Superconducting-coil ST model #65

Closed jonmaddock closed 1 year ago

In GitLab by @pknight on Jul 17, 2014, 14:06

Hi Pete,

I can't remember if I mentioned it previously, but it would be good to turn Bethany's ST centre-column shielding data into a parameterised model and work my CC stress/j_crit spreadsheet model in as well. These are ST specific -- although it would be good if the current density check could call on all available SC models. What's going to be the best way to structure this?

Cheers, Rich

In GitLab by @pknight on Jan 13, 2015, 11:21

It would probably take two weeks of my time to allow a superconducting coil version of the ST model to be implemented.

In GitLab by @hlux on May 16, 2018, 10:34

Hi Rich, I also found this other old issue assigned to you. Would you prefer I close it or can you give more detailed instructions in the Issue. Then we can reassign this to Stuart and he can implement this as he sees fit.

Best, Hanni

In GitLab by @rkemp on May 16, 2018, 11:15

SC_ST_CC.xls

In GitLab by @rkemp on May 16, 2018, 11:20

@hlux @stuartmuldrew Model spreadsheet attached. It's a simple model which tries to model the compressive stress arising from jxB force (ignoring any bursting force, which should probably be added). It allows some optimisation of the current profile within the CC and some other parameters; how much of this could be automated and incorporating the quench protection requirements might take a bit of thought. Happy to discuss if it will be useful for the ST model within PROCESS.

In GitLab by @hlux on May 16, 2018, 13:43

Hi Rich,

thanks for attaching your spreadsheet. I have to admit I still don't understand what it is you have actually done.

First of all, do I understand correctly that your work is completely disjunct from Bethany's work that was mentioned in this issue? Did you mean her work for FNSF she did with Tim Hender? Then we can investigate separately whether it is possible to parametrise this and implement in PROCESS.

Secondly, I understand that your spreadsheet contains a super conducting center column stress vs. critical current model for spherical tokamaks. Where did this come from? Was this fitted to some specific data? Is there any reference document for this model? Are the formlae only documented in that excel spreadsheet? Have you derived them somewhere?

From you table I read this is for Bi-2212 a HTS material. Is this still relevant for current investigations or are other HTS materials being preferred?

Thanks,

Hanni

In GitLab by @rkemp on May 16, 2018, 13:54

My work is disjunct from Bethany's work, which was on centre-column shielding and never parameterised as far as I know. I can't remember if it was for FNSF or not, but she used a simple ST-like geometry and different shielding materials to estimate neutron dose rates to the magnets and try to minimise the shielding required for SC coils in an ST. My spreadsheet is fairly first principles and doesn't require fitting to data (although it should probably be benchmarked against e.g. Ansys if someone can be found to do it). It assumes the coil is made up from a certain fraction of structural material which takes the stress, and a certain fraction of SC which takes the current. It then calculates the field from the centre out to give the critical current density in the SC at all points, and then the jxB force from the outside in to give compressive (radial only) force at the centre of the column. There's a peaking factor on the current profile to allow more current to be shifted to the low- or high-field part of the coil. Bi-2212 was used for the j_crit calculation as it was a parameterisation I had available: anything else could be used. It's a simple model and does not require much derivation, but this (and its implementation into an ST systems code) would be a nice paper since I'm not aware of anything else around which does it.

In GitLab by @jmorris-uk on Jul 17, 2019, 18:04

removed milestone

In GitLab by @wg7580 on Jul 5, 2022, 13:25

closed

ukaea / PROCESS

Superconducting-coil ST model #65