I tried to find out the same geometry but different turbulent model (standard k-epsilon, RNG k-epsilon with low Reynolds number models), how can I compare the results got? Is there any standard procedure to follow?

Compare them on a case with experimental data that is close to yours. Here's an example of how to do it: http://www.daat.com/papers/ke-sec.html

We've done a detailed comparison of EV turbulnece models for few benchmark flows. You can see the following references for the detailed methodology

1. Apsley D.D. and Leschziner M.A., 1999,'Advanced turbulence modelling of separated flow in a diffuser', Flow, Turbulence and Combustion, 63, 81-112. 2. Hasan R.G.M. and McGuirk J.J., 2001, 'Assessment of turbulence model performance for transonic flow over an axisymmetric bump', Aeronautical J., 105 (1043), 17-31.