Coanda Ring Cooling Fan Leakage Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Cooling fans in motor vehicles experience efficiency losses due to air leakage upstream past fan blades, which reduces the effectiveness of the airflow and increases static pressure differentials, leading to wasted energy.
Innovation Solution
A Coanda ring is positioned between the fan and stator vanes, utilizing the Coanda Effect to entrain high-pressure air and reduce leakage by ensuring the fan exhaust adheres to the duct walls, thereby preventing reverse flow and increasing the cross-sectional area of the exhaust.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If fan blades move air downstream to cool the radiator, then cooling function is achieved, but air leaks upstream past the fan blades causing efficiency loss
Solution Approach 1:
A Coanda ring is introduced as an intermediary component between the fan blades and stator vanes. This ring utilizes the Coanda effect to guide and attach the airflow along its curved surface, preventing the air from leaking upstream past the fan blades while maintaining the downstream cooling flow.
Solution Approach 2:
The patent changes the flow direction and attachment characteristics of the air stream by introducing the Coanda ring with specific curvature and angle parameters. The ring is positioned at a specific angle relative to the fan axis and has optimized dimensions to maximize the Coanda effect, thereby controlling the airflow path and preventing leakage.
2Productivity
If static pressure differential is increased to improve airflow, then cooling effectiveness improves, but leakage flow increases
Solution Approach 1:
The Coanda ring serves as a mediator that allows the system to maintain high static pressure differential for improved airflow output while preventing the associated leakage. The ring's curved surface guides the high-pressure air along the downstream path, using the Coanda effect to attach the flow and prevent it from reversing and leaking upstream.
3Loss of energy
If Coanda ring is added to reduce leakage, then fan efficiency increases, but device complexity increases
Solution Approach 1:
The Coanda ring is implemented as a relatively simple annular component with a curved surface, resembling a flexible shell structure. This simple geometric form adds minimal complexity to the overall fan assembly while effectively utilizing the Coanda effect to control airflow and reduce 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
The implementation of the Coanda ring increases fan efficiency by at least three percent, reduces flow reversal, and enhances airflow output by maintaining attached flow along the ring, even in the presence of downstream obstructions, thereby improving cooling performance.
Implementation Method 1
Exhaust of the fan adheres to the walls of the duct because of the Coanda Effect, thereby reducing tendencies of the exhaust to reverse direction and leak upstream, past the tips of the fan blades.
Data Source
Figure 1~2D
Figure 3
Figure 4~5
AI summary
A cooling fan for an engine in a vehicle. Ordinarily, a fan rotates within a shroud, which surrounds the fan. Leakage can occur between the tips of the fan blades and the shroud, wherein fan exhaust moves forward, and then passes through the fan again. The invention reduces leakage by placing a surface downstream of the fan. The surface employs the Coanda Effect, to urge fan exhaust to continue in the downstream direction, and not move forward as leakage air.