  We propose a model to study symmetric binary fluids, based in the mesoscopic
molecular simulation technique known as multiparticle collision, where space
and state variables are continuous while time is discrete. We include a
repulsion rule to simulate segregation processes that does not require the
calculation of the interaction forces between particles, thus allowing the
description of binary fluids at a mesoscopic scale. The model is conceptually
simple, computationally efficient, maintains Galilean invariance, and conserves
the mass and the energy in the system at micro and macro scales; while momentum
is conserved globally. For a wide range of temperatures and densities, the
model yields results in good agreement with the known properties of binary
fluids, such as density profile, width of the interface, phase separation and
phase growth. We also apply the model to study binary fluids in crowded
environments with consistent results.
