Radial Fan Diffuser Plate Curved Overflow Edge
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Solution Overview
Problem
Radial fans, particularly in vacuum cleaners, face challenges in achieving high aerodynamic efficiency while minimizing sound power levels.
Innovation Solution
The design incorporates a centrifugal fan with an impeller having obliquely curved blades that generate a radially outward air flow, which is deflected by a non-rotatable diffuser plate with strategically angled edge sections to guide the air flow axially, reducing noise and enhancing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the air flow is deflected radially outward through the impeller, then the volume flow is increased, but the sound power level increases due to flow separation at the diffuser plate edge
Solution Approach 1:
The diffuser plate edge is designed with a curved overflow edge instead of a sharp edge, featuring a radius of curvature that smoothly guides the air flow from radial to axial direction. This curvature eliminates flow separation and reduces turbulence-induced noise while maintaining high volume flow through the diffuser plate.
2Device complexity
If a sharp edge is used at the diffuser plate for flow direction change, then the structural simplicity is maintained, but flow separation occurs reducing aerodynamic efficiency
Solution Approach 1:
The overflow edge of the diffuser plate is formed with a continuous curved surface that smoothly transitions the air flow from radial to axial direction. This curved geometry eliminates flow separation and turbulence, significantly improving aerodynamic efficiency while adding minimal structural complexity to the diffuser plate design.
3Volume of moving object
If the diffuser plate openings are positioned close to the impeller periphery, then the compact design is achieved, but flow separation and noise increase due to the sharp edge effect
Solution Approach 1:
The diffuser plate openings are positioned close to the impeller periphery to achieve compact design, and the overflow edges of these openings are rounded with a specific radius of curvature. This curved edge design eliminates flow separation at the sharp edges, reducing turbulence and noise generation while maintaining the compact overall dimensions of the radial fan.
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 configuration results in a high aerodynamic efficiency with a low sound power level, allowing for improved suction performance and reduced noise in vacuum cleaners.
Implementation Method 1
an aerodynamic device, which includes a radial impeller... the impeller has a plurality of blades arranged to produce a radially outward flow of air
Implementation Method 2
the outer edge of the diffuser plate has at least one edge section against which the flow occurs and at least one edge section over which the flow occurs... the at least one edge section over which the flow occurs has a partial section which is designed as a circular arc
Data Source
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AI summary
A radial blower, particularly for a vacuum cleaner, comprises an impeller (2) rotatable about a rotational axis (9) and driven by a motor, the impeller having a plurality of blades (7) for generating an airflow directed at least partially radially outwards, and a stationary guide vane (3) comprising a diffuser plate (48) arranged perpendicular to the rotational axis (9) adjacent to the impeller (2), an annular wall (14) radially surrounding the diffuser plate, and a hood (21) at least partially enclosing the impeller (2), wherein a continuous annular space (23) radially surrounding the impeller (2) is formed between the hood (21), the impeller (2), and the diffuser plate (48), and wherein a plurality of openings (50) are formed between an outer edge of the diffuser plate (48) and the annular wall (14), allowing air to pass from the annular space (23) to the side of the diffuser plate opposite the impeller (2). (48) enable,wherein the outer edge of the diffuser plate (48) in the area of each opening (50) has at least one flow-inside edge section (34) and at least one flow-overside edge section (49), and wherein the at least one flow-overside edge section (49) has a subsection (46) which is designed as a circular arc whose center lies on the axis of rotation (9). This creates a radial fan which enables a higher aerodynamic efficiency and/or a reduction in the overall sound power level.