two fluid, volumetric/mass flow rate at different volume fractions

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 November 26, 2014, 04:25 two fluid, volumetric/mass flow rate at different volume fractions #1 New Member   Véronique Penin Join Date: Mar 2014 Location: Lyon, France Posts: 21 Rep Power: 12 Hi Everybody, Context : multiphasic turbomachinery (water : continuous fluid/air: dispersed fluid), frozen rotor, inhomogeneous Model, fluid dependant. I have to run a lot of simulations with different volumetric flow rate at different volume fractions to compare with experimental results. No problem with one-fluid calculation, where the convergence is checked by a monitor point MASSFLOW = massFlow()@S1 Outlet (the inlet condition is the mass flow on RI Inlet, and it easy to choose the mass flow rate corresponding to the experimental volumetric flow rate). With the two-fluid simulation, I can't use the mass flow rate as an inlet boundary condition, so I use normal speed as inlet boundary condition. My problem is the correspondance between the inlet velocity and the volumetric flow rate (checked by my monitor point and the mass flow rate) in function of the volume fraction. How is calculated the "massflow()" with my two-fluid simulation in function of the volume fraction? (Is (alpha*rho_alpha + (1-alpha)rho_beta) * Velocity * Surface ?) Or how can I set the inlet velocity to be sure that it corresponds to the good volumetric flow rate at a given volume fraction? Thanks a lot Véronique

 November 26, 2014, 05:24 #2 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,727 Rep Power: 143 The CEL expressions are described in the documentation. But for massflow it is simply the density times normal velocity integrated over the boundary - where density and velocity are phase weighted.

 November 26, 2014, 05:30 #3 New Member   Véronique Penin Join Date: Mar 2014 Location: Lyon, France Posts: 21 Rep Power: 12 Yes, I read the documentation, but il was not clear for me. Thanks to confirm that mass flow are phase weighted. Véronique

 Tags cfx, inlet boundary condition, mass flow rate, two fluids

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