Using Flow Simulation HVAC: Joule Heating to help design a fuse.
When most people think of SOLIDWORKS Flow Simulation, they think of studying flow though pipes, heat exchangers, or flow over airfoils and around assemblies. When I think of Flow Simulation, I think of this:
Flow Simulation is a multi-purpose tool that has much more to offer than just fluid flow. Today, I am going to explore a feature of Flow Simulation that comes with the HVAC module: Joule Heating. As the title of this blog suggested, we are going to design a fuse to blow as close to 5 Amps as possible. We will set up a study, have Flow change the thickness of the fuse filament, and watch the melt temperature.
We start with a fuse assembly. The metal is made of Tin, and the body is made of generic plastic.
The Tin material has a melt temperature of roughly 504 Kelvin (448 F). Once we exceed this, the fuse will melt and open the circuit.
The model is set up so that one dimension controls the thickness of the fuse element. In our initial model, it is 0.381mm. We will modify this dimension in our parametric study.
For my initial run, I set a 5 amp Current In and Current Out boundary condition in the Flow simulation and made sure “Heat conduction in Solids” was turned on.
We see here that the maximum temperature the fuse reaches is only about 188 F. Well below the melting point.
Rather than changing the geometry manually, I will tell Flow Simulation to vary the thickness and report this plot back to me.
By running a “What If” parametric study, I can specify a dimension and its bounds.
In this case, I am varying the thickness dimension from 0.1mm to 0.2mm in increments of 0.01mm (for a total of 11 studies).
Once it runs all the scenarios, it will output snapshots of any goals or plots that I specify.
We can see here that the filament melts somewhere between iteration 4 and 5 (0.2032mm and 0.2286mm). These plots are saved as image files in the results directory, so you can access them from outside of SOLIDWORKS.
At 0.2286mm, we have a max temperature of roughly 350F, not enough to melt the filament.
At 0.2032mm, we see that most of the filament is above our melt temperature of 448F.
From this point, I can run another parametric study, further refining the filament size. Since I never left the SOLIDWORKS interface, all my changes have been saved to the file, and the drawings for manufacture will be updated automatically. I can be confident in my design and move to manufacturing more quickly. Thank you, SOLIDWORKS, and thank you, Flow Simulation.
Thanks for reading, and as always, Happy Simulating!