Combustor Ejection Tube Design to Reduce Nitrogen Oxide Emissions
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Solution Overview
Problem
Existing combustors suffer from low combustion efficiency and high nitrogen oxide generation.
Innovation Solution
A combustor design featuring multiple flame distributors with specific ejection tube configurations, including ejection and diffusion sections, diverter angles, and gas distribution devices to enhance gas mixing and reduce nitrogen oxide emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional combustor design is used, then structure is simple, but combustion efficiency is low and nitrogen oxide emissions are high
Solution Approach 1:
The combustor is divided into multiple flame distributors (at least three) arranged side by side, each with separate ejection tubes. This segmentation allows independent optimization of each flame distributor's gas flow and mixing characteristics, improving overall combustion efficiency while distributing and reducing nitrogen oxide generation across multiple smaller combustion zones
Solution Approach 2:
Each ejection tube features locally optimized geometry with specific dimensions (throat width D1, ejection section length H1 where 8.5D1≤H1≤9.5D1, diverter angle 45°-85°) to create ideal gas flow patterns. The premixing section (length H11 where 2D1≤H11≤3D1) and diffusion section (length H12 where 3.5D1≤H12≤4.5D1) are designed with different cross-sectional characteristics to optimize mixing at each location, achieving high combustion efficiency with reduced nitrogen oxide emissions
2Stability of the object's composition
If ejection section length H1 is increased to improve mixing, then gas mixing efficiency improves, but device complexity increases
Solution Approach 1:
The ejection tube dimensions are precisely controlled within specific ranges (H1 between 8.5D1 and 9.5D1, H11 between 2D1 and 3D1, H12 between 3.5D1 and 4.5D1) to achieve optimal gas mixing uniformity. By establishing quantitative parameter relationships rather than arbitrary dimensions, the design achieves high mixing efficiency while maintaining manufacturability and avoiding excessive complexity
3Productivity
If multiple flame distributors are added to improve combustion, then combustion efficiency improves, but device complexity increases
Solution Approach 1:
The combustor employs multiple flame distributors arranged side by side, with each distributor containing at least three ejection tubes. This segmentation into modular units improves combustion efficiency by creating multiple combustion zones with better air-fuel mixing, while the standardized modular design keeps structural complexity manageable through repetition of identical components
Solution Approach 2:
Multiple flame distributors are combined within a single combustor body, with each distributor handling a portion of the total gas flow. This merging of multiple combustion functions into one integrated device achieves high overall combustion efficiency while maintaining a compact structure that doesn't linearly increase complexity with the number of flame distributors
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
Improves combustion efficiency and significantly reduces nitrogen oxide emissions by optimizing gas flow and mixing, achieving a reduction from 80ppm to 20ppm.
Implementation Method 1
a diffusion section, gradually deviating from a central axis of each of the at least three ejection tubes along a gas flow direction
Implementation Method 2
a diverter, provided in the gas outlet section, having an apex corner for diverting gas towards two sides, the angle of the apex corner being 45 degrees to 85 degrees
Implementation Method 3
A water heater or a wall-mounted furnace is household equipment which takes fuel gas as a main energy source and provides domestic hot water or household heating
Data Source
Figure 1
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Figure 3
AI summary
A combustor and a water heater using the same. The combustor (10) comprises a plurality of flame distributors (100) which are arranged side by side in the width direction, each flame distributor (100) comprises at least three ejection tubes (110), and each ejection tube (110) is sequentially provided with an ejection section (110A) and an gas outlet section (110B) along the gas flow direction. Each ejection tube (110) comprises a throat (114) and a diverter (112). The throat (114) is provided at the minimum cross-section of the ejection section (110A), the length of the ejection section (110A) is H1, and the maximum width of the throat (114) allowing gas to pass is D1, wherein 8.5D1≤H1≤9.5D1. The diverter (112) is provided in the gas outlet section (110B) and has a top corner (112C) for diverting gas to two sides, and the angle of the top corner (112C) is 45 degrees to 85 degrees.