Nested Flame Stabilizers for Combustion Burner Ignition
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Solution Overview
Problem
Conventional combustion burners face issues with flame stability and ignition interference due to the size and number of flame stabilizers, leading to fluctuations in fuel gas flow rate and concentration, which can obstruct ignition and affect combustion efficiency.
Innovation Solution
A combustion burner design featuring a fuel nozzle with a ring-shaped first flame stabilizer and a second flame stabilizer inside, both separated by a predetermined space, to create a recirculation area without interference, ensuring stable combustion and broad ignition throughout the fuel nozzle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the size of the flame stabilizer is increased or the number of flame stabilizers is increased to improve flame stability, then flame stabilizing performance is improved, but the blockage rate at the leading end of the fuel nozzle increases and flow rate fluctuations occur
Solution Approach 1:
The patent employs nested flame stabilizers where a first flame stabilizer and a second flame stabilizer are arranged concentrically along the axial direction. The first flame stabilizer has a larger outer diameter and is positioned upstream, while the second flame stabilizer has a smaller outer diameter and is positioned downstream. This nested configuration allows multiple flame stabilizing surfaces without significantly increasing the blockage area at the nozzle leading end, as the stabilizers share the same radial space rather than occupying separate lateral positions.
Solution Approach 2:
The patent transitions from a single-plane flame stabilizer configuration to a multi-dimensional arrangement by positioning flame stabilizers at different axial locations and with different radial dimensions. The first flame stabilizer is disposed at a first position from the leading end, while the second flame stabilizer is disposed at a second position further from the leading end, creating axial separation. This dimensional arrangement allows the fuel gas flow to be stabilized at multiple points along the flow path without creating lateral interference between stabilizers.
2Reliability
If the size of the flame stabilizer is increased, then flame stabilizing performance is improved, but ignition interference occurs due to increased flow rate in the vicinity of igniters
Solution Approach 1:
The patent divides the flame stabilizing function into multiple separate components: a first flame stabilizer and a second flame stabilizer, each with distinct positions and dimensions. This segmentation allows the ignition process to occur at the first stabilizer without being immediately affected by the second stabilizer downstream, reducing ignition interference. The separated configuration ensures that flow rate increases at one stabilizer do not directly impact the ignition environment at another stabilizer.
Solution Approach 2:
The patent introduces an intermediate space between the first flame stabilizer and the second flame stabilizer along the axial direction. This intermediate region acts as a buffer zone where the fuel gas flow can be conditioned between the two stabilizers, preventing direct interference between their respective flow fields. The spatial separation ensures that ignition at the first stabilizer does not create harmful flow rate increases that would interfere with the second stabilizer's operation.
3Reliability
If the number of flame stabilizers is increased, then flame distribution evenness is improved, but guide surfaces are insufficient due to crossing flame stabilizers
Solution Approach 1:
The patent uses a nested configuration where the second flame stabilizer is positioned within the radial envelope of the first flame stabilizer. This nesting arrangement ensures that the flame stabilizers do not cross each other, maintaining sufficient guide surfaces on the outer periphery of both stabilizers. The concentric arrangement allows multiple stabilizers to coexist without lateral interference, preserving the geometric integrity needed for even flame distribution.
Solution Approach 2:
The patent resolves the complexity issue by arranging flame stabilizers in the axial dimension rather than the radial dimension. The first flame stabilizer is positioned at a first axial location, while the second flame stabilizer is positioned at a second axial location further from the nozzle leading end. This axial separation prevents the flame stabilizers from crossing each other in the radial direction, ensuring that guide surfaces remain sufficient and the configuration remains manageable despite having multiple stabilizers.
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 stabilizing performance by preventing ignition interference and maintaining even flame distribution across the flame stabilizers, improving combustion efficiency and reducing NOx production.
Implementation Method 1
a recirculation area is formed on the downstream side of the first flame stabilizer main body and, as a result, the fuel gas flowing in the fuel nozzle can maintain the combustion of the fuel
Data Source
AI summary
In this combustion burner and boiler, interference of ignition in a flame stabilizer is suppressed and flame stabilizing performance is improved by providing: a fuel nozzle which ejects a fuel gas that is a mixture of pulverized coal and air; a combustion air nozzle which ejects a fuel gas combustion air from outside of the fuel nozzle; a secondary air nozzle which ejects secondary air from the outside of the combustion air nozzle; and a flame stabilizer which comprises a first flame stabilizer main body which is arranged at the leading end of the fuel nozzle and separated by a prescribed space from the inner wall surface of the fuel nozzle and which forms a ring shape having as the center an axial line along the ejection direction of the fuel gas.