Electric Machine Cooling via Distribution Annulus and Counter-Flow Ducts
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Solution Overview
Problem
Existing electric machines face challenges in effectively cooling high-power density systems, leading to thermal stress and inefficient heat dissipation due to suboptimal coolant distribution and flow configurations.
Innovation Solution
The electric machine incorporates a distribution annulus that directs coolant into housing coolant ducts, which extend axially beyond the stator, connecting to stator cooling ducts that pass entirely through the stator, ensuring efficient heat transfer and uniform cooling by allowing coolant to flow in opposite directions through the machine housing and stator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If coolant is supplied directly to the stator without a distribution annulus, then the cooling system is simpler, but the coolant distribution is uneven and heat dissipation efficiency is reduced
Solution Approach 1:
A distribution annulus is introduced as an intermediary component between the coolant supply and the stator cooling ducts. This annulus receives coolant from the supply port and distributes it uniformly to multiple cooling ducts through distribution openings, ensuring even coolant flow and effective heat dissipation across the stator without requiring complex individual routing for each duct.
2Device complexity
If housing coolant ducts are short and do not extend beyond the stator, then the device complexity is reduced, but the cooling effectiveness of both the machine housing and stator is insufficient
Solution Approach 1:
The cooling system is segmented into two distinct functional parts: housing coolant ducts that cool the machine housing and stator cooling ducts that cool the stator. The housing coolant ducts extend beyond the stator to provide dedicated cooling path for the housing, while stator cooling ducts pass entirely through the stator. This segmentation allows each component to be optimized for its specific cooling requirements, achieving effective cooling of both the housing and stator simultaneously.
3Device complexity
If coolant flows in only one direction through the stator, then the flow path is simpler, but the heat transfer efficiency and thermal stress distribution are suboptimal
Solution Approach 1:
The coolant flow direction is inverted in different sections of the cooling system. Housing coolant ducts extend in one axial direction beyond the stator, while stator cooling ducts pass entirely through the stator in the opposite axial direction. This counter-directional flow arrangement optimizes heat transfer efficiency by creating favorable temperature gradients and ensures uniform cooling distribution, reducing thermal stresses through the stator.
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 achieves effective heat transfer between the machine housing and stator, ensuring efficient heat dissipation even at high power densities, minimizing thermal stresses through uniform coolant distribution and hydraulic equalization.
Implementation Method 1
The cooling of the electric machine accomplished in this way ensures both a cooling of the machine housing by the flow through the housing coolant ducts, which are in a heat transfer connection with the machine housing or are formed on or in the machine housing, as well as a cooling of the stator
Data Source
AI summary
An electric machine having a stator arranged in a machine housing and a rotor mounted rotatably relative to the stator about an axis of rotation, wherein the machine housing includes at least one coolant inlet port for supplying coolant to the machine housing and at least one coolant outlet port for draining coolant from the machine housing. It is provided that the coolant inlet port empties into a distribution annulus and several housing coolant ducts emerge from the distribution annulus and extend beyond the stator, when viewed in the axial direction, and are connected fluidically, on their side facing away from the distribution annulus, to stator cooling duct inlets of stator cooling ducts formed in the stator, which pass entirely through the stator in the axial direction.