Lean-Rich Burner Port Layout for Stable Low-NOx Combustion
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Solution Overview
Problem
Existing burners face challenges in achieving stable combustion of lean mixtures while reducing nitrogen oxides (NOx) and carbon monoxide (CO) emissions, as the arrangement of lean and rich flame burner ports limits the effectiveness of flame holding and combustion stability, leading to unstable combustion and excessive emissions.
Innovation Solution
The burner design incorporates a laminated structure with lean flame burner ports in the center and rich flame burner ports on either side, where the rich flames surround the lean flames, creating a pseudo-circumferential flame holding pattern to stabilize the lean combustion and reduce NOx and CO emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If lean mixtures are combusted to reduce NOx emissions, then nitrogen oxides emissions are reduced, but combustion stability deteriorates
Solution Approach 1:
Rich flame burner ports act as an intermediary mechanism, providing stable combustion zones that anchor and support the lean flame combustion, thereby maintaining overall combustion stability while allowing lean mixtures to be burned in the central ports for NOx reduction
Solution Approach 2:
The burner ports are segmented into two distinct types: central lean flame ports for low NOx emission and side rich flame ports for stability. This segmentation allows each zone to perform its specific function optimally without interfering with the other
2Reliability
If rich flame burner ports are arranged on either side of lean flame burner ports, then flame holding effect is obtained, but the distance between rich and lean flame ports reduces the holding effectiveness
Solution Approach 1:
The burner port arrangement uses asymmetric positioning where rich flame ports are placed at specific distances and angles relative to the central lean flame ports, optimizing the flame interaction geometry to maximize holding effectiveness despite the necessary separation distance
3Ease of manufacture
If metallic plates are used to form burner ports, then manufacturing is simplified, but the shapes and arrangements of burner ports are limited
Solution Approach 1:
The invention uses thin plate structures with formed shapes that can be bent and shaped into complex three-dimensional configurations, allowing versatile burner port arrangements while maintaining the manufacturing simplicity of press-working processes
4Shape
If lean flame burner ports are placed in the middle and rich flame burner ports on the sides, then structural symmetry is achieved, but combustion controllability is reduced
Solution Approach 1:
The burner design applies local quality by giving different functional characteristics to different regions: the central region uses lean flame ports for clean combustion while the peripheral regions use rich flame ports for stability, allowing optimized performance in each local zone rather than uniform design
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 design enhances flame holding stability, widens the range of air/fuel ratios for stable combustion, reduces NOx and CO emissions, and improves combustion controllability, resulting in a compact burner with high output power.
Implementation Method 1
On the first burner port, a first mixture is combusted to generate a first flame... The second burner ports are arranged on either side of the gap and combust a second mixture, to generate second flames and hold the first flame
Data Source
AI summary
A burner includes a first burner port that generates a first flame, a gap that surrounds the first burner port, and a plurality of second burner ports that are disposed on either side of the gap, the second burner ports generating second flames to hold the first flame. The first burner port combusts a first mixture (lean mixture) to generate the first flame (lean flame). The first mixture includes air more than fuel gas. A gap that surrounds the first burner port is formed. A plurality of the second burner ports are arranged on either side of the gap. The second burner ports combust a second mixture (rich mixture) to generate the second flames (rich flames) and hold the first flame. The air-fuel ratio of the second mixture is smaller than the first mixture.