Turbine Blade Cooling via Bypass and Local Quality
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Solution Overview
Problem
The cooling capacity of the cooling fluid in turbine blades decreases as it flows downstream through serpentine passages, leading to potential overcooling or insufficient cooling due to the provision of a bypass portion, which can result in decreased turbine efficiency and risk of blade damage.
Innovation Solution
A turbine blade design that includes a bypass portion in the partition wall between adjacent cooling passages, allowing communication between upstream and downstream passages, with varying parameters such as cooling hole pitch, diameter, and turbulator height between upstream and downstream regions to optimize cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a bypass portion is provided in the serpentine passages to supply cooling fluid before temperature rises, then cooling capacity is improved at downstream locations, but temperature difference between before and after bypass becomes large causing overcooling or insufficient cooling
Solution Approach 1:
The patent applies local quality by providing different configurations of cooling holes, turbulators, or thermal barrier coating at different locations along the serpentine passage. Specifically, the number, size, or distribution of cooling holes varies between upstream and downstream regions, allowing optimized cooling performance at each location without causing overcooling or insufficient cooling.
Solution Approach 2:
The patent changes parameters such as the number of cooling holes, their diameters, spacing, or the presence and characteristics of turbulators at different positions along the serpentine passage. These parameter variations enable the cooling system to adapt to changing temperature conditions along the passage length, maintaining optimal cooling efficiency throughout.
2Area of stationary object
If cooling fluid flows through serpentine passages, then cooling coverage is improved, but cooling capacity decreases at downstream locations due to temperature rise
Solution Approach 1:
The serpentine passage is segmented into multiple sections with different cooling configurations. By dividing the continuous cooling path into distinct zones with varying cooling hole densities, turbulator placements, or thermal barrier characteristics, the system maintains effective cooling capacity throughout the entire passage while covering a large area.
Solution Approach 2:
Different segments of the serpentine passage are given different local qualities in terms of cooling hole configuration, turbulator presence, or thermal barrier properties. This allows each section to be optimized for its specific thermal conditions while contributing to overall comprehensive cooling coverage.
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 design effectively prevents overcooling or insufficient cooling by supplying cooling fluid at a relatively low temperature to the downstream region through the bypass, maintaining optimal cooling efficiency and preventing blade damage.
Implementation Method 1
cooling the turbine blade exposed to a high-temperature gas flow by allowing a cooling fluid to flow through serpentine passages
Implementation Method 2
cooling the turbine blade exposed to a high-temperature gas flow or the like by allowing a cooling fluid to flow through serpentine passages formed inside the turbine blade
Implementation Method 3
a plurality of fins (turbulators) for promoting turbulence of a flow of the cooling fluid in the cooling passage
Data Source
AI summary
A turbine blade includes a blade body, cooling passages extending in the blade height direction inside the blade body and connected to each other via folded portions, and a bypass portion that is provided in a partition wall portion partitioning a pair of adjacent cooling passages and that allows the pair of cooling passages to communicate with each other. The pair of cooling passages includes an upstream passage and a downstream passage. The turbine blade is provided with: a plurality of cooling holes formed in the blade body so as to be arranged along the blade height direction, that communicate with the downstream passage, and open in the surface of the blade body; a plurality of turbulators provided on the inner wall surface of the downstream passage and arranged along the blade height direction; or a thermal barrier coating that covers the surface of the blade body.