species transport model or mixture model?
 

Hi,everybody
now ,i am simulating two liquids mix in a ejector in Fluent 6.3.26.one is water ,the other is prime oil(water soluble). Flow pattern in the jet pump is turbulence.As far as i know,"mixture model "was used to simulate liquid-liquid mix which caused by "turbulance",and "species transport model "was used to simulate liquid-liquid mix which caused by "diffusion".
But "turbulance" and "diffusion" are both occured in my problem,so which "mixture model "should i choose? species transport model or mixture model?
or the exsited fluent model cann't solve my problem?

thx in advance!
achaokaoyan