Re: [sparta-users] [EXTERNAL] Mixture Command - Mass or Mole Fraction

[Moore, S. <st...@sa...>]

>Each species has a relative fractional density, such as 0.2, meaning one out of 5 particles is that species

I think this is the definition of mole fraction, i.e. 1 particle/5 particles total = 0.2. 1 mole is just a large number of particles. It is not mass fraction.

Stan
________________________________
From: Woode, Bryan [US] (DS) <Bry...@ng...>
Sent: Tuesday, March 25, 2025 3:50 PM
To: spa...@li... <spa...@li...>
Subject: [EXTERNAL] [sparta-users] Mixture Command - Mass or Mole Fraction

Hello SPARTA Users,

For the mixture command, does the "frac" keyword specify the mass fraction or mole fraction? The manual says "The frac keyword sets a per-species attribute for individual species in the mixture. Each species has a relative fractional density, such as 0.2, meaning one out of 5 particles is that species", but there is no mention of whether this should be the mole fraction or not.

Any insights?


Respectfully,



Bryan Woode | Modeling & Simulation Systems Engineer

Northrop Grumman Corporation | Space Systems

O: 385-442-0669 | Bry...@ng...<mailto:Bry...@ng...>