Centrifugal Impeller Blade Geometry for Pressure Loss Reduction
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Solution Overview
Problem
Electric blowers used in vacuum cleaners and hand dryers face inefficiencies due to increased pressure loss on the large air volume side when intermediate blades are used to reduce size and weight, leading to reduced performance.
Innovation Solution
The design incorporates a centrifugal impeller with a hub and rotor blades, where the second rotor blade's inner circumferential edge is configured to maintain a larger air path area, reducing pressure loss by positioning the first portion closer to the outer circumferential portion, thus minimizing the area reduction between blades on the inner side.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If intermediate blades are added to the centrifugal impeller to improve air flow and efficiency on the small air volume side, then efficiency on the small air volume side is improved, but the area of the air path between the blades is reduced on the large air volume side, resulting in increased pressure loss and reduced efficiency
Solution Approach 1:
The inner circumferential edge of the intermediate blade is designed with different curvature radii at different locations: a first curvature radius at the front end, a second curvature radius at the rear end, and a third curvature radius at the intermediate portion. This local variation in geometric properties allows the blade to maintain optimal air flow characteristics across different operating conditions, resolving the contradiction between small and large air volume side performance
Solution Approach 2:
The invention changes the geometric parameters of the intermediate blade's inner circumferential edge by introducing multiple curvature radii with specific relationships (second < first and third). This parameter optimization enables the blade to adapt to varying air volumes, improving efficiency on the small air volume side while reducing pressure loss on the large air volume side
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 enhances efficiency and reduces pressure loss on the large air volume side, resulting in a highly efficient electric blower with reduced noise and extended operational life.
Implementation Method 1
a centrifugal impeller, an electric motor unit, and a fan cover. The centrifugal impeller includes a hub and a plurality of rotor blades. The electric motor unit is configured to rotate the centrifugal impeller.
Data Source
AI summary
Provided is an electric blower configured to include a centrifugal impeller provided with an intermediate blade, which reduces pressure loss inside an air path on a large air volume side and achieves high efficiency. In the electric blower, a first rotor blade and a second rotor blade each include an inner circumferential edge facing a central portion of a hub and connecting an upper edge and a lower edge. The inner circumferential edge of the second rotor blade includes a first portion connected to the lower edge, a second portion connected to the upper edge, and a third portion. The third portion is located between the first portion and the second portion. Among the first portion, the second portion, and the third portion, the first portion is located closest to an outer circumferential portion of the hub in a direction along a surface portion.