Propeller Fan Rib Design to Reduce Air Backflow and Vortex Loss
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In propeller fan systems, air blown out is at risk of flowing back due to centrifugal force, reducing air blow efficiency, and the formation of Krmn vortices at the outer peripheral edge of static blades can further decrease efficiency.
Innovation Solution
The propeller fan features a rotary blade with a rib on its outer peripheral edge to guide air leeward and a static blade with a notch and chamfered corner to prevent vortex formation, while the fan housing is designed to convert dynamic pressure into static pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If air is blown by the propeller fan, then air flow is generated, but air may flow back due to centrifugal force reducing efficiency
Solution Approach 1:
A rib structure is added specifically at the outer peripheral edge portion of the rotary blade body where air backflow occurs. This localized structural modification guides the airflow along the pressure surface toward the leeward side, preventing backflow without affecting other parts of the blade
Solution Approach 2:
The rib acts as an intermediary structure between the pressure surface and the airflow. It mediates the airflow direction by providing a physical guide that directs air toward the leeward side, preventing the air from flowing back to the suction surface
2Productivity
If the outer peripheral surface of the rotary blade is formed to match the enclosing member, then the gap is narrowed, but manufacturing precision is required
Solution Approach 1:
The cylindrical outer peripheral surface configuration is applied specifically to the outer peripheral edge portion of the rotary blade body. This localized geometric feature enables the blade to match the inner peripheral surface of the enclosing member, narrowing the gap at the critical outer peripheral region where air backflow occurs
Solution Approach 2:
The outer peripheral surface of the rotary blade body is formed with a cylindrical curvature that corresponds to the inner peripheral surface of the enclosing member. This curved surface configuration allows the blade to fit smoothly within the enclosing member, minimizing the gap and preventing air leakage
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 reduces air backflow, enhances air blow efficiency, and minimizes the risk of Krmn vortices, leading to improved airflow and efficiency in propeller fan systems.
Implementation Method 1
centrifugal force generated by rotation of the propeller fan makes the air travel from an inner peripheral side of the rotary blade body toward an outer peripheral side
Implementation Method 2
a diffuser, which converts kinetic energy of air blown out of the propeller fan into pressure energy
Data Source
AI summary
A propeller fan includes a rotary blade hub driven in rotation about a rotation axis, and a rotary blade installed at an outer periphery of the rotary blade hub. The rotary blade includes a rotary blade body protruding from an outer peripheral surface of the rotary blade hub, and a rib formed on an outer peripheral edge portion of a pressure surface of the rotary blade body so as to extend along an outer peripheral edge of the rotary blade body.