Ventilator Inlet Flow Rectifier for Rotary Noise and Pressure Loss
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Solution Overview
Problem
Existing fan arrangements fail to adequately reduce low-frequency noise, particularly rotary tones, and minimize pressure loss, as they either do not sufficiently address turbulence in the inflow or result in high pressure loss due to their design.
Innovation Solution
A lattice structure with intersecting lattice bars forming a geometric body, such as a truncated cone, encloses the flow inlet opening with a central, web-free inflow opening that has a smaller area than the inlet opening, reducing turbulence and pressure loss by preventing fluctuations in velocity perpendicular to the main flow direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a flow straightener with star-shaped baffles is used, then the structure is simple, but the low-frequency noise and rotary tones are not sufficiently reduced
Solution Approach 1:
The flow straightener is divided into multiple functional zones: an outer annular baffle structure for general flow guidance and an inner lattice structure with multiple openings for targeted turbulence reduction. This segmentation allows each zone to address specific noise sources while maintaining overall structural simplicity.
Solution Approach 2:
Different regions of the flow straightener have different structural properties: the outer region uses simple star-shaped baffles for basic flow direction, while the inner region employs a complex lattice structure with multiple openings specifically positioned to reduce rotary tones. This local differentiation optimizes noise reduction effectiveness without unnecessarily complicating the entire structure.
2Stability of the object's composition
If a flow straightener with many annular and axial webs is used, then the flow straightening effect is improved, but the pressure loss increases significantly
Solution Approach 1:
The web structure is segmented into discrete lattice elements with openings rather than continuous solid webs. This segmentation allows the flow to pass through multiple pathways, reducing the cumulative pressure loss while still providing sufficient flow straightening through the distributed lattice structure.
Solution Approach 2:
The lattice structure functions as a porous flow control element, where the openings between lattice bars allow fluid passage while the bars themselves provide flow guidance. This porous approach reduces pressure loss compared to solid web structures while maintaining flow straightening effectiveness.
3Stability of the object's composition
If the inflow opening area is reduced by the bar structure, then the turbulence is reduced, but the flow capacity may be limited
Solution Approach 1:
The inflow opening is segmented into multiple smaller openings within the lattice structure rather than a single large opening. This segmentation reduces turbulence at each local point while the collective area of all openings maintains sufficient overall flow capacity.
Solution Approach 2:
The lattice structure extends the flow control in the axial dimension by creating a three-dimensional pattern of openings and bars. This dimensional approach allows turbulence reduction through extended flow path guidance while maintaining flow capacity through the vertical stacking of opening areas.
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 design significantly reduces rotary noise and rated sound power levels while maintaining efficiency, achieving noise advantages comparable to undisturbed inflow conditions with minimal deterioration in performance.
Implementation Method 1
The walls formed by the lattice webs prevent fluctuations in velocity perpendicular to the main direction of flow
Data Source
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AI summary
The device has a guide inlet opening that is configured on a suction side at an axial height in front of a flow inlet opening (15) of a bar structure and formed with opening surface smaller than flow inlet opening. The bar structure is formed by a grid structure consisting of intersecting grid bars with the grid openings enclosed by grid bars. The grid bars are provided such that the ratio of height to thickness of grid bars is greater than 5. The grid openings are provided such that the ratio of a peripheral grid width to radial width of openings lies in a range between 1/ 3-3.