Initial density of MATL layer

[r-broek]

Dear developers,

I'd like to confirm if ML%RHO_S in e.g. wall.f90 represents the initial density of the MATL layer (user input), given as rho_s(0) in the FDS user's guide 9.2.2.

[drjfloyd]

rho_s(0) is not used in pyrolysis in the current release of FDS. Neither Eq. 9.1 nor Eq 9.2 contain rho_s(0). The note at the bottom of the page for those equations that has rho_s(0) is instructions on how to convert the A input for older versions of FDS where rho_s(0) was in the pyrolysis equaiton.

ML%RHO_S is not rho_s(0). ML%RHO_S is the DENSITY input on MATL. It will be rho_s(0) when the MATL has a MASS_FRACTION of 1, otherwise it will be a lower value.

[r-broek]

Yes I am aware rho_s(0) is not currently used for pyrolysis reactions, but I figured that perhaps the variable still existed within the source code. I wanted to use it for converting A values automatically. Thank you for explaining what ML%RHO_S represents.

[drjfloyd]

Look at read_surf in read.f90. The block of code at line 8535 sets up the intial density and material mass fractions for each layer in a surf.

[r-broek]

I will take a look. Thanks again!