Helicoidal Rib Duct Assembly for Gas Turbine Combustor Cooling
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Solution Overview
Problem
The existing duct assembly structure for gas turbines has limited cooling efficiency due to unidirectional flow characteristics of compressed air, which restricts the cooling effectiveness of the liner exposed to high-temperature combustion gases.
Innovation Solution
A helicoidal structure is introduced, featuring a helicoidal rib that protrudes from the liner surface to guide cooling air at a predetermined angle, creating a first cooling passage and a second cooling passage through cooling holes, enhancing the residence time and cooling area of compressed air on the liner surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If unidirectional flow characteristics are used for compressed air cooling, then the structure is simple, but the cooling efficiency is limited
Solution Approach 1:
The patent applies helicoidal (spiral) curvature to the flow passage structure through the helicoidal rib, transforming the linear unidirectional flow into a curved vortex flow pattern. This curvature increases the residence time of cooling air along the liner surface and enhances cooling efficiency without requiring multiple separate cooling systems
Solution Approach 2:
The helicoidal rib introduces a third dimension (helical angle) to the traditionally two-dimensional axial flow passage. By adding the helical dimension, the cooling air gains rotational motion components that increase its path length and contact time with the liner surface, thereby improving cooling efficiency
2Quantity of substance
If limited compressed air is used for cooling, then the resource consumption is reduced, but the cooling area and residence time are insufficient
Solution Approach 1:
The helicoidal rib creates a vortex flow pattern that extends the cooling air path in a helical manner along the liner surface. This curved path increases the effective cooling area covered by the limited compressed air and prolongs the residence time without requiring additional air quantity
Solution Approach 2:
The helicoidal structure ensures continuous contact of cooling air with the liner surface along the entire helical path, maximizing the utilization of limited compressed air. The vortex flow prevents dead zones and ensures continuous cooling action throughout the combustion chamber
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 diversifies the flow passage, generating vortex currents that maximize cooling efficiency by increasing the residence time and cooling area of compressed air on the liner surface, thereby improving the overall cooling performance.
Implementation Method 1
This configuration diversifies the flow passage, generating vortex currents that maximize cooling efficiency by increasing the residence time and cooling area of compressed air on the liner surface
Implementation Method 2
the cooling holes induce a flow of the auxiliary-cooling compressed air through the cooling holes, and the flow of the auxiliary-cooling compressed air is derived from a flow of the main-cooling compressed air in the first cooling passage
Data Source
AI summary
A helicoidal structure promotes cooling of a liner applied in an annular space of a double-shell structure formed of the liner and a flow sleeve to cool a duct assembly, by increasing the residence time and cooling area of cooling compressed air on the surface of the liner. The helicoidal structure includes a helicoidal rib protruding from a surface of the liner to guide the cooling compressed air at a predetermined angle with respect to an axial direction of the liner, the helicoidal rib having cooling holes and forming a first cooling passage along which main-cooling compressed air flows and a second cooling passage along which auxiliary-cooling compressed air flows. The second cooling passage induces a flow of the auxiliary-cooling compressed air through the cooling holes, and the flow of the auxiliary-cooling compressed air is derived from a flow of the main-cooling compressed air in the first cooling passage.