from the center. This peripheral positioning creates a three-dimensional cooling architecture that addresses the specific thermal-challenge zones created by centrifugal forces, allowing cooling fluid to be delivered where it is most needed despite the force field effects.
Solution Approach 2:
The peripheral cooling openings act as intermediaries that bridge the gap between the internal cooling channels and the external hot spot regions. These openings are strategically positioned to intercept and redirect cooling fluid to areas affected by centrifugal forces and airflow separation, serving as intermediate cooling points that enhance overall temperature uniformity while accounting for force field effects.
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 configuration enhances cooling efficiency, allows for the use of less exotic and cost-effective materials, reduces platform weight, and extends the lifespan of turbine blades by maintaining consistent temperatures and reducing hot spots, while minimizing cooling fluid consumption.
Implementation Method 1
The cooling medium may be a fluid and may form a layer of film cooling air immediately proximate to the outer surface of the platform
Implementation Method 2
This configuration of the cooling system cools the platform with both external film cooling and internal convection
Data Source
Figure 1
Figure 2
Figure 2a
AI summary
The cooling system for a turbine may include a plurality of platform cooling openings positioned in a platform of the turbine airfoil. In particular, the first set of cooling openings may create a first cooling path and a second set of cooling openings may be placed in the path of the first cooling path where the first cooling flow will cool the second set of cooling openings.