Propeller Fan Inner Blade Segmentation for Airflow Balance
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Solution Overview
Problem
The existing propeller fans in outdoor air conditioners face a wind speed difference between the outer and inner peripheral parts of the blade, leading to reduced air volume due to interference from the inner peripheral air current, causing strange sounds and decreased airflow efficiency.
Innovation Solution
A propeller fan design featuring a hub with blades that include an inner peripheral blade with projecting blade elements and specific angle configurations, such as the first and second blade elements, which increase wind speed at the inner peripheral part by guiding air flow through optimized blade angles and openings, reducing wind speed disparities and enhancing airflow efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the diameter and rotation speed of the propeller fan are increased to increase air volume, then the wind speed at the outer peripheral part is increased, but the wind speed difference between the outer and inner peripheral parts is further increased causing air current interference and strange sounds
Solution Approach 1:
The patent applies local quality by forming an inner peripheral blade with multiple blade elements at the inner peripheral part of the blade, where each blade element has a specific blade angle range (15-45 degrees). This local structural modification targets specifically the inner peripheral region to generate additional wind speed and air current, without changing the overall fan diameter or rotation speed, thereby resolving the wind speed difference problem while maintaining air volume
Solution Approach 2:
The inner peripheral blade is segmented into multiple blade elements arranged side by side in the rotation direction. This segmentation allows each element to independently contribute to air flow generation, creating a distributed effect that increases wind speed at the inner peripheral part without causing concentrated air current interference, thus resolving the contradiction between air volume and wind speed difference
2Productivity
If the rotation speed is increased to compensate for low wind speed at the inner peripheral part, then air volume is improved, but energy consumption increases
Solution Approach 1:
Instead of increasing rotation speed globally, the patent applies local quality by adding blade elements specifically at the inner peripheral part where wind speed is low. This localized modification generates additional air current only where needed, improving air volume without requiring increased rotation speed, thereby avoiding additional energy consumption
Solution Approach 2:
The patent changes the geometric parameters of the blade by introducing blade elements with specific blade angles (15-45 degrees) at the inner peripheral part. This parameter change optimizes the air flow generation efficiency at the low wind speed region, achieving improved air volume through geometric optimization rather than increasing rotation speed, thus reducing energy consumption
3Productivity
If the wind speed at the outer peripheral part is increased to compensate for inner peripheral deficiency, then air volume is improved, but air current from the inner peripheral part interferes with the outer peripheral air current causing reduced air volume
Solution Approach 1:
The inner peripheral blade is divided into multiple segmented blade elements arranged side by side. This segmentation creates multiple small-scale air currents that collectively contribute to overall air flow without creating a single strong interfering current. The segmented structure distributes the air generation effect, preventing interference with the outer peripheral air current while maintaining stable air flow composition
Solution Approach 2:
The blade elements are designed with curved surfaces and specific blade angles to optimize air flow patterns. The curved geometry guides air flow smoothly from the inner peripheral part toward the outer peripheral part, reducing turbulence and interference with the outer air current, thereby maintaining stable air current composition while improving air volume
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 effectively increases wind speed and air volume at the inner peripheral part, improving airflow efficiency and reducing energy consumption by minimizing the need for higher rotation speeds, thus enhancing the energy-saving performance of air conditioners.
Implementation Method 1
an inner peripheral blade, which extends from the side surface of the hub toward the outer edge side, is formed on a positive pressure surface of the blade surface part at the inner peripheral part of each of the blades, the inner peripheral blade includes a plurality of blade elements that project from the positive pressure surface of the blade surface part toward a positive pressure side
Implementation Method 2
The wind speed at the inner peripheral part is lower than that at the outer peripheral part of the blade, so that wind generated at the inner peripheral part flows to the outer peripheral part by centrifugal force to disturb flow of wind generated at the outer peripheral part
Data Source
AI summary
When an apex of a first blade element projecting from the positive pressure surface is A, a distance from the center axis to the apex A is r, and a point having the distance r from the center axis on a front edge in the rotation direction of the first blade element is B, the first blade element among the blade elements that is arranged on a front edge side in the rotation direction of the blade, is formed to have a blade angle equal to or larger than a predetermined first angle and equal to or smaller than a second angle that is larger than the first angle, the blade angle being formed by a direction along a chord of the first blade element along a direction that connects the apex A with the point B, and a plane orthogonal to the center axis.