Gas Turbine Combustor Swirling Flow and Segmentation
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Solution Overview
Problem
Small-sized gas turbine combustors face challenges in achieving stable high-load combustion, high combustion efficiency, low CO concentration, and low NOx emissions due to their limited volume, which hinders their effectiveness in home electric generation devices.
Innovation Solution
A gas turbine combustor design featuring a concentric and cylindrical structure with a swirling air flow forming device, a fuel ejector, and an igniter to create a premixed swirling flow, along with an annular restrictor and diluting air holes, which forms a tubular flame and enhances combustion stability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the combustion chamber volume is reduced to achieve a small-sized gas turbine, then the device size is reduced, but stable high-load combustion and high combustion efficiency cannot be achieved
Solution Approach 1:
The invention divides the combustion chamber into multiple zones: a primary combustion zone with intense mixing and a secondary combustion zone for complete combustion. This segmentation allows each zone to perform its specific function optimally, enabling stable high-load combustion in a compact overall volume.
Solution Approach 2:
The invention transitions from conventional planar mixing to three-dimensional swirling flow structure. The swirl injector creates a vortex flow that enhances mixing in the radial, axial, and tangential directions simultaneously, achieving superior combustion efficiency in a smaller volume.
2Volume of moving object
If the combustion chamber volume is reduced, then the device size is reduced, but CO and NOx emissions increase
Solution Approach 1:
The combustion process is divided into two stages: primary combustion with controlled mixing in the first zone, and secondary combustion with complete mixing in the second zone. This two-stage approach ensures complete fuel consumption (reducing CO) while controlling peak temperatures (reducing NOx) in a compact chamber.
Solution Approach 2:
The invention changes the flow parameters through swirl injection, creating a vortex flow that extends the residence time of combustion products and improves mixing efficiency. This allows complete combustion at lower peak temperatures, reducing harmful emissions in a small chamber.
3Device complexity
If a conventional combustor structure is used, then the structure is simple, but operational stability and cleanliness of exhaust deteriorate
Solution Approach 1:
The invention introduces a dynamic swirling flow structure that adapts to combustion conditions. The swirl-generated vortex creates a stable recirculation zone that maintains operational stability and promotes complete combustion, improving exhaust cleanliness despite the added structural complexity of the swirl injector.
4Volume of moving object
If the combustion chamber is made compact, then the device size is reduced, but flame stability and diffusion are compromised
Solution Approach 1:
The swirl injector creates a three-dimensional vortex flow structure that maintains flame stability through centrifugal forces and recirculation zones. This dynamic flow structure ensures proper fuel-air mixing and flame anchoring in a compact volume, preserving flame stability despite the reduced chamber size.
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 design enables stable high-load combustion, high combustion efficiency, and low CO and NOx concentrations even in small-sized combustion chambers, preventing wall deposits and improving flame stability and diffusion.
Implementation Method 1
a swirling air flow forming device introducing combustion air into the vicinity of the end liner in the combustion chamber from the outside and forming a swirling air flow surrounding the center axis
Implementation Method 2
a fuel ejector ejecting fuel in the swirling direction of the swirling air flow to form a premixed swirling flow
Implementation Method 3
an igniter igniting the premixed swirling flow to form a tubular flame surface
Implementation Method 4
a diluting air hole supplying diluting air along a flow of combustion gas passing through the restrictor
Data Source
Figure 1~2
Figure 3A~3C
Figure 4
AI summary
A gas turbine combustor is provided which can accomplish stable high-load combustion, high combustion efficiency, a low concentration of CO, and NOx in a small-sized combustion chamber. The gas turbine combustor includes an inner liner 12 and an outer liner 14 being concentric and cylindrical and an end liner 16 closing between upstream ends thereof and forms a hollow cylindrical combustion chamber 18 therein. The gas turbine combustor further includes a swirling air flow forming device 22 introducing combustion air 7a into the vicinity of the end liner in the combustion chamber 18 from the outside and forming a swirling air flow, a fuel ejector 24 ejecting fuel 8 in the swirling direction to form a premixed swirling flow, and an igniter 26 igniting the premixed swirling flow to form a tubular flame surface 11. The combustion chamber 18 includes a primary combustion chamber 18a disposed close to the end liner, a secondary combustion chamber 18b disposed downstream of the primary combustion chamber, and an annular restrictor 19 reducing the outer diameter of the primary combustion chamber and being disposed therebetween. A diluting air hole 30 supplying diluting air along a flow of the combustion gas passing through the restrictor is disposed downstream of the restrictor 19 in the inner liner 12.