volume fraction in multiphase problem in fluent
 

hi everyone, i have problem in simulating 2phase flow. the first phase is water and the second phase is nano particle(graphene oxide).the concentration of sulution is 500ppm(part per melion). the problem is that how can calculate volume fraction for secondary phase in inlet bc? can anyone give the formula of converting ppm to volume fraction?

concentration of sulution(nano fluid)=500ppm
volume of sulution=5 liter
volume fraction of secondary phase(nano particle)=?