Turbine Blade Cooling Passage Geometry to Limit Stress Concentration
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Solution Overview
Problem
Conventional turbine blades experience stress concentration and potential damage due to flow channel changes in cooling holes, which affects their cooling performance and manufacturing efficiency.
Innovation Solution
A turbine blade design featuring a cooling passage with a first cooling hole of constant diameter and a second cooling hole with an increased diameter, where the two holes communicate without a level difference, and multiple cooling passages are disposed along the blade height direction, optimized through electrolytic machining techniques to enhance cooling efficiency and manufacturing precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a flow channel change part with varying diameter is disposed at a predetermined position in the cooling hole, then cooling performance is improved, but stress concentration is caused which may cause damage to the turbine blade
Solution Approach 1:
The patent applies parameter changes by transitioning from a constant diameter cooling hole to a variable diameter cooling hole with a flow channel change part. The diameter parameter is changed along the longitudinal direction to optimize cooling performance while managing stress distribution. This is achieved by carefully controlling the diameter variation to prevent stress concentration while maintaining effective cooling.
Solution Approach 2:
The patent applies local quality by creating a flow channel change part with different diameter characteristics at specific positions within the cooling hole. The diameter is varied locally along the longitudinal direction to provide enhanced cooling where needed while maintaining structural integrity in other regions. This localized modification allows optimization of cooling performance without compromising overall blade strength.
2Temperature
If multiple cooling passages with different diameter configurations are provided, then cooling efficiency is improved, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the cooling system into multiple cooling passages, each with specific diameter configurations. The cooling holes are segmented into different sections (constant diameter part and variable diameter part) to perform different cooling functions. This segmentation allows for optimized cooling in different regions of the turbine blade while maintaining manageable complexity through systematic design.
Solution Approach 2:
The patent applies universality by designing cooling passages that serve multiple functions. The same cooling passage structure with variable diameter serves both cooling purposes and stress management functions. The flow channel change part not only improves cooling efficiency but also helps in managing stress distribution, making the structure multi-functional and reducing overall device 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
The design improves cooling performance by efficiently cooling the blade, particularly at high heat load areas, while preventing stress concentration and facilitating efficient manufacturing of the turbine blade.
Implementation Method 1
forming a first cooling hole by electrolytic machining, the first cooling hole having an inner diameter that is constant along a blade height direction from a front end toward a base end of the turbine blade; and forming a second cooling hole by electrolytic machining while changing at least one of a current value and a machining speed
Data Source
AI summary
To provide a turbine blade, a manufacturing method for a turbine blade, and a gas turbine. In the turbine blade including a cooling passage provided along a blade height direction, the cooling passage includes: a first cooling hole including one end opening toward a front end, and having an inner diameter that is constant along the blade height direction; and a second cooling hole including one end communicating with the other end of the first cooling hole without a level difference, and having an inner diameter that is increased toward a base end. A length from the one end of the first cooling hole to a position where the first cooling hole and the second cooling hole are communicated with is 40% to 60% of a length from the one end of the first cooling hole to a gas path surface on the base end.