Flow-Separated Fan Structure for Rotating Machine Cooling
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Solution Overview
Problem
Current rotating electrical machine fan designs face inefficiencies due to airflow interactions, leading to vortices and inadequate cooling, particularly in the center of the machine, and often require complex structures or increased length.
Innovation Solution
A fan with a flow separator that extends partway through the fan blades, separating airflows from radially outward and inward directions, allowing a single set of fan blades to handle both airflows efficiently without increasing the fan's length, and using a flow separator with an annular vane configuration to direct and merge airflows effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional fan design is used with single inlet, then the structure is simple, but airflow from stator and rotor collide creating vortex and reducing fan efficiency
Solution Approach 1:
The fan inlet is segmented into two separate inlets: a first inlet positioned to receive airflow from the stator/frame airgap, and a second inlet positioned to receive airflow from the rotor/stator airgap. This segmentation prevents the collision of airflows that would otherwise create vortices, thereby improving fan efficiency while maintaining a relatively simple structure.
2Productivity
If multichannel fan with solid web separator is used, then airflow separation is achieved, but the fan length increases and structure becomes complicated
Solution Approach 1:
Instead of using a solid web separator that extends axially through the fan (adding length), the invention separates airflows spatially by providing distinct inlet positions for stator airflow and rotor airflow. This dimensional repositioning of inlets allows airflow separation without increasing fan length or requiring complex internal separators.
3Ease of manufacture
If fan inlet is positioned at midpoint of stator end windings, then mounting is simplified, but stator airflow dominates and center cooling is insufficient
Solution Approach 1:
The fan provides different airflow sources for different regions: the first inlet receives stator airflow that cools the stator and end windings, while the second inlet receives rotor airflow that is directed to provide enhanced cooling at the center of the machine where it is most needed. This local differentiation of airflow sources improves center cooling effectiveness.
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 design improves airflow efficiency by reducing vortex formation and enhancing cooling at the machine's center, while maintaining a simple construction and avoiding lengthening of the fan, thus achieving better thermal performance.
Implementation Method 1
a flow separator for separating a first airflow entering the fan from a radially outwards part of the machine and second airflow entering the fan from a radially inwards part of the machine
Implementation Method 2
The fan blades are preferably centrifugal blades, and are preferably arranged to dispel air radially
Data Source
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AI summary
A fan for a rotating electrical machine is disclosed. The fan (14) comprises a plurality of fan blades (16) and a flow separator (24) for separating a first airflow entering the fan from a radially outwards part of the machine and second airflow entering the fan from a radially inwards part of the machine. The flow separator (24) extends partway through the fan in a direction of airflow. This may help to improve the efficiency of the fan using a relatively simple construction and without adding to its length.