Annular Air Intake Structure for Reducing Flow Noise
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Solution Overview
Problem
Conventional air intakes in motor vehicle air-conditioning systems generate undesirable noise due to eddy formation during high flow rates, which existing solutions fail to effectively address without significant structural modifications or noise deflection.
Innovation Solution
An air intake design featuring an annular structure with an opening that allows fluid to pass through and around it, oriented substantially parallel to the outlet port area, which minimizes eddy formation and noise without deflecting the flow direction, using radial struts to stabilize the structure and maintain minimal pressure differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high flow rates are present in air intakes, then productivity is improved, but flow-related noise increases due to eddy formation
Solution Approach 1:
The patent introduces an intermediate structure (the annular structure with opening) in the air intake that acts as a mediator to disrupt eddy formation. This structure allows flow to pass through and around it, preventing the formation of vortices that cause noise while maintaining high flow rates.
Solution Approach 2:
The patent changes geometric parameters of the air intake by introducing a structure with specific dimensional ratios (span 0.35-0.5 times inlet port span, clear cross-section 0.1-0.3 times outlet port cross-section). These parameter changes optimize flow characteristics to reduce noise while preserving productivity.
2Object-generated harmful factors
If radial baffles are used to counter eddy formation, then flow noise is reduced, but device complexity increases and flow direction must be greatly deflected
Solution Approach 1:
Instead of using complex radial baffles, the patent employs a segmented annular structure with a central opening. This segmentation allows flow to pass through the opening while the annular portion disrupts eddies, achieving noise reduction with simpler geometry and less structural complexity.
Solution Approach 2:
Rather than using solid radial baffles that block and deflect flow, the patent inverts the approach by using an annular structure with a large central opening. This allows flow to pass through rather than around, reducing deflection requirements and structural complexity while maintaining noise reduction effectiveness.
3Object-generated harmful factors
If a structure is added to reduce noise, then flow noise is reduced, but pressure differences increase
Solution Approach 1:
The patent optimizes the clear cross-section ratio (0.1-0.3 times outlet port cross-section) to balance noise reduction with pressure loss minimization. This parameter optimization ensures sufficient opening area to maintain pressure while the annular structure provides noise reduction.
Solution Approach 2:
The annular structure provides partial noise reduction through the opening and partial through flow around the annulus, achieving effective noise control without completely blocking flow paths, thereby minimizing pressure differences.
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
This design effectively reduces noise by preventing eddy formation and maintaining even flow, with noise reduction achieved through specific geometric ratios and configurations, such as a span of 0.35 to 0.5 times the inlet port area span and a clear cross-section of 0.1 to 0.3 times the outlet port area cross-section.
Implementation Method 1
high flow rates may be present in air intakes, which may result in undesirable noise generation in certain applications, in particular if so-called eddies arise
Data Source
AI summary
An air intake with at least one inlet port area and one outlet port area, in which there is arranged at least one structure which may be flowed through and around, comprises an opening and modifies the clear cross-section only slightly, in particular serving as a fresh air/recirculated air housing for a motor vehicle heating, ventilation and/or air-conditioning system.