Axial Stirring Impeller Blade Angles Reduce Power
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Solution Overview
Problem
Conventional stirring impellers require high power due to inefficient blade designs, particularly in the positional relationship of blades to the central axis of rotation and the shapes of blade edges, which leads to increased torque and operational costs.
Innovation Solution
The design features blades with specific inclination angles (20° to 40°) and tapered portions (30° to 50° tip angles) to reduce resistance, incorporating flat surfaces and curved contours to minimize phase differences and pressure resistance, and optional rectifiers for further power reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional stirring impeller blade designs are used, then the stirring function is provided, but high power is required due to increased torque
Solution Approach 1:
The patent applies parameter changes by optimizing the inclination angle of blade front portions (20° to 40°) and the tip angle of tapered portions (30° to 50°). These specific angular parameters reduce the resistance received from the stirring object, thereby decreasing the torque and power required for stirring operations.
Solution Approach 2:
The patent incorporates curved contours coupling the front end edge and outer end edge of blades, replacing conventional straight-edged blade designs. This curvature creates a phase difference in the timing at which the blade contacts the stirring object during rotation, reducing rotational resistance and power consumption.
2Power
If blade inclination angles and tapered portions are optimized, then resistance from stirring object is reduced, but blade shape complexity increases
Solution Approach 1:
The patent applies local quality by providing tapered portions specifically at the front end edges of blades where the inclination angles are set to 20° to 40°. The flat surfaces are located between front and back surfaces at these tapered portions. This localized geometric modification reduces resistance without requiring complete redesign of the entire blade structure, balancing performance improvement with manufacturing feasibility.
3Power
If flat surfaces are added between front and back surfaces of blades, then flow separation occurs and negative pressure increase is suppressed, but manufacturing complexity increases
Solution Approach 1:
The patent incorporates curved contours coupling the front end edge and outer end edge of blades, replacing conventional straight-edged blade designs. This curvature creates a phase difference in the timing at which the blade contacts the stirring object during rotation, reducing rotational resistance and power consumption.
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
An object of the present invention is to provide a stirring impeller and a stirring device capable of reducing power required for stirring. Provided are an axial stirring impeller 1 including a plurality of blades 3 arranged at intervals in a rotational direction with reference to the central axis of rotation, and a stirring device including the stirring impeller 1. Each of the plurality of blades 3 has a front portion with reference to at least the rotational direction R inclined to a plane orthogonal to the central axis of rotation in a cross section in the rotational direction R at an angle θ1 of 20° to 40° toward a front end edge 3a, and each of the plurality of blades 3 includes a tapered portion 31 tapered to have a tip angle of 30° to 50° in the cross section in the rotational direction R, on the front end edge 3a with reference to the rotational direction R.