Curved-Fin Rotor Cooling for Low-Loss Electromagnetic Retarders
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Solution Overview
Problem
Existing rotors in electromagnetic retarders and generators suffer from deformation due to heat and have high aerodynamic losses, leading to inefficient cooling and performance degradation.
Innovation Solution
The rotor design incorporates curved cooling fins with specific curvature ratios and orientations to enhance air intake and evacuation, reducing friction and aerodynamic losses, and includes a crown structure to promote air access and evacuation through cooling channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the rotor uses a smooth or finned cylindrical body design, then the manufacturing is simple, but the cooling efficiency is insufficient causing rotor deformation after heavy use
Solution Approach 1:
The cooling fins are segmented into multiple rows (first row, second row, third row, fourth row) with different orientations and curvature directions. This segmentation allows each row to perform specific cooling functions, with forward-curving fins capturing incoming air and backward-curving fins evacuating hot air, thereby significantly improving cooling efficiency and preventing rotor deformation.
Solution Approach 2:
The cooling fins are designed with specific curvature radii and orientation angles rather than being straight. The first cooling fins have a forward curvature with a specific radius to capture incoming air, while the second cooling fins have a backward curvature to evacuate hot air. This curvature design optimizes air flow patterns and enhances cooling efficiency.
2Temperature
If the rotor has heavily ventilated cooling fins, then cooling efficiency improves, but aerodynamic losses increase
Solution Approach 1:
Different rows of cooling fins have different local qualities - the first row has forward-curving fins optimized for air intake, while the second row has backward-curving fins optimized for air evacuation. This local differentiation allows each region to perform its specific function efficiently, improving overall cooling while minimizing unnecessary aerodynamic drag from uniform fin designs.
Solution Approach 2:
The cooling fin design uses asymmetric curvature directions - forward curvature for intake fins and backward curvature for evacuation fins. This asymmetry creates optimized air flow paths that reduce turbulence and aerodynamic losses compared to symmetric or straight fin designs, while maintaining effective cooling.
3Temperature
If the cooling fins are arranged in single rows, then the structure is simple, but the cooling coverage is insufficient
Solution Approach 1:
The cooling fins are divided into four rows arranged around the cylindrical body, with each row serving specific cooling zones. The first and third rows have forward-curving fins for air intake, while the second and fourth rows have backward-curving fins for air evacuation. This segmentation provides comprehensive cooling coverage across the entire rotor surface.
Solution Approach 2:
The cooling fins are arranged in multiple rows around the cylindrical body, transitioning from a single-plane arrangement to a three-dimensional distributed arrangement. This multi-dimensional configuration ensures that cooling air can access and evacuate heat from all regions of the rotor, significantly improving cooling coverage.
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 design effectively prevents deformation and reduces aerodynamic losses, improving cooling efficiency and maintaining rotor performance over time.
Implementation Method 1
a plurality of first cooling fins arranged on the peripheral face of the cylindrical body, the first cooling fins being arranged in a first row extending along the first edge, the first cooling fins being curved and having a concavity facing forward considering the direction of rotation of the rotor, a plurality of second cooling fins arranged on the peripheral face of the cylindrical body, the second cooling fins being arranged in a second row extending parallel to the first row, the second cooling fins being curved and having a concavity facing backward considering the direction of rotation of the rotor
Implementation Method 2
the shape and arrangement of the second cooling fins allows friction between the air flows and the fins to be reduced and aerodynamic losses to be reduced
Implementation Method 3
the crown extends only above a central portion of the peripheral face, a portion of the first cooling fins and a portion of the second cooling fins being open to the outside. Advantageously, the opening above the inlet of the cooling channels promotes air access to the cooling channels and the opening above the outlet of the cooling channels promotes air evacuation.
Data Source
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AI summary
The invention relates to a rotor (2) of a rotating electrical machine, the rotor comprising: - a cylindrical body (6) comprising a peripheral face (30), a lateral connection face (28); the peripheral face comprising a first edge (34) adjacent to the lateral connection face; - an inner ring (4) coaxial with the cylindrical body; - fixing arms (8) connected to the inner ring and to the lateral connection face of the cylindrical body, - first cooling fins (38) arranged on the peripheral face, the first cooling fins extending along the first edge, the first cooling fins being curved and having a concavity facing forward, - second cooling fins (39) arranged on the peripheral face, the second cooling fins being curved and having a concavity facing rearward.The invention relates to an electromagnetic retarder and generator assembly.