Vaporiser Element Air Inlet Extension for Evaporative Burner
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Solution Overview
Problem
Existing evaporator assemblies for evaporative burners suffer from inefficient mixing of air and fuel vapor, leading to high pollutant emissions, particularly NOx, which do not meet stringent emission standards for both vehicle and building heating systems.
Innovation Solution
The design features a housing with a peripheral wall and bottom wall, where the air inlet extension is without radial openings, and a swirl device is provided upstream to maintain axial flow, ensuring that air with swirl enters the combustion chamber, where the peripheral wall is partially covered with porous evaporator medium for enhanced mixing, reducing pollutant emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the air inlet attachment has slots in its peripheral wall to allow air to flow radially outward, then air can be introduced into the combustion chamber, but the swirl is lost and mixing with fuel vapor is insufficient
Solution Approach 1:
The invention removes the radial slots from the air inlet attachment peripheral wall, extracting the harmful feature that caused swirl loss. The air inlet attachment is redesigned without radial openings, forcing air to maintain axial flow and preserve swirl into the combustion chamber.
Solution Approach 2:
Instead of allowing air to flow radially outward through slots, the invention inverts the approach by designing the air inlet attachment to force axial flow. The air is directed straight through the attachment into the combustion chamber, reversing the conventional radial flow pattern to preserve turbulence and swirl.
2Object-generated harmful factors
If the air inlet attachment is designed to maintain swirl and turbulence for better mixing, then pollutant emissions are reduced, but the structural design becomes more complex
Solution Approach 1:
The invention simplifies the air inlet attachment by removing complex radial slot structures and peripheral wall openings. The design becomes simpler by eliminating the need for multiple air passage openings and radial flow paths, while still achieving effective mixing through axial flow and swirl preservation.
3Quantity of substance
If porous evaporator medium is provided on the peripheral wall to absorb and evaporate fuel, then fuel vapor is generated, but the air flow path becomes restricted and mixing is impaired
Solution Approach 1:
The porous evaporator medium is relocated from the peripheral wall to the bottom wall of the housing, creating a localized fuel vaporization zone. This positioning allows the evaporator medium to generate fuel vapor without obstructing the axial air flow path through the air inlet attachment, enabling both effective fuel evaporation and proper air-fuel mixing.
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 results in optimized mixing of air and fuel vapor, significantly reducing NOx emissions, allowing the evaporator burner to meet both existing vehicle heater and stricter building heating emission standards, achieving NOx values below 60 mg/kWh while maintaining low CO2 emissions.
Implementation Method 1
porous evaporator medium is provided on the inside of the peripheral wall of the housing, which absorbs liquid fuel and evaporates in the direction of the combustion chamber
Implementation Method 2
porous evaporator medium is provided on the inside of the peripheral wall of the housing, which absorbs liquid fuel
Implementation Method 3
a swirl device is provided upstream of the air inlet extension, which ensures that the air flowing into the air inlet extension already has a swirl that is essentially central to a longitudinal central axis of the housing
Implementation Method 4
there is only comparatively little eddying or turbulence, which also ensures suitable mixing with the air in the combustion chamber should cause existing fuel vapor
Data Source
Figure 1
Figure 2~4
AI summary
The assembly has a housing (14) exhibiting a base wall (18), where an air inlet projection (24) projects towards a housing interior (20) from the base wall. The air inlet projection exhibits a peripheral wall without air inlet openings and is opened at an air inlet end (36) that is distant from the base wall. A closure wall is attached at the peripheral wall of the air intake projection at the air inlet end, and the air inlet projection is opened in a region of the closure wall.