Exhaust Mixer With Offset Vanes For SCR Mixing

The mixer is segmented into multiple functional zones: a Venturi body for primary mixing, a louver section for flow distribution, and offset vanes for secondary mixing. This segmentation allows each component to perform a specific mixing function, improving overall mixing uniformity while keeping individual components relatively simple in structure.

The Venturi body employs curved streamlines and a tapered geometry that transitions smoothly from inlet to outlet. This curvature design promotes uniform flow distribution and reduces turbulence, enhancing mixing efficiency without requiring complex mechanical moving parts.

The Venturi body utilizes the Venturi effect, a pneumatic principle where a tapered section accelerates fluid flow and creates a low-pressure zone that draws in and mixes the reductant. This passive pneumatic mixing achieves high mixing efficiency without mechanical components that would increase pressure drop.

The mixer changes flow parameters continuously through its length: the Venturi body increases velocity and decreases pressure to enhance reductant injection, while the expanding section downstream reduces velocity and increases pressure to maintain mixing. These parameter changes optimize mixing efficiency while managing pressure drop.

The vanes are intentionally positioned with their hubs offset from the body center axis, creating an asymmetric configuration. This asymmetry generates rotational flow patterns and enhances turbulence in the mixing zone, significantly improving mixing effectiveness compared to a symmetric centered arrangement.

The offset vane positioning introduces a rotational component to the flow in the radial dimension, transforming the primarily axial flow into a three-dimensional swirling flow pattern. This dimensional change enhances mixing by creating multiple flow paths and increasing contact between exhaust gas and reductant.