Contrarotating Vortex Nozzle for EGR Mixing in Non-Circular Ducts
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Solution Overview
Problem
Existing exhaust gas recirculation devices face challenges in achieving uniform mixing of exhaust gases with air in internal combustion engines, particularly in non-circular cross-section air inlet ducts and manifolds with flattened geometries, leading to inefficient energy use and potential wall heating issues.
Innovation Solution
A double tubular mixing nozzle system with a single exhaust gas carrying pipe creates contrarotating swirling vortexes that self-sustain within the air inlet duct and manifold, ensuring uniform distribution and minimizing energy loss, while maintaining a simple structure and manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single tubular mixing nozzle is used in circular cross-section ducts, then uniform mixing is achieved, but the solution becomes defective for oblong cross-section ducts and flattened manifolds
Solution Approach 1:
The single tubular mixing nozzle is divided into two separate tubular nozzles positioned side by side within the air inlet duct. Each nozzle independently creates a swirling vortex, and the two vortices interact to improve mixing uniformity across different duct geometries including oblong and flattened cross-sections.
Solution Approach 2:
The two tubular nozzles are positioned asymmetrically relative to the duct centerline, with each nozzle oriented to create contrarotating vortices. This asymmetric arrangement allows the vortices to interact in a way that maintains mixing uniformity in non-circular duct geometries where symmetric arrangements would fail.
2Manufacturing precision
If dual intake with two separate pipes is used, then mixing homogeneity improves, but device complexity and manufacturing cost increase
Solution Approach 1:
Two separate exhaust gas carrying pipes are merged into a single common pipe that supplies both tubular nozzles. This reduces the number of components, simplifies installation, and lowers manufacturing cost while the two nozzles still independently create the necessary contrarotating vortices for uniform mixing.
3Productivity
If swirling vortex is created in oblong cross-section ducts, then mixing occurs, but the vortex is rapidly destroyed and distribution uniformity deteriorates
Solution Approach 1:
The tubular nozzles are designed with specific curvature ratios (length-to-diameter ratio between 0.5 and 2.0) to optimize vortex formation and stability. The curved geometry of the nozzles creates controlled swirling flow that maintains vortex integrity longer in oblong and flattened duct geometries, improving both mixing efficiency and distribution uniformity.
4Manufacturing precision
If exhaust gases are introduced to create swirling vortex, then mixing with fresh air is enhanced, but kinetic energy is lost at vortex creation point
Solution Approach 1:
The system dynamically balances vortex strength and energy retention by optimizing the nozzle geometry and exhaust gas flow distribution. The contrarotating vortices interact to maintain rotational energy further downstream, reducing kinetic energy loss while achieving the necessary mixing homogeneity.
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 enhances the homogeneity of gas mixing, retains kinetic energy, and prevents wall contact, thus improving engine cylinder distribution and reducing manufacturing complexity.
Implementation Method 1
creating a swirling vortex in the mixing nozzle and in the downstream part of the inlet duct
Implementation Method 2
The mixing of the exhaust gases with the air is therefore far less effective and less uniform
Data Source
AI summary
A recirculation device includes an air intake duct (3) which is followed by a manifold (6), means for introducing recycled exhaust gases, for mixing same with the fresh air let in. This device is designed to inject the exhaust gases by forming two counter-rotating adjacent vortices (14, 15), owing to a twin tubular mixer nozzle (10, 11) in communication with a common exhaust gas supply duct, positioned tangentially with respect to the two nozzles, placed side by side. The two vortices (14, 15) are self-sustaining to the outlets (7) of the manifold (6). Such a recirculation device is applied, in particular, to an air intake duct (3) of oblong cross section and/or to a manifold (6) with a flattened inlet (5) and/or a flattened plenum (8), in particular for a motor vehicle engine.