Mismatch inlet and outlet flow rates
Hello all,
I am currently stuck in a problem with Fluent (18.2) modelisation. I have a simple pipe in which some water is flowing. I used SST model because I want to study transitional regimes. It is a steady/pressure-based/absolute velocity formulation case. No temperature/energy effects are taken here. Operating conditions: pressure=1 atm. The solver method is coupled with Courant number of 10 (mesh ~5E-4) I defined a mass flow inlet: - Reference frame Absolute - Mass flow rate 0.001 Kg/s - Supersonic/Initial Gauge Pressure 0 Pa - Direction specification method: Normal to Boundary - Turbulence: Intermittency 1, Intensity 5%, Viscosity ratio 10 A pressure outlet: - Backflow reference frame: absolute - Gauge pressure 101325 Pa - Pressure profile multiplier - Backflow direction specification method: normal to boundary - Backflow pressure specification: static pressure - Turbulence: Intermittency 1, Intensity 5%, Viscosity ratio 10 No slip condition walls A symmetry (taken into account the hald of pipe) I would say that the calculation converges well and it reach residuals @ 1E-6 smoothly. When I check the flow rate however I have a correct inlet mass flow @ 0.001 Kg/s but an unexpected outlet flow rate @ 0.00125 Kg/s ( greater velocities at the outlet) Have you any ideas of why these two values of mass flow mismatch ? I have no hits of it!:confused: |
Not sure if this would fix it or not, but for your pressure outlet you said that the gauge pressure is 101325 Pa. Should it be 0 Pa? Other than that I've got no clue.
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Yep already set 0 Pa at the outlet because working conditions are 1 atm...
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