Swirl Unit Reagent Mixer for Exhaust Gas Mixing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current exhaust aftertreatment systems face challenges in effectively reducing nitrous oxides (NOx) in exhaust gases due to inefficient mixing of reagents with exhaust gases, leading to incomplete chemical reactions and reduced effluent reduction efficiency.
Innovation Solution
A reagent mixer with a swirl unit and doser configuration that induces rotation of exhaust gases and reagent injection, enhancing mixing through a swirl chamber with inlet and outlet reactors, ensuring thorough interaction and increased transformation of NOx into molecular nitrogen and water vapor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a reagent is injected into exhaust gases without a swirl unit, then the device complexity is reduced, but the mixing efficiency between reagent and exhaust gases deteriorates
Solution Approach 1:
The patent employs a swirl unit with curved surfaces and spiral geometry to induce rotational motion in the exhaust gases. The curved geometry of the swirl unit creates centrifugal forces that enhance the mixing between reagent and exhaust gases, transforming the flow pattern from linear to rotational without adding complex mechanical components.
Solution Approach 2:
The invention utilizes fluid dynamic principles by injecting the reagent perpendicular to the exhaust gas flow and using the resulting pressure differentials and flow interactions to create swirling motion. The doser positioning and injection angle are optimized to leverage pneumatic forces for effective mixing without mechanical actuators.
2Speed
If exhaust gases flow directly through the mixer without swirling, then the flow velocity is maintained, but the transformation rate of NOx into molecular nitrogen deteriorates
Solution Approach 1:
The swirl unit's curved geometry extends the residence time of exhaust gases in the mixing zone by creating a spiral flow path. This increases the distance over which mixing occurs and allows more time for the chemical transformation of NOx, thereby improving productivity without reducing flow velocity.
Solution Approach 2:
The invention transitions the flow from one-dimensional linear movement to three-dimensional rotational flow. This dimensional change creates multiple mixing zones and enhances contact between reagent and exhaust gases, improving the transformation rate while preserving forward flow velocity through the outlet reactor.
3Device complexity
If the doser axis is aligned with the primary axis, then the injection system is simpler, but the reagent distribution uniformity in exhaust gases deteriorates
Solution Approach 1:
The patent deliberately positions the doser axis perpendicular to the primary exhaust gas flow axis, creating an asymmetric injection configuration. This asymmetric arrangement ensures that the reagent is injected across the flow rather than along it, promoting better distribution and mixing throughout the exhaust gas stream.
Solution Approach 2:
The swirl unit compensates for the perpendicular doser positioning by creating rotational flow that distributes the reagent uniformly. The curved flow paths ensure that reagent injected from the perpendicular doser is carried throughout the mixing chamber, achieving uniform distribution despite the non-aligned configuration.
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
The solution significantly increases the transformation rate of NOx into environmentally benign compounds, improving the efficiency of reagent mixing and reducing harmful emissions before exhaust gases are released into the atmosphere.
Implementation Method 1
The swirl unit is configured to rotate the mixture and to increase a transformation rate of NOx in the mixture into molecular nitrogen and water vapor by enhancing mixing of the reagent with the exhaust gases
Implementation Method 2
The inlet reactor provides a first flow passageway and a second flow passageway that direct the exhaust gases toward the injection point of the reagent and cause rotation of the exhaust gases in the swirl chamber
Implementation Method 3
The reagent combines with the exhaust gases to cause a chemical reaction and reduce effluents, such as nitrous oxides (NOx), in the exhaust gases before they are released into the atmosphere
Data Source
AI summary
An automotive exhaust aftertreatment system includes a reagent mixer. The reagent mixer includes a mixer body and doser that injects a reagent into the mixer body. The reagent mixer mixes an exhaust gases and the reagent prior to the exhaust gases being discharged from the reagent mixer.