# 1D point sink boiling model !!! (PROJECT)

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May 21, 2019, 06:39
Boiling model in openfoam !!
#1
Senior Member

Kumaresh
Join Date: Oct 2016
Posts: 324
Rep Power: 9
Hello Foamers,

My topic of research is to build the 1D mathematical model for simulating the coal pyrolysis in OpenFOAM. My question is all about solving "Boiling of moisture" based on 1D point sink boiling model.
When I come across the boiling topic in openFOAM, I found some existing solvers like interFoam, compressibleInterFoam, interPhaseChangeFoam (based on VOF - fluid-fluid interaction) and so on, where I am not sure it is related to my topic.

As explained in attachment (figure), due to supply of heat from the wall ==> the moisture content present in the coal gets evaporated at 100deg. The rate of boiling (r) is calculated with respect to the moisture content and rate of progression of boiling plane ==> Finally, rate of boiling (r) will be called manipulated in ENERGY equation as a source term. This problem is solely dependent on main variable temperature (T) with no pressure and velocity terms. However, I understand the flow physics, I couldn't able to find any existing solvers related to this topic to find my way or any clues to set-up my simulation fro boiling. So, I would like to know where should I need to start, how to proceed and move on !!!
Kindly someone share their ideas please. Thank you !!!
Attached Images
 Model with conditionss.jpg (134.9 KB, 20 views)

Last edited by Kummi; May 24, 2019 at 01:33.

 May 22, 2019, 10:17 #2 New Member   Dinesh Join Date: Jun 2018 Posts: 15 Rep Power: 6 Could you please explain about the equations mentioned - quite clearly..

 May 22, 2019, 12:21 #3 Senior Member   Kumaresh Join Date: Oct 2016 Posts: 324 Rep Power: 9 Hello Dinesh, Thank you for your reply ^^ ☞By default, coal present inside the chamber contains moisture content (1~10% approx). By supplying heat from the wall, the moisture (in coal) will be evaporated around T=100deg. ☞ In order to define this scenario, the mathematical model is defined based on energy (T) equation with source term to capture the flow physics of moisture evaporation. ☞It is assumed that the: (i) At all high temperature zones - (with respect to boiling plane (xb))– moisture content (w=0) is zero. (ii) Temperature (∂T/ ∂x=0) is constant (in every plane section) along axial distance. ☞The variation of moisture content at lower temperature (T<100) is captured by the rate of boiling (r) when approached through point sink ideology (negative source model which absorbs everything). ☞The calculated rate of boiling (r) is multiplied with [2.257*e6] to substitute as source term in main energy equation as shown in figure above. To implement point sink ideology  I don’t have any clue to implement it in openFOAM. Since I am new to openFOAM, adding such source terms in main equation seems to be quite complex. Thank you.. Hope u understand !!

 May 22, 2019, 12:24 #4 Senior Member   Kumaresh Join Date: Oct 2016 Posts: 324 Rep Power: 9 Have you worked with such idealogy before ?

 May 24, 2019, 01:37 #5 Senior Member   Kumaresh Join Date: Oct 2016 Posts: 324 Rep Power: 9 Spark of ideas from anyone ? may give better plan to approach my problem.. Hoping toooo !!

 February 8, 2021, 10:03 #6 New Member   hamdani hakim Join Date: Mar 2019 Posts: 16 Rep Power: 5 Hi kummi, You work on 1D probleme, in compressibleInterFoam, Me too i work on 1D two-phase-flow compressible. I hope that you resolve your probleme Please, I would like to know how you chose your discretizations (fvSchemes and fvSolution) for your problem ?? best regret,

February 8, 2021, 11:00
#7
Senior Member

Kumaresh
Join Date: Oct 2016
Posts: 324
Rep Power: 9
Hello Kimou,
Here is the scheme and solution I used.
Quote:
 FoamFile { version 2.0; format ascii; class dictionary; object fvSchemes; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // ddtSchemes { default CrankNicolson 0.9; } gradSchemes { default Gauss linear; } divSchemes { default none; } laplacianSchemes { default none; laplacian(thermo:alpha,h) Gauss linear corrected; laplacian(kappa,T) Gauss harmonic corrected; laplacian(alpha,h) Gauss linear uncorrected; } interpolationSchemes { default linear; } snGradSchemes { default corrected; } fluxRequired { default no; }
Quote:
 FoamFile { version 2.0; format ascii; class dictionary; object fvSolution; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // solvers { h { solver PCG; preconditioner DIC; tolerance 1e-6; relTol 0; } "Yi" { solver PBiCGStab; preconditioner DILU; tolerance 1e-06; relTol 0; } rho { solver PCG; preconditioner DIC; tolerance 0; relTol 0; }; } SIMPLE { nNonOrthCorr 0; } relaxationFactors { equations { h 1; } }
Hope it helps.
Thank you