[Pathak]

I want to simulate semi solid die filling using Flow 3D. My alloy is Aluminum alloy A356. I am facing some problems regarding how the flow 3d solver calculates the initial solid fraction of the alloy.
The properties are as follows:
Melting temperature 933 K (T_m)

Eutectic temperature 841 K (T_e)

Initial solute (Si) concentration 0.07 wt fraction Si

Eutectic concentration (Si) 0.126 wt fraction Si
Its written in Flow3D documentation that the solid fraction if calculated by this formula.

f_s = 1/(1-PCOEF)* [(T-T_l)/(T-T_melt)]

where f_s is solid fraction PCOEF = partition coefficient T is the corresponding temperature and T_l is the liquidus temperature.

But suppose if I don’t use macrosegregation module and only semisolid filling I want to do then PCOEF will not be enabled in the panel So how the solid fraction will be calculated?
I am using Hershel bulkley model for my viscosity formulation.

[MuxaB]

without the segregation model, solid fraction is just a linear function of temperature. In any case, after running the preprocessor, look at the prpplt plot file in Analyze - one of the plots is solid fraction vs temperature.

[Pathak]

Hello Mike,

Thanks a lot for reply. But I have one doubt regarding semisolid filling of die. Suppose if we dont use segregation model. Then how one can define the solidus and liquidus temperature of alloy.

[MuxaB]

Hi Pathak,

The solidus and liquidus temperatures are defined directly as input for a given alloy, where you use the segregation model or not. In the former case, they defined the properties at the initial solute content and vary as it varies due to macro-segregation. In the latter case, the initial values of the liquidus and solidus stay constant.

[MuxaB]

Pathak,

This equation for solid fraction is only used when the segregation model is activated. When it is not, the solid fraction is just a linear function of temperature between the liquidus and the solidus.