[bibin.sme]

Deart All,

How can I define the wall heat flux boundary condition for mutliphase flows.

For single phase flow we used to define this in "T" file in "0" folder for a particular patch as ( dT/dn = q/kf )

In the similar way if i wants to define for multiphase flow ie as ( dT/dn = q/keff) . where "keff" is a scalar filed and is a function of alpha as keff=alpha*kl +(1-alpha) * kv)

How can I do this? Can anyone suggest a solution for this problem?

Thanks & Regards,
Bibin

[regard]

hi
i use groovy bc for heat flux in the wall
i hope this code can help you

type groovyBC;
valueExpression "327.15";
gradientExpression "q/(K1*alpha1+K2*(1.0-alpha1))";
fractionExpression "0";
variables "q=20000;K1=0.06;K2=0.03;";
timelines ();
value uniform 327.15;

[bibin.sme]

Thank you.... its working

[bibin.sme]

Aslo can u please tell whether it changes at all timesteps or for the first timestep..?? As alpha1 is a function of time...

Thanks &
Regards
Bibin

[regard]

yes
it changes

[bibin.sme]

Thank you so muchh...

Can I ask a quick logical question. Can we model boiling with simple Lee model (Below) without modelling the nucleation site etc..

m ̇ = rc* (1 − alphal)*ρv *(T − T sat)/Tsat for condensation T < T sat
m ̇ = re* alphal*ρl *(T sat− T)/Tsat for evaporation T > T sat

could you please share your thoughts.. any informations or doc??

Regards,
Bibin

[regard]

you can see the phasechangeheatfoam solver in the following link
click here

in this solver lee model is exist