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About radiation boundary model for transparent walls

Hello all, I have a question.
I am currently doing an analysis involving solar radiation. It is a glass building and I am applying one of the radiation boundary models, transparent, to the boundary, but I have some questions.

In transparent, I need to select wallAbsorptionModel as shown in the figure below, and since I am doing an analysis that includes solar radiation, I have selected the multiBandAbsorption type. However, only absorption and emissivity are set here. If the material is transparent, then transmittance + reflectance + absorptance = 1 should hold, and we need to set the reflectance somewhere.

Quote:

type transparent;
wallAbsorptionEmissionModel
{
type multiBandAbsorption;
absorptivity (0.3 0.7);
emissivity (0.3 0.7);
};

1. In a transparent model, how do you set the reflectance?

2. If I set the absorption and reflection rates, is the transmittance automatically set to satisfy transmittance + reflection + absorption = 1?

I would appreciate it if someone could answer my question.
Thank you in advance.

Hey :)

1. I don't think OpenFOAM can manage a semi-transparent boundary condition at this moment, but please have someone else confirm. AFAIK, there is only the opaqueReflective condition that have a reflective coefficient:

Code:

type        opaqueReflective;



fd          0.0;  //reflected fraction



wallAbsorptionEmissionModel

{

    type            multiBandAbsorption;

    absorptivity    (0.3 0.7);

    emissivity      (0.3 0.7);

};

2. I guess so.

Good luck!

Thank you for reply!

I see that OpenFOAM can not manage a semi-transparent boundary condition at this moment.

Thank you for your instruction!