Electric Motor Pin-Fin Cooling for High Coolant Flow
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Solution Overview
Problem
Existing electric motor cooling systems face issues with reduced coolant flow rates due to components obstructing the flow path, leading to increased thermal resistance and potential pump degradation.
Innovation Solution
The electric motor features a casing with a coolant inlet opposite a coolant outlet across its central axis, housing a stator with radially extending pin-fins in a staggered arrangement, allowing coolant to flow between the casing and stator, reducing thermal resistance and increasing flow rates through clearances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If components are arranged directly in the coolant flow path to cool the electric motor, then cooling effectiveness is improved, but coolant flow rate is reduced and backpressure increases
Solution Approach 1:
The stator is segmented into multiple independent cooling channels with pin-fins distributed throughout. This segmentation allows coolant to flow through multiple separate paths simultaneously, maintaining high flow rate while providing extensive cooling surface area. The pin-fins are arranged in a staggered pattern that divides the flow path into multiple clearances, preventing flow obstruction.
Solution Approach 2:
The pin-fins extend radially outward from the stator in a direction perpendicular to the main coolant flow direction. This dimensional arrangement allows coolant to flow axially through clearances between pin-fins while cooling the stator circumferentially, effectively adding a radial cooling dimension that does not obstruct the primary axial flow path.
2Temperature
If components are arranged directly in the coolant flow path to cool the electric motor, then cooling effectiveness is improved, but pump backpressure increases leading to degradation
Solution Approach 1:
The cooling system is divided into multiple parallel channels formed by the staggered pin-fins. This segmentation reduces resistance in each individual channel while providing multiple flow paths, thereby maintaining low overall backpressure on the pump while achieving effective cooling across the entire stator surface.
Solution Approach 2:
The pin-fins act as intermediary heat transfer elements that extend into the coolant flow path without fully obstructing it. They provide thermal contact with the coolant while maintaining flow clearance, serving as a mediator between the stator and coolant to transfer heat efficiently without creating excessive backpressure.
3Temperature
If pin-fins are arranged in a staggered configuration to increase coolant flow rate, then thermal resistance is reduced, but device complexity increases
Solution Approach 1:
The pin-fins are arranged in an asymmetric staggered pattern rather than a uniform grid. This asymmetric arrangement optimizes flow dynamics by creating varied clearance paths that reduce thermal boundary layers and enhance convective heat transfer, while the repeating staggered motif keeps manufacturing complexity manageable through pattern repetition.
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 configuration enhances cooling efficiency by increasing coolant flow rates, reducing thermal resistance, and promoting uniform heat transfer from the stator to the coolant, thereby improving motor performance and durability.
Implementation Method 1
transfer heat from the stator to the coolant via the pin-fins
Implementation Method 2
direct the flow of the coolant across surfaces of the pin-fins and through the clearances, which may reduce a thermal resistance of the coolant
Data Source
AI summary
Various methods and systems are provided for thermal management of an electric motor via a coolant flow around portions of the electric motor, where the coolant flow is disrupted by an arrangement of pin-fins. In one example, an electric motor comprises: a casing including a coolant inlet arranged opposite to a coolant outlet across a central axis of the electric motor; a stator housed within the casing and forming a plurality of pin-fins extending straight outward radially, relative to the central axis, from outer circumferential surfaces of the stator in a staggered arrangement around an entire perimeter of the stator; and a plurality of clearances formed between adjacent pin-fins of the plurality of pin-fins, the plurality of clearances adapted to flow a coolant from the coolant inlet to the coolant outlet.