Rotating Electrical Machine Cooler Flow Resistance Optimization
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Solution Overview
Problem
Conventional rotating electrical machines face challenges in downsizing their coolers without compromising cooling performance, as increasing the flow cross-sectional area to reduce pressure loss leads to larger machine sizes.
Innovation Solution
The cooler's flow resistance is optimized to fall within a specific range (0.15 < Ra/Rm < P0/P1), allowing for downsizing while maintaining cooling performance by adjusting the pressure loss and flow resistance ratios, and reducing the cooler's height without significantly increasing flow resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the flow cross-sectional area of the cooler is increased to reduce pressure loss, then the cooling performance is improved, but the size of the cooler and rotating electrical machine increases
Solution Approach 1:
The invention changes the flow resistance parameter of the cooler to an optimal value that balances pressure loss reduction with size constraints. By optimizing the flow resistance rather than simply increasing cross-sectional area, the patent achieves reduced pressure loss without proportionally increasing cooler dimensions
Solution Approach 2:
The invention introduces adjustability in the cooler's flow resistance characteristics, allowing the system to adapt to different operating conditions. This dynamic optimization enables the cooler to maintain efficient performance across varying loads without requiring a larger design capacity
2Loss of energy
If the pitch of the tubes in the tube bundle is increased to reduce flow resistance, then the pressure loss is reduced and cooling performance is enhanced, but the size of the cooler increases
Solution Approach 1:
The invention optimizes the tube pitch parameter to achieve the best balance between pressure loss reduction and cooler compactness. Rather than maximizing tube pitch to minimize resistance, the patent finds an optimal value that provides sufficient cooling performance while maintaining a compact footprint
3Volume of stationary object
If the cooler is downsized to reduce the size and weight of the rotating electrical machine, then the installation space and production costs are reduced, but the pressure loss increases and cooling performance degrades
Solution Approach 1:
The invention optimizes the cooler's flow resistance parameter to a specific value that enables downsizing without excessive pressure loss penalty. This optimized parameter allows the cooler to be more compact while maintaining acceptable cooling performance
Solution Approach 2:
The invention creates a cooler design that can adapt to size constraints through optimized flow resistance characteristics, allowing the system to achieve compact dimensions while maintaining effective cooling across operating conditions
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 approach enables a reduction in the size and weight of the rotating electrical machine without degrading cooling performance, reducing production costs, and minimizing installation space requirements.
Implementation Method 1
When the internal air passes through between the tubes of the tube bundle in the cooler, the internal air exchanges heat with the external air via the walls of the tubes, whereby the internal air is cooled.
Implementation Method 2
the internal air exchanges heat with the external air via the walls of the tubes
Implementation Method 3
a fan configured to circulate a coolant for cooling the stator and the rotor
Data Source
AI summary
A rotating electrical machine includes a rotating electrical machine body including a stator, a rotor, a fan configured to circulate a coolant for cooling the stator and the rotor, and a casing containing the stator, the rotor and the fan; and a cooler connected to the rotating electrical machine body. The coolant flows from the machine body into the cooler. The cooler cools the coolant. The coolant flows out of the cooler into the machine body. The cooler has a flow resistance Ra satisfying a relation 0.15<(Ra/Rm)<(P0/P1), wherein Ra is a flow resistance of the coolant in the cooler, Rm is a flow resistance of the coolant in the rotating electrical machine body, P0 is a shutoff pressure of the fan, and P1 is a pressure at an operating point of the fan when the flow resistance Ra of the cooler is assumed to be zero.