Driver-Jet Combustor Geometry for Stable Gas Turbine Vortices
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Solution Overview
Problem
Existing gas turbine combustors face challenges in maintaining combustion efficiency while reducing length and weight, particularly in vortex combustors where stability of untrapped vortices and low pattern factor are difficult to achieve, leading to potential damage to downstream turbine hardware.
Innovation Solution
The use of driver airflow jets and shaped driver holes or slots in the combustor to stabilize toroidal vortices, combined with thicker liners and vanes, enhances vortex stability and reduces circumferential temperature variation, optimizing combustion performance and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of stationary object
If the combustor length is reduced to decrease weight, then weight is reduced, but combustion efficiency and vortex stability deteriorate
Solution Approach 1:
The patent changes the geometric parameters of driver holes (length-to-diameter ratio, inlet curvature radius, chamfer dimensions) to optimize airflow jet characteristics. By carefully controlling these parameters, the combustor achieves stable vortex formation and maintained combustion efficiency in a shortened configuration, resolving the contradiction between reduced weight and maintained reliability.
Solution Approach 2:
The patent introduces inlet curvature at the driver hole entrance with a specific radius-to-diameter ratio. This curvature modification to the hole geometry stabilizes the airflow jet and enhances vortex formation, allowing the shortened combustor to maintain combustion efficiency despite the reduced length.
2Manufacturing precision
If driver hole length-to-diameter ratio is increased to improve discharge coefficient, then discharge coefficient improves, but manufacturing complexity increases
Solution Approach 1:
The patent optimizes the driver hole geometry by specifying a length-to-diameter ratio within a particular range and introducing inlet curvature with controlled dimensions. These parameter adjustments improve the discharge coefficient and flow stability while keeping the holes manufacturable through conventional drilling and machining processes.
Solution Approach 2:
The inlet curvature feature is designed with a radius that is a specific fraction of the hole diameter. This curved inlet geometry improves flow attachment and discharge characteristics while remaining compatible with standard manufacturing capabilities through CNC machining or precision drilling operations.
3Stability of the object's composition
If liner thickness is increased to stabilize vortices, then vortex stability improves, but combustor weight increases
Solution Approach 1:
The patent applies local thickening of the liner only at specific locations where driver holes are positioned, rather than uniformly increasing the entire liner thickness. This localized approach provides the necessary structural support and flow stabilization while minimizing the overall weight increase of the combustor assembly.
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 approach allows for a shorter, lighter combustor with improved combustion efficiency, reduced pattern factor, and lower thermal stress on downstream components, resulting in fuel savings and reduced cooling needs.
Implementation Method 1
stabilize toroidal vortices
Implementation Method 2
driver airflow jets
Implementation Method 3
fuel and ignited to generate combustion gases
Data Source
AI summary
A combustor including a dome structure, an inner liner and an outer liner connected to the dome structure to define a combustion chamber, and a first segment coupled to the outer liner and a second segment coupled to the inner liner, the first segment including a first geometric ramp and the second segment including a second geometric ramp. The first geometric ramp and the second geometric ramp have one or more driver holes, driver slots, and/or a plurality of driver vanes. An upstream crossflow enters the one or more driver holes, driver slots, and/or the plurality of driver vanes to generate an airflow jet having an increased angle at an exit of the one or more to driver holes, driver slots, and/or the plurality of driver vanes relative to a surface of the inner liner or a surface of the outer liner.