Helical Vane Entrainment System for Gas Turbine Mixing
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Solution Overview
Problem
Insufficient mixing of combustion products and cooling air in gas turbines leads to unfavorable temperature gradients, inefficiencies, and reliability issues, particularly in vortex burning combustion chambers and inter-turbine burners with short designs that limit mixing length.
Innovation Solution
An entrainment system with a helical flow path and radially disposed helical vanes within the gas turbine, increasing the residence time and mixing efficiency of combustion and non-combustion gases, featuring a DEEP TRENCH™ design with radial cavities and a canted V-shape profile to enhance turbulence and mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a short vortex burning combustion chamber design is used to decrease weight and size, then weight and size are reduced, but mixing length is insufficient resulting in poor mixing of combustion products and cooling air
Solution Approach 1:
The patent transforms the traditional axial flow path into a helical flow path, adding a rotational dimension to the mixing process. The helical vanes create a three-dimensional swirling motion that increases the effective mixing path length without extending the axial length of the combustion chamber, thereby maintaining compact size while improving mixing efficiency.
Solution Approach 2:
The patent employs curved helical surfaces instead of straight axial paths. The helical vanes create a curved flow path that forces the combustion products and cooling air to follow a spiral trajectory, increasing residence time and mixing effectiveness within the same physical space, thus resolving the contradiction between compact size and mixing efficiency.
2Device complexity
If a short vortex burning combustion chamber design is used to decrease device complexity, then device complexity is reduced, but mixing length is insufficient resulting in unfavorable temperature gradients
Solution Approach 1:
The helical flow path adds a rotational dimension to the mixing process, creating a three-dimensional flow pattern that enhances temperature uniformity without requiring a longer axial chamber. This dimensional transformation allows adequate mixing in a compact design, preventing thermal stresses while maintaining device simplicity.
3Device complexity
If primarily axial orientation for dilution air is used, then device complexity is reduced, but mixing efficiency is less than optimal due to insufficient mixing length
Solution Approach 1:
The patent replaces the straight axial flow orientation with a helical curved flow path. The helical vanes guide the dilution air through a spiral trajectory, increasing the effective mixing length and contact time between combustion products and cooling air. This curved path design maintains relative simplicity while dramatically improving mixing efficiency.
Solution Approach 2:
The invention transitions from a one-dimensional axial flow to a three-dimensional helical flow by adding rotational motion. This dimensional enhancement allows the dilution air to mix more thoroughly with combustion products along a longer effective path without significantly increasing the physical footprint or complexity of the device.
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 helical flow path results in a more uniform temperature profile, improving the efficiency and reliability of the turbine section by increasing the mixing of combustion and non-combustion gases, reducing thermal stresses and operability problems.
Implementation Method 1
each trench receives non-combustion gases from the first end of the axial body to the second end of the axial body in a helical flow path
Implementation Method 2
A profile or cross section of each trench has as a canted V-shape at the tip and widens into a parallelogram shape at the root, and a width of each trench increases along a length of each helical vane from the first end of the axial body to the second end of the axial body, to reduce losses and according to one embodiment of this invention. Each trench may include a tilt of a suitable angle to further facilitate turbulence and/or mixing.
Implementation Method 3
each trench radially receives combustion gases from the tip towards the root and each trench receives non-combustion gases from the first end of the axial body to the second end of the axial body in a helical flow path to quench the combustion gases with the non-combustion gases
Data Source
AI summary
This invention relates to an apparatus for an entrainment system of a vortex burning combustion chamber or a vortex burning inter-turbine burner in a gas turbine. The entrainment system rapidly and thoroughly mixes hot combustion gases with non-combustion gases to reduce the gas temperature before entering a turbine. The entrainment system includes a plurality of helical vanes forming trenches and resulting in a highly helical flow path. The highly helical flow path provides an increased residence time for mixing of the combustion gases and non-combustion gases. Radial cavities in the helical vanes, canted vane angles and varying geometries further facilitate mixing while reducing losses. This invention also includes a method of mixing combustion and non-combustion gases in an entrainment system.