Missing Mc/MO2 term in coalChemistryFoam diffusion limited reaction mode

DustExplosion · July 20, 2017, 08:35

As the title says, I cannot seem to find this term in the COxidatioDiffusionLimitedReaction source code.

The diffusion limited reaction is described in this thesis: http://publications.rwth-aachen.de/r...files/5065.pdf, page 193, equation 3.72.

$\frac{\partial m_{c}}{\partial t} = 4 \pi d_{p} \frac{D_{O_{2}} Y_{O_{2}} T_{g} \rho_{g}}{\nu_{O_{2}} \left(T_{p} + T_{g}\right)} \frac{M_{c}}{M_{O_{2}}}$

The original author is Fields (http://ac.els-cdn.com/00102180699000...e4b8974e8b1a32) and I double checked the derivation and it matches 3.72 above (in Fields you need to recognize that 24 = 2*Mc in equation [10]).

However, I cannot find the Mc/MO2 term in the source code for COxidationDiffusionLimitedRate<CloudType>::calcula te, only the rest of the equation.

Code:

 
    // Change in C mass [kg]
    scalar dmC = 4.0*mathematical::pi*d*D_*YO2*Tc*rhoc/(Sb_*(T + Tc))*dt;

    // Limit mass transfer by availability of C
    dmC = min(mass*fComb, dmC);

    // Change in O2 mass [kg]
    const scalar dmO2 = dmC/WC_*Sb_*WO2_;

    // Mass of newly created CO2 [kg]
    const scalar dmCO2 = dmC + dmO2;

    // Update local particle C mass
    dMassSolid[CsLocalId_] += dmC;

Does anyone know what I am missing or where the term went?

It might be related to the fact that the thesis above says Mc/MO2 = 1/2 (also on page 193), which I do not understand (Mc/MO2 = 12/36 = 1/3), but I can't figure it out.

Any thoughts or even other references for diffusion limited surface reaction would be tremendously helpful (I am ready to publish a paper, but just can't figure this equation out!)

Thanks in advance!

Chris

DustExplosion · July 25, 2017, 08:41

Anyone have any thoughts on this?

Thanks!

Chris

July 20, 2017, 08:35	Missing Mc/MO2 term in coalChemistryFoam diffusion limited reaction mode	#1
DustExplosion Member Chris Cloney Join Date: Jun 2016 Location: Halifax, Canada Posts: 62 Rep Power: 9	As the title says, I cannot seem to find this term in the COxidatioDiffusionLimitedReaction source code. The diffusion limited reaction is described in this thesis: http://publications.rwth-aachen.de/r...files/5065.pdf, page 193, equation 3.72. $\frac{\partial m_{c}}{\partial t} = 4 \pi d_{p} \frac{D_{O_{2}} Y_{O_{2}} T_{g} \rho_{g}}{\nu_{O_{2}} \left(T_{p} + T_{g}\right)} \frac{M_{c}}{M_{O_{2}}}$ The original author is Fields (http://ac.els-cdn.com/00102180699000...e4b8974e8b1a32) and I double checked the derivation and it matches 3.72 above (in Fields you need to recognize that 24 = 2Mc in equation [10]). However, I cannot find the Mc/MO2 term in the source code for COxidationDiffusionLimitedRate<CloudType>::calcula te, only the rest of the equation. Code: // Change in C mass [kg] scalar dmC = 4.0mathematical::pidD_YO2Tcrhoc/(Sb_(T + Tc))dt; // Limit mass transfer by availability of C dmC = min(massfComb, dmC); // Change in O2 mass [kg] const scalar dmO2 = dmC/WC_Sb_WO2_; // Mass of newly created CO2 [kg] const scalar dmCO2 = dmC + dmO2; // Update local particle C mass dMassSolid[CsLocalId_] += dmC; Does anyone know what I am missing or where the term went? It might be related to the fact that the thesis above says Mc/MO2 = 1/2 (also on page 193), which I do not understand (Mc/MO2 = 12/36 = 1/3), but I can't figure it out. Any thoughts or even other references for diffusion limited surface reaction would be tremendously helpful (I am ready to publish a paper, but just can't figure this equation out!) Thanks in advance! Chris

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July 25, 2017, 08:41		#2
DustExplosion Member Chris Cloney Join Date: Jun 2016 Location: Halifax, Canada Posts: 62 Rep Power: 9	Anyone have any thoughts on this? Thanks! Chris