### 8.1.2. Particulate Effects to Radiation Transport

When your ANSYS CFX model includes Lagrangian particles, you can include the effect of particles in the radiation model.

For a medium containing gray absorbing and emitting particles, the contribution of the particles to the transport equation for the incident radiation can be written as

| (8–9)

where is the effective emission of the particles and is the effective absorption coefficient. These are defined as follows:

| (8–10)

and

| (8–11)

In Equation 8–10 and Equation 8–11, , , and are the emissivity, projected area, and temperature of particle . The summation is over particles in volume . These quantities are computed during particle tracking in ANSYS CFX.

The projected area of particle is defined as

| (8–12)

where is the diameter of the th particle.

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