How to calculate density of solid phase

zhou

hello, when I calculate the solid phase flow field using slip-diffustion model, I do not know hot to calculate the solid density. Can I calculate it using the continueous eqation of solid phase like calculating the K or E ?How can I essure the mass conservation of solid phase?(the assumptions is that the solid phase is not dense phase. the volume of solid occupying and the pressure of solid providing are ingored).. I am a beginner, So I need help. YOur reply will be very appreciated.!