Converging Liquid Reductant Injector Nozzle for SCR Atomization
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Solution Overview
Problem
Existing liquid reductant injector nozzles for SCR systems lack efficient atomization and repeatability due to straight sections that fail to accelerate the liquid and create unfavorable pressure gradients, leading to spray asymmetry and increased variability, which affects deNOx efficiency and causes solid deposit formation.
Innovation Solution
A liquid reductant injector nozzle with a converging section, comprising a hollow cylindrical static chamber and a frustoconical converging section connected to a sharp-edged discharge orifice, which converts pressure energy into kinetic energy for enhanced atomization and reduces variability, maintaining mechanical strength and preventing deposits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a straight section is used in the injector nozzle, then the structure is simple, but the liquid reductant is not efficiently atomized and spray symmetry deteriorates
Solution Approach 1:
The patent replaces the straight cylindrical section with a converging conical section, where the diameter gradually decreases from the upstream end to the downstream end. This curved/angled geometry accelerates the liquid reductant flow and improves atomization quality, resolving the contradiction between structural simplicity and spray precision.
2Device complexity
If a straight section is used in the injector nozzle, then the device complexity is low, but spray symmetry and repeatability deteriorate
Solution Approach 1:
The converging conical section creates a controlled pressure gradient that accelerates liquid flow uniformly, ensuring symmetric spray patterns and consistent atomization quality across multiple injection cycles, thereby improving reliability without significantly increasing device complexity.
3Manufacturing precision
If a converging section is added to accelerate liquid, then atomization improves, but device complexity increases
Solution Approach 1:
The converging conical section is integrated as a single continuous geometry within the nozzle body, accelerating liquid flow through its tapered shape to improve atomization. This design achieves enhanced spray quality while maintaining relatively simple manufacturing, as the conical section can be formed in a single machining or molding operation.
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 nozzle produces a well-atomized spray with high part-to-part and cycle-to-cycle repeatability, improving deNOx efficiency and durability, while minimizing solid deposit formation and maintaining mechanical strength under varying temperatures.
Implementation Method 1
converts pressure energy into kinetic energy for enhanced atomization
Implementation Method 2
introducing a liquid reductant into a stream of exhaust gases containing pollutants so as to produce a well-atomized spray
Data Source
AI summary
A liquid reductant injector nozzle includes a first portion defining a hollow cylindrical static chamber, in fluid communication with second portion defining a hollow frustoconical converging section, which is in turn in fluid communication with a sharp edged type discharge orifice. The hollow cylindrical static chamber is in reductant receiving communication with a reductant source, and has a first and second circular opening having equal diameters. The second circular opening is downstream of the first circular opening. The hollow frustoconical converging section is in reductant receiving communication with the hollow cylindrical static chamber via the second circular opening. Reductant received from the reductant source is discharged through the discharge orifice. A sidewall of the hollow cylindrical static chamber and a frustum side of the frustoconical converging section define an angle of convergence of the liquid reductant injector nozzle relative to a plane of the second circular opening.