[Kummi]

Dear Foamers, Help me out here. Attachment gives clear overview. Hereby explaining the gist of my problem. In my work, boiling is considered as a point sink of moisture calculated based on mass and energy balances.

(i) I would like to know as how to implement the Stefan condition (Rankine-Hugoniot condition) based on heat balance (Equ: 10) for moisture in OpenFOAM?

Mass balance (r) = rho * alpha * (dx/dt) [kg/m2.s]
Heat balance (-K dT/dx) = (r) * latent heat [W/m2]

The calculated mass and heat balances are explicitly substituted in energy equation as a source term. (only heat is convected, no velocity and pressure terms here)
ENERGY EQU: rho*Cp*(delT/delt) = del/delx[K*delT/delx ] + r_gas*c_gas*delT/delx + rho*delQ/delT (W/m3)

(ii) The interface (boiling plane) is located based on sign changes technique as xb- & xb+ where, xb = position of boiling plane. Should I need to adopt level set method ? I'm confused here.

REF - Clear details here in this MANUSCRIPT ~ https://sci-hub.tw/https://doi.org/1...361(83)90225-9 Kindly share some advisable methodology in OpenFOAM. Thank you Foamers !!

[Kummi]

Some additional info:
The heat balance equation mentioned above serve as Rankine-Hugoniot ‘‘shock’’ condition which indicates ‘‘interface jump’’ condition expressing energy conservation. At T = 100 ==> the energy undergoes a jump of magnitude based on heat balance term. Figure attached ==> shows how jump occurs during phase transition.

~ No separate transport equations for phase change phenomenon.

Phenomenon ==> when the wet coal is heated up, initially a part of heat is needed for the phase change of the water: so should consider this in the energy equation of the pyrolisis model maybe as additional source term - (r*Cp*delT/Delx) - r= rate of evaporation calculated based on mass balance (based on temperature only) stated above.

Someone throw light upon this problem please. Some guiding steps in OpenFOAM..?? Thank you !!

[Kummi]

interface
{ type compressible::turbulentTemperature CoupledBaffleMixed;
value uniform 293;
neighbourFieldName T;
K solidThermo;
KName none; }

Using the above interface condition, the temperature supplied from the wall is converted into heat flux. With this heat flux, how the energy balance across the liquid-gas interface can be established ?

Heat balance (-K dT/dx) = (r) * latent heat [W/m2]

[Kummi]

(i) As seen in the attached image, inside the chamber the energy equation follows, which contains the source term for evaporation as "TEMPERATURE CONVECTION" - there is no velocity and pressure in my case.
(ii) Near the interface [location (2)], by default I have prescribed the condition as "compressible::turbulenttemperatureCoupledBaffleMix ed".
But I require "EVAPORATION INTERFACE CONDITION"

@T=100 [w(moisture content)->at high (-) temperature side =0]
@mass balance (calculated at -> low (+) temperature side)
@then heat balance is formulated at the INTERFACE

REF - Clear details here in this MANUSCRIPT ~ http://sci-hub.tw/https://doi.org/10...361(83)90225-9
Please read my above conditions and correct me if I understood something wrong.
PS: The interface (boiling plane) is located based on sign changes technique as xb- & xb+ where, xb = position of boiling plane. What technique should I need to adopt here? I'm confused here.

On the whole, I am in need of evaporation boundary condition at the interface.

Although I gone through many cases related to this study, unfortunately I'm out of ideas as how to overcome this problem. I would real appreciate if anyone could give me a hint where to look at or point me about the implementation in OpenFOAM.

Thank you Foamers.