Flame Port Unit Structure for Combustion Stability and NOx Reduction
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Solution Overview
Problem
The existing flame-hole structures in combustion apparatuses suffer from instability and increased NOx emissions due to the lifting phenomenon and uneven flame distribution, which affects combustion stability and carbon monoxide production.
Innovation Solution
A flame-hole structure with a lean flame-hole part and a rich flame-hole part, where the lean flame-hole part has constant and varying widths, and the rich flame-hole part is positioned on either side, with plates forming the flame-holes and protruding portions to ensure close contact and uniform heat transfer, stabilizing the lean and rich flames.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the number of lean flame-holes is increased to reduce NOx emission, then NOx emission is reduced, but a lifting phenomenon occurs due to decreased flame-hole width which significantly deteriorates flame stability
Solution Approach 1:
The patent applies local quality by creating different flame-hole width configurations in different regions. The lean flame-hole part has a first region with constant width and second regions with narrower widths, while the rich flame-hole part has varying widths. This localized variation in geometry allows the burner to maintain flame stability in critical areas while still achieving NOx reduction through increased total flame-hole count.
Solution Approach 2:
The burner is segmented into distinct functional regions: a lean flame-hole part with multiple lean flame-holes and a rich flame-hole part with a pair of rich flame-holes. Each region has specific width characteristics designed to address local combustion needs, allowing the system to balance NOx reduction with flame stability through spatial segmentation of the flame-hole structure.
2Object-generated harmful factors
If the width of lean flame-holes is decreased to increase the number of flame-holes, then NOx emission is reduced, but the jetting velocity becomes higher than burning velocity causing flame lifting and instability
Solution Approach 1:
The patent changes the geometric parameters of the flame-holes by creating multiple regions with different width characteristics. The lean flame-hole part includes a first region with constant width and second regions with narrower widths, while the rich flame-hole part has varying widths. This parameter variation allows optimization of the balance between jetting velocity and burning velocity to prevent flame lifting while maintaining high flame-hole count for NOx reduction.
3Shape
If rich flame-holes have non-constant widths with cut-off portions to improve flame distribution, then flame distribution is improved, but flame lifting occurs and stability is weakened
Solution Approach 1:
The patent applies local quality by creating different flame-hole width configurations in different regions. The lean flame-hole part has a first region with constant width and second regions with narrower widths, while the rich flame-hole part has varying widths. This localized variation in geometry allows the burner to maintain flame stability in critical areas while still achieving NOx reduction through increased total flame-hole count.
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 configuration reduces NOx emissions and enhances flame stability by maintaining a stable lean flame and rich flame, uniformly achieving a flame stabilizing effect across the combustion apparatus.
Implementation Method 1
A gas combustion apparatus refers to an apparatus for burning a supplied fuel gas to generate heat
Implementation Method 2
The rich flame refers to a flame generated when an air-fuel mixture (hereinafter, referred to as rich gas) with a relatively high fuel ratio is burned
Implementation Method 3
a tertiary flame is formed while unburned fuel of the rich flame reacts with excess air of the lean flame, and therefore the combustion stability of the lean flame may be enhanced
Data Source
AI summary
A flame port unit structure of a combustion apparatus provided with a plurality of flame ports for forming a flame comprises: a lean flame port unit, as a flame port for jetting lean gas, including a plurality of lean flame ports arranged along a width direction which is perpendicular to the jetting direction of the lean gas; and a rich flame port unit, as a flame port for jetting rich gas, including a pair of rich flame ports provided on both sides of the lean flame port unit with respect to a width direction, wherein the lean flame port unit comprises a first region in which a gap along the width direction of the lean flame port is formed along a longitudinal direction which is perpendicular to the jetting direction and the width direction, and a second region, provided on both sides along the longitudinal direction of the first region.