[Archive] Thruster Shell

Message by Emanuele Ruà:
Hello,
I’m trying to use the thruster shell instruments in order to get the angular distribution of the current density produced by an Electric Thruster. However, the current density values along the centerline are at least an order of magnitude smaller than the experimental results and doesn’t decrease much with the angle while the integrated current is comparable with the expected beam current.
Is the measured current density obtained by interpolation from the nodes of the numerical grid?
What mesh size do you usually use in order to get meaningful results in the area where you want to perform this measurement?
Thanks,
Emanuele

Message by Jens Laube:
Dear all,
I would like to reopen this thread, as I have the same issue like Emanuele, which I already raised during the last SPINE-Meeting.
I am using the SPIS-version SPIS-Propulsion-6.0.4-linux64b simulating an SPT100 with the generic thruster device and specified a thruster shell as follows to monitor the current density:
Angular extent float 90.0 ! - ! Angular extent in degrees
Angular resolution float 1.0 ! - ! Angular resolution in degrees
instrumentObservationDuration float 1.0 ! s ! observation duration
instrumentOutputLevel int 1 ! - ! level of outputs (0 = nominal
1 = extra ASCII files)
instrumentSamplePeriod float 1.0 ! s ! sampling period
Rotation center distance float 0.0 ! m ! Distance of the rotaion center of the shell from the thruster center
Shell distance float 1.0 ! m ! Distance at which the shell lies
Even if the plume looks correct and also the thruster current and thrust match, the thruster-shell instrument output in “project.spis5\DefaultStudy\Simulations\Run1\NumKernel\Output” provides values, which are about a factor of 20 too low compared to the general experimental data and also the total integrated current from the thruster shell does not match the thruster current at all. Everything is compared in A/m2
Is there a conversion factor to be used for the thruster-shell output?
Thanks a lot for your help!
Jens