Scroll Cooling Flow Path Segmentation for Gas Turbines
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Solution Overview
Problem
In gas turbine facilities, particularly CO2 turbines, it is challenging to effectively cool the scroll due to thermal resistance and deformation issues, as the temperature difference between the high-temperature combustion gas and low-temperature cooling medium is significant, making it difficult to sufficiently cool the entire scroll.
Innovation Solution
The introduction of a dividing part at the scroll inner cylinder divides the cooling medium flow path, allowing it to branch into inner and outer ring side flow paths, ensuring that the cooling medium is efficiently distributed to both the inner and outer radial portions of the scroll, thereby improving cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the scroll is made thicker to prevent deformation and reduce thermal resistance, then structural strength and thermal conductivity improve, but cooling efficiency deteriorates because the temperature difference between combustion gas side and cooling medium side becomes too large
Solution Approach 1:
The scroll is divided into multiple cooling flow path regions (first cooling flow path and second cooling flow path) with different thicknesses. The first cooling flow path has a greater thickness to handle higher thermal loads, while the second cooling flow path has a smaller thickness to maintain effective cooling. This segmentation allows the scroll to have both structural strength and cooling efficiency in different regions.
2Temperature
If conventional cooling methods (impingement cooling, convection cooling) are used, then cooling is provided to the scroll, but cooling efficiency is insufficient and the entire scroll cannot be effectively cooled
Solution Approach 1:
The cooling flow path is segmented into multiple regions (first cooling flow path and second cooling flow path) that branch from the introduction flow path. This segmentation allows different regions of the scroll to receive cooling medium through separate paths, ensuring comprehensive cooling coverage and improving cooling reliability throughout the entire scroll structure.
Solution Approach 2:
Different regions of the scroll are provided with cooling flow paths having different characteristics. The first cooling flow path and second cooling flow path are configured with different thicknesses and flow characteristics to match the local thermal requirements of different scroll regions, optimizing cooling efficiency throughout.
3Device complexity
If a single cooling flow path is used, then the structure is simple, but the cooling medium cannot be efficiently distributed to both inner and outer radial portions of the scroll
Solution Approach 1:
The cooling flow path is divided into multiple segments (first cooling flow path and second cooling flow path) that branch from a common introduction flow path. This segmentation enables the cooling medium to be distributed to different radial portions of the scroll (inner and outer regions) through separate flow paths, achieving uniform cooling distribution while maintaining a relatively simple overall structure.
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 the cooling reliability of the scroll by ensuring that both the inner and outer radial portions are effectively cooled, reducing thermal stress and preventing deformation.
Implementation Method 1
the scroll is cooled by a cooling medium as hot combustion gas passes therethrough
Implementation Method 2
it has been proposed that the scroll can be cooled by cooling methods such as impingement cooling and convection cooling
Data Source
AI summary
An entire scroll is effectively cooled. A scroll of an embodiment leads combustion gas to a turbine stage as a working medium for driving a turbine rotor in a gas turbine facility, and includes a scroll inner cylinder and a scroll outer cylinder. The working medium flows into the scroll inner cylinder. The scroll outer cylinder is provided to cover the scroll inner cylinder with a scroll cooling flow path therebetween where a cooling medium with a temperature lower than the working medium is supplied. The scroll cooling flow path includes an inner ring side flow path part located inside than the scroll inner cylinder in a radial direction of the turbine rotor and an outer ring side flow path part located outside than the scroll inner cylinder in the radial direction of the turbine rotor. Here, a dividing part dividing the outer ring side flow path part in an axial direction along a rotation axis of the turbine rotor is provided at the scroll inner cylinder.