CFD Online Discussion Forums

CFD Online Discussion Forums (
-   FLUENT (
-   -   Need advice on reaction in Turbulent Flow (

Angelo Sozzi March 12, 2005 21:01

Need advice on reaction in Turbulent Flow

I am encountering a weird problem with the fluid density in reactive flows. Problem: A + Radiation --> B in Water (liquid) With A and B properties (density etc.) like water.

The Hydrodynamic Flow with Fluid = H2Ois converged and OK. I add the reaction (see below) and suddenly the density throughout the domain is no longer 998kg/m^3 but 0.734 kg/m^3. Given that i have a massflow inlet this changes my speed from some 0.11-2m/s to over 6000m/s. I seem to have NO influence over the density, whatever I do, once the fluids are in a mixture template.

If you know what I might be doing wrong please let me know.

--------------what I insert ino the mixture----- Define-model-speciesModel: Species Transport * Finite Rate/Eddy Disipaton * Volumetric Reaction * inlet Diff * Diff Energy Source -- Define-Materials-Material Type Fluid use liquid water as basis and create the fluids A and B with the properties of water. - add A, B, Water-liquid to the species list (liquid water is last for bulk) and delete the rest -- Add a reaction A -> B (rate will be defined by UDF later.

iterate and voila density is down to 0.73 even though all three components have a density of 998 ????????

All times are GMT -4. The time now is 00:23.