Electric Machine Cooling Jacket with Throttled Inlet Flow
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Solution Overview
Problem
In flat jacket cooling systems for electrical machines, the coolant flow tends to separate, leading to dead water areas with low flow velocities and heat transport, resulting in increased temperatures due to the large width-to-thickness ratio of the cooling channels, which is challenging to address without complex guide vanes or increased packaging.
Innovation Solution
A cooling unit design featuring a trough-shaped inlet region with a larger channel height, a throttle region with reduced channel height, and a normal region with intermediate channel height, which ensures even distribution of coolant flow and reduces pressure losses, allowing for efficient heat transfer across the entire width of the cooling channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a flat cooling channel with large width-to-thickness ratio is used, then the cooling channel can extend circumferentially around the jacket with width corresponding to large proportion of axial length, but the coolant flow separates and concentrates in small areas creating dead zones
Solution Approach 1:
The cooling channel is designed with varying local properties: the thickness varies circumferentially with a thinner section (minimum thickness) and thicker sections. This non-uniform thickness distribution creates corresponding variations in flow resistance that guide the coolant flow more evenly across the width of the cooling channel, preventing flow separation and dead zones while maintaining the large width-to-thickness ratio advantage
Solution Approach 2:
The patent changes the geometric parameters of the cooling channel by varying the thickness circumferentially. This parameter variation (from minimum to maximum thickness) modifies the flow characteristics and pressure distribution, ensuring uniform coolant distribution across the channel width without requiring additional structural elements
2Reliability
If guide vanes are added to ensure uniform flow distribution, then flow separation is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent removes the need for separate guide vanes by integrating the flow guidance function directly into the cooling channel geometry itself. The varying thickness of the cooling channel wall acts as the flow control mechanism, eliminating additional components and simplifying manufacturing while achieving uniform flow distribution
Solution Approach 2:
The flow guidance function is merged with the cooling channel structure. The cooling channel wall itself, with its varying thickness, performs both the cooling function and the flow distribution function that would otherwise require separate guide vanes, reducing component count and manufacturing complexity
3Reliability
If radial inflow is used to improve flow distribution, then cooling effectiveness is enhanced, but packaging dimensions increase
Solution Approach 1:
Instead of changing the inlet direction to radial (as in conventional designs), the patent inverts the approach by keeping the axial inlet and instead modifying the cooling channel thickness distribution circumferentially. This achieves the flow distribution benefit of radial inflow without the increased packaging dimensions
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 achieves homogeneous flow distribution and low pressure losses, enhancing cooling effectiveness while being inexpensive to manufacture and requiring minimal additional structural elements, thus improving the thermal management of electrical machines.
Implementation Method 1
The cooling channel has a throttling area adjoining the inlet area in the circumferential direction of the jacket, in which the channel height (or thickness) of the cooling channel, viewed radially in the jacket, is less than in the inlet area
Implementation Method 2
energy conversion processes dissipate power loss in the form of heat. Therefore, efficient heat dissipation or cooling is advantageous
Implementation Method 3
Jacket cooling systems using a fluid such as water as a coolant are particularly suitable for this purpose
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a cooling unit (300) for an electric machine, comprising a jacket (301) that is at least substantially hollow cylindrical, a cooling channel (310) formed in the jacket which extends in the circumferential direction (U) of the jacket with a width (B) corresponding to a large proportion of the axial length of the jacket, and an inlet (302) and an outlet (303) for coolant which are connected by means of the cooling channel (310) and which are each arranged at an axial end of the jacket (301), wherein the cooling channel (310) has a trough-shaped inlet region (320) adjoining the inlet (302) which extends from the inlet (302) in the axial direction of the jacket over the width (B) of the cooling channel, and wherein the cooling channel (310) has a throttle region (330) adjoining the inlet region (320) in the circumferential direction (U) of the jacket, in which a channel height of the Cooling channel, viewed in the radial direction of the jacket,is lower than in the inlet area (320), as well as an electric machine and a method for manufacturing it.