Compact Gas Turbine Combustor with Baffle Plate Flow Control
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Solution Overview
Problem
Existing gas turbine combustor designs face challenges in reducing NOx emissions while maintaining a compact size, as increasing combustor length increases weight and cost, and shortening the distance between the turning portion and fuel mixing position leads to increased NOx generation and air distribution deflection.
Innovation Solution
A combustor design featuring a pilot nozzle with main nozzles arranged circumferentially, an inner cylinder surrounding the pilot nozzle, and an outer cylinder forming a compressed air passage that turns the flow direction, utilizing a baffle plate with varying hole diameters to control flow rates and prevent separation, along with a top hat nozzle and stirrers to enhance turbulence and fuel mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the combustor length is increased to provide sufficient flow rectifying distance, then flow uniformity and NOx reduction are improved, but weight and cost increase
Solution Approach 1:
The baffle plate is designed with non-uniform hole distribution, where the density and/or diameter of holes vary in different regions. This creates localized flow rate adjustments that compensate for the shortened rectifying distance, enabling uniform flow distribution without increasing overall combustor length, thereby reducing weight while maintaining NOx reduction performance
Solution Approach 2:
The invention changes the geometric parameters of the baffle plate (hole diameter, hole density, hole pattern) to optimize flow distribution. By adjusting these parameters, the system achieves sufficient flow rectification in a compact configuration, resolving the contradiction between combustor length/weight and flow uniformity for NOx control
2Stability of the object's composition
If the combustor length is increased to reduce air separation, then flow uniformity is improved, but device complexity and size increase
Solution Approach 1:
Rather than using a long combustor for gradual flow rectification, the invention employs a baffle plate with spatially varying hole characteristics that locally adjust flow rates to achieve uniform distribution. This reduces the required combustor length and simplifies the overall structure while maintaining flow stability
Solution Approach 2:
The baffle plate acts as an intermediary flow control device that actively manages air separation and flow distribution. By positioning and designing the baffle plate with specific hole patterns, the system achieves flow uniformity without requiring increased combustor length or complex multi-component structures
3Volume of moving object
If the distance from turning portion to fuel mixing position is shortened to compact the combustor, then size is reduced, but air distribution deflection increases and NOx generation increases
Solution Approach 1:
The baffle plate incorporates non-uniform hole distribution with varying density and/or diameter across different regions. This local variation compensates for the reduced distance from the turning portion, ensuring uniform flow reaches the fuel mixing position even in a compact configuration, thereby preventing NOx generation while maintaining small combustor volume
Solution Approach 2:
The baffle plate performs preliminary flow rectification and uniformization before the air reaches the fuel mixing position. By pre-adjusting the flow distribution through its non-uniform hole pattern, the system compensates for the shortened distance, ensuring proper mixing conditions are achieved despite the compact 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 achieves NOx reduction while maintaining a compact size by preventing air separation and ensuring uniform fuel concentration, thereby improving combustion efficiency and reducing emissions.
Implementation Method 1
the compressed air passage is provided with a flow rate controller that makes the flow rate on the combustor inner peripheral side of the passage larger than that on the outer peripheral side of the passage
Implementation Method 2
turning the flow direction of compressed air flowing in the compressed air passage in approximately the opposite direction at the end of the inner cylinder to introduce the compressed air into the pilot nozzle
Implementation Method 3
a pilot nozzle disposed along the central axis of the combustor and performing diffusion combustion
Implementation Method 4
a plurality of main nozzles disposed on the outer peripheral side of the pilot nozzle at intervals in the circumferential direction and performing premixed combustion
Data Source
AI summary
Provided is a combustor that is made compact and achieves NOx reduction. In the combustor (1) including a pilot nozzle (21) disposed along the central axis of the combustor (1) and performing diffusion combustion, a plurality of main nozzles (22) disposed on the outer peripheral side of the pilot nozzle (21) at intervals in the circumferential direction and performing premixing combustion, a single inner cylinder (2a) surrounding the pilot nozzle (21) and the main nozzles (22), and an outer cylinder approximately coaxially surrounding the outer side of the inner cylinder (2a) to form a compressed air passage (6) between the inner peripheral surface thereof and the outer peripheral surface of the inner cylinder and turning the flow direction of compressed air flowing in the compressed air passage (6) in approximately the opposite direction at the end of the inner cylinder (2a) to introduce the compressed air into the pilot nozzle (21), the compressed air passage (6) is provided with a flow rate controller that makes the flow rate on the combustor (1) inner peripheral side of the passage larger than that on the outer peripheral side. An example as the flow rate controller is a baffle plate 51 provided with holes 55, 56.