hi every body i am new user of phoenics i would to know which equation actually phoenics sloves. can you write these equations. i try the phoenics help but its not clear. thabks in advance

PHOENICS solves the Navier Stokes equations, ie conservation equations for continuity, momentum, energy (in terms of temperature, static enthalpy or total enthalpy)and species mass fractions, and also turbulence transport equations. There is an option to solve these equations for a two-phase Eulerian-Eulerian system, and also for a multi-phase Eulerian-Lagrangian system using Lagrangian particle tracking to represent the particulate phases. These equations can be solved in cartesian, cylindrical-polar or body-fitted coordinate systems.

thanks mike for very clear anwser, but i don't know why the Substantial derivative of pressure with negative sign in the R.H.S in the energy equation. i think it should be postive!

Yes, it is positive. For example, when a gas undergoes adiabatic compression the temperature must rise.

mass, energy and momentum