Exhaust Static Mixer Vortex Blades Pressure Loss
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Solution Overview
Problem
Existing static mixers for exhaust gas ducts of internal combustion engines face challenges in achieving efficient mixing while minimizing pressure increases and condensate formation, leading to complex and costly designs.
Innovation Solution
A static mixer with a frustoconical hollow metal body featuring radial openings and concave blades that promote a vortex-like flow, allowing gases to enter and exit through a single axial opening, reducing the need for additional structures and minimizing condensate formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a static mixer with blades and annular frame is used to promote mixing of exhaust gases with reducing agent, then mixing effectiveness is improved, but pressure increase in the exhaust system worsens
Solution Approach 1:
The mixer body is divided into multiple axial sections with different blade configurations. Each section has blades with specific orientations and densities optimized for local mixing requirements, allowing gradual mixing progression while reducing overall flow resistance compared to a single dense blade array.
Solution Approach 2:
Different sections of the mixer have locally optimized blade characteristics - upstream sections have blades configured for initial mixing and downstream sections have blades optimized for final homogenization. The blade density, orientation, and angle vary axially to match the local flow conditions and mixing requirements at each position.
2Reliability
If mixer surfaces are provided to promote mixing, then mixing capability is improved, but condensate formation on surfaces worsens
Solution Approach 1:
The blades are designed with curved and rounded surfaces instead of flat planar surfaces. The convex and concave surfaces create smooth flow paths that reduce flow separation and minimize dead zones where condensate could accumulate. The frustoconical shape of the mixer body also contributes to streamlined flow.
Solution Approach 2:
The design accepts that some condensate formation is inevitable but converts this potential harm into a benefit by designing blades that guide condensate flow toward the outlet. The curved blade surfaces create flow patterns that prevent condensate accumulation in harmful locations while maintaining mixing effectiveness.
3Reliability
If complex blade arrangements are used to achieve best mixing, then mixing performance is improved, but manufacturing complexity and cost worsen
Solution Approach 1:
The mixer design uses a limited set of standardized blade profiles and configurations that can be manufactured using the same tooling and processes for all sections. The blades follow systematic patterns of orientation and arrangement that simplify manufacturing while still providing effective mixing through the segmented axial design.
Solution Approach 2:
Multiple blade functions are combined into integrated blade structures that perform both mixing and condensate management simultaneously. The convex and concave surfaces of each blade serve dual purposes: creating turbulence for mixing and guiding condensate flow, reducing the need for separate components.
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 mixer achieves efficient gas mixing with reduced pressure increase and condensate formation, enabling simpler and cost-effective manufacturing, and versatility in various exhaust systems, including those using selective catalytic reduction (SCR) technology.
Implementation Method 1
concave blades that promote a vortex-like flow
Implementation Method 2
The static mixer promotes mixing of the gases with the reducing agent, generally thanks to the increase of the turbulence phenomenon within the exhaust gas flow
Implementation Method 3
causing the reducing agent introduced into the exhaust system to be evaporated as much as possible
Data Source
Figure 1
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Figure 3
AI summary
Static mixer (11) for exhaust gas ducts of internal combustion engines, comprising an elongated hollow metal body (13) having a shape which, relative to a symmetry axis (S), substantially corresponds to a solid of revolution defining at its inside a cavity (15), in which opposite bases (17,19) are defined, at least one of which is provided with an axial opening, and a closed lateral wall (23) is defined connected to the opposite bases (17,19) and having at least one radial opening (25) over which a concave blade (27) is arranged extending radially outward of the lateral wall (23) of the mixer body from a portion of the peripheral edge (29) of the radial opening (25) and surrounding a portion of the radial opening (25) so as to define, in a first angular direction relative to the symmetry axis, a corresponding concave screen or spoon (31) and, in a second, opposite direction, a mouth (33) intended for the passage of gases and located substantially in front of the concave screen or spoon (31).