Learning Forum

[Chris_g]

Hi,

I am developing a 2-way coupled Rocky-Fluent simulation including gas-particle reactions using a custom module. I am wondering how to include reaction heat and to account for the enthalpy of released gases. According to the manual I have the following functions: add_heat_transfer/set_heat_transfer, add_explicit_fluid_heat_transfer_rate, add_implicit_heat_transfer_rate

From my understanding the "add/set_heat_transfer" functions only affect the particle temperature. What about the add_explicit/implicit_fluid_heat_transfer_rate? Do they only provide a source term to fluent or do they also influence the particle energy equation? What is the difference between explicit and implicit heat transfer?

Thanks for your help!

 

[Lucas Bertollo Baggio]

Hello,

You are correct. The _heat_transfer only affects the particle energy equation. The add__heat_transfer_rate provide a heat source to Fluent. 

The heat source is usually computed as S = Beta * (Tp - Tg), where Beta is the heat transfer coefficient, and T_p and T_g are the particle and fluid temperature, respectively. The explicit part will be obtained from Beta * Tp and implicit part is Beta itself since we don't know the fluid temperature of the cell in which the source term will be applied to. This information is still on Fluent's side. 

Best regards,

Lucas

[Chris_g]

Thank you for the information!

What values do these functions expect?

I've set up some test cases with a single particle. When I pass nondimensionalized 10W (or 100/1000) with add/set_heat_transfer I get 5-20 Watts more when I evaluate Sum:Solid Explicit Heat Transfer Rate*CellVolume and Particle temperature (m*cp*dT)

For add_explicit_heat_transfer_rate I can't seem to get realistic values whether I pass nondimensionalized Joule, Watt or Watt/cell Volume