I’m trying to run one of examples called propulsion-6.1.0-2021-06-23_09.44.07.182 available in ValidationCases-6.1.0.zip through this link. My SPIS version is SPIS-6.2.2-win64b.
I’ve noticed a difference in the SPT-100 definition in Group Editor and in SPIS Initialization Summary. For some reason, the temperatures in the Initialization Summary are higher than in Group Editor. I’m attaching a screenshot showing this difference. Can anyone please help me understand why those temperatures are different?
I’m also trying to understand the physics behind the Mach number. I’ve tried using two different equations for the speed of sound (c=sqrt(gamma * R * T / mu), gamma=5/3, and different variations of c=sqrt(k_B * T / mu)), latter were found here). However, so far I couldn’t exactly reproduce the required beam velocity by setting up corresponding Mach number. Can anyone please help me understand the exact definition of the Mach number in this thruster definition model?
Lastly, I’m a bit confused by such large values of ion temperature for the SPT-100 and innerdivergence and divergence angles in Group Editor. If I understand it correctly, in SPIS ions at the thruster exit boundary surface(please correct me if I’m wrong) have both beam velocity (defined through Mach number?) and random velocity components. The latter can be defined through temperature to some point (if we assume a velocity distribution as Maxwellian). So, then, is this temperature responsible for the beam divergence? But if the temperature already defines plume divergence, what’s the meaning of innerdivergence and divergence angles in Group Editors?
I’m still new to SPIS, and I’d be extremely grateful if anyone could help me find the answers to those questions.
Thank you for your support!
All the best,
Egor
The numbers given in the SPIS initialization summary are obtained by performing a dry run of the particle emission from the thruster and computing the moment of the distribution. Thus, the numbers may not exactly be those set in the thruster definition.
Concerning the Mach definition, it assumes gamma=1 (second formula in your post).
I am really interested in this topic, as I am facing the same problems.
Is there a way to set specific values of Isp, power and thrust, starting from the group editor parameters of the ions emitted (temperature, mach, current etc.)?
I’m asking this because right now what I do is tuning the parameters to reach the required values of Isp, power and thrust but it is a very inefficient procedure and not very correct.
Thank you in advance for any insight you can provide.
Hello, I’m currently facing the same issue as you. I also want to process the exit parameters using information like specific impulse and thrust. Have you found a suitable method?
So far, I’m doing the same thing as you are to set precise performance parameter values for the thruster - adjusting and iterating manually. I haven’t tried another approach for this specific problem yet, but my guess is that If you want to automate it, perhaps the fastest solution would be to code your own plugin on Java and integrate it into the common workflow.
Hello. I have been working on setting the thruster exit boundary recently. Currently, the thruster exit boundary I have set is 3.5 mg and 0.25 A. Then, based on the SPT100 exit model, I configured the parameters as shown in the figure. After that, I added probes to the program because I wanted to obtain the temperature distribution. However, after implementing these steps, the program stopped running at 4% without reporting any specific error. I was wondering if you are aware of the possible cause of this issue.
Hello. I have been working on setting the thruster exit boundary recently. Currently, the thruster exit boundary I have set is 3.5 mg and 0.25 A. Then, based on the SPT100 exit model, I configured the parameters as shown in the figure. After that, I added probes to the program because I wanted to obtain the temperature distribution. However, after implementing these steps, the program stopped running at 4% without reporting any specific error. I was wondering if you are aware of the possible cause of this issue.
