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ukaea / PROCESS

PROCESS is a systems code at UKAEA that calculates in a self-consistent manner the parameters of a fusion power plant with a specified performance, ensuring that its operating limits are not violated, and with the option to optimise to a given function of these parameters.
https://ukaea.github.io/PROCESS/
MIT License
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Resistive magnets mass flow rates #1143

Closed jonmaddock closed 6 months ago

jonmaddock commented 4 years ago

In GitLab by @skahn on Oct 14, 2020, 12:43

Description

The mass flow rate of the TF magnet coolant can be a design constraint.

Proposal

Add a constraint equation on the mass flow rate.

Best regards
Sebastien Kahn

jonmaddock commented 4 years ago

In GitLab by @mkovari on Oct 15, 2020, 09:58

Coolant velocity may be a more suitable constraint - very high velocity tends to lead to vibration.

If you are using a liquid cryogen such as hydrogen or nitrogen then cavitation can impose limits on pressure drop.

If you are using helium vapour or gas then the pumping power is significant and contributes to the recirculating power. As much of the pumping power will be deposited in the helium, this also needs to be taken into account in the cooling of the resistive magnet.

jonmaddock commented 4 years ago

In GitLab by @skahn on Oct 15, 2020, 10:53

@mkovari, the coolant velocity is actually the constraint you use set the cooling system (among the cooling surface fraction and the pipe dimension). Therefore these consideration are already taken into account if you parametrize your magnet properly.

Good points however on the pressure drop and the redeposited heat on the gazeous He. We are however far to be able to take these consideration into account properly as we are using a strawbridge plot scaling for the cryoplant power consumption.

jonmaddock commented 4 years ago

In GitLab by @mkovari on Oct 15, 2020, 11:26

If you are using gaseous helium to cool a cryogenic resistive magnet you should definitely estimate the pumping power.

j-a-foster commented 6 months ago

Looked in the code and the only place that TF coil coolant velocity/mass flow rate is in cntrpst in tfcoil.py. This function is only called for spherical tokamaks so the constraint equation wouldn't apply in general.

Spoke to @mkovari and due to the above and a lack of priority for this to be added, I'm closing the issue.