I'm doing a tracer study using solidworks flow simulation.

What is the unit of measurement of tracer mass fraction?

I would assume it's a ratio of masses, and therefore is a dimensionless value.

Ok, but the value is expressed as a percentage, or not?For example in my study the maximum value of tracer mass fraction is 0.0877.This is 0.0877 % or 8.77 % ?

A ratio typically has the range 0-1, where 0 = 0% and 1 = 100%

I would assume it's a ratio of masses, and therefore is a dimensionless value.