The equations of motion of ordinary relativistic hydrodynamics are derived by considering conservation equations of the energy tensor and particle number current, where constitutive relations relate the energy tensor and number current to the pressure, energy density, four-velocity, particle number density etc. But suppose I want to describe a fluid consisting of multiple species of particles that can undergo chemical reactions with one another. Then the conservation of particle number of certain species no-longer holds.
Question: How do you derive the resulting equations of motion for chemically reacting fluids? I am most interested in the relativistic case, but might be able to make do with the non-relativistic version.
A quick derivation and sources would be appreciated!