Cooling Fan Lip Guide for Recirculating Flow Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Cooling fan modules in motor vehicles suffer from reduced efficiency and increased noise due to recirculating flow and swirling motion at the fan blade tip region, which affects airflow separation and overall performance.
Innovation Solution
A cooling fan module design featuring a recirculating flow guiding device with guide vanes oriented radially around the fan impeller, an air gap between the fan ring and frame, and a lip portion that directs recirculating airflow into the guide vanes to remove swirl motion, enhancing airflow directionality and reducing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the fan impeller operates to generate airflow for cooling, then cooling performance is improved, but recirculating flow and swirl motion occur at the blade tip region causing airflow separation and reduced efficiency
Solution Approach 1:
The patent extracts and removes the harmful recirculating flow and swirl motion from the system by providing a dedicated flow control structure (the turned-in lip portion) that actively directs the recirculating airflow away from the blade tip region, preventing it from re-entering the fan and causing separation
Solution Approach 2:
The patent applies a local modification to the fan ring structure by turning in the leading end of the lip portion specifically at the region where it interacts with recirculating flow, creating a localized flow control feature that addresses the blade tip problem without affecting the overall fan operation
2Temperature
If the fan impeller rotates to remove heat from the engine, then cooling effectiveness is improved, but noise is generated due to airflow separation in the blade tip region
Solution Approach 1:
The patent converts the harmful recirculating flow that causes noise into a controlled flow pattern by using the turned-in lip portion to redirect it through the air gap, transforming a noise-generating phenomenon into a controlled airflow path that no longer causes blade tip separation and associated noise
3Productivity
If the pressure difference drives airflow through the fan, then cooling performance is improved, but recirculating flow forms through the running clearance between the frame and fan ring
Solution Approach 1:
The patent introduces an intermediary flow control structure (the turned-in lip portion acting as a guide) that mediates between the high-pressure downstream side and the low-pressure upstream side, directing the recirculating flow through a controlled path in the air gap rather than allowing it to create complex uncontrolled circulation patterns
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 solution improves fan efficiency and reduces noise by stabilizing airflow at the fan blade tip region, increasing fan pressure rise and efficiency across the operating range.
Implementation Method 1
a recirculating flow guiding device located on the upstream side of the frame and around the opening of the frame, wherein an air gap is provided between the fan ring and the frame, a recirculating flow from downstream side of the cooling fan module flowing through said air gap, and is turned by the leading end of the lip portion into the recirculating flow guiding device to remove swirl motion from the recirculating flow
Data Source
AI summary
A cooling fan module includes a frame, and a fan impeller having a plurality of fan impeller blades is located in an opening of the frame. The fan impeller blades are connected to a base portion of an outer fan ring. A lip portion of the outer fan ring extends from the base portion radially outward, and a leading end of the lip portion is turned in direction to the downstream side of the frame. A recirculating flow guiding device includes a plurality of guide vanes located on an upstream side of the frame and around the opening of the frame. An air gap is provided between the outer fan ring and the frame. A recirculating flow travels from downstream side of the cooling fan module through the air gap, and is turned by the leading end of the lip portion into the recirculating flow guiding device.