Designing a 3d Printed Hub Motor Cooling Jacket (FSAE)

This was an R&D project I worked on to further my FSAE team's development toward building an AWD electric racecar. The goal is to cool a 20kw electric motor as efficiently as possible in a robust and lightweight design. This project was really interesting because I got to use CFD for the first time. I learned a lot about fluid flow and thermal design, and the nuances of using CFD. 

Temperature streamlines through the cooling jacket

I chose to go with a 3d printed cooling jacket because we have a generous sponsor that does a lot of additive manufacturing for us. 3d printing also allows a lot of the complex geometry on the inside of the part and a lot of design flexibility for heat distribution and weight. 

Part geometry is optimized for 3d printing (screenshot is of post-machined part)

The design primarily focuses on increasing the dwell time of the water around the surface of the motor and the heat distribution. I chose Fluent for the CFD because we have team licenses and other members of the team are familiar with it. The simulation uses a k-omega SST turbulence model with boundary layers on the fluid walls. 

Temperature distribution of the motor surface

Integration into the hub motor assembly

It was also very useful to learn the hand calculations for O-ring sealing, they were more simple than I expected. I also learned a lot about designing for metal additive manufacturing, up until now I've only had experience with hobby 3d printing. I went through multiple revisions and went back and forth with our sponsor on what they will print and what we will post machine to make an accurate part. Designing for thermal warping was the hardest part of the design; it felt like warping was hand-wavey and hard to analyze, most of the design was based on guidelines that are generally good to follow. 

As of right now, the part is currently being 3d printed and we plan on testing it later this year. 

Update: We received the 3d printed part back and we will soon be moving on to machining!