# mass flow rate...

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 November 19, 2013, 15:27 mass flow rate... #1 Member   ziehjay Join Date: Jul 2013 Posts: 45 Rep Power: 12 Hey guys, i have a specific question referring to my simulation in OF. my simulation is about a multiphase flow, consisting of water and sand. i have to variate my mass flow rate of sand and show its effects on pressure. but i dont know how to variate it in my simulation. there i no parameter which stands for the mass flow rate of sand. btw: the mass flow rate is a calculated calue from a trivial formular. i have the sand concentration (wt %), which is the solution of mass flow rate sand / (mass flow rate water + mass flow rate sand)...the parameters of the velocity, the surface of my inlet where the multiphase fluid flows out and the densitiy of sand and water is known. so its just simple mathemtatics but i dont know hw to set the mass flow rate of sand as an parameter. if there is someine who is willing to look at my simulation, is prepared a download link. so you can just take a look at it. i think its a very ease problem, but i cant find the solution. so sorry for this stupid question, please help me out guys. just write a message and i will send you the link THANKS!

 December 2, 2013, 00:09 #2 Member   Christian Butcher Join Date: Jul 2013 Location: Japan Posts: 85 Rep Power: 12 Are you using interFoam? If so, are the fractions of sand and water controlled by your alpha1 field? My understanding of your question is that you have some sort of pipe/channel through which both sand and water are flowing, with an inlet at one end and an outlet at the other end? When you say that the "surface of my inlet where the multiphase fluid flows out" is known, do you mean that you know the position/shape of the surface, or that you know the other parameters (density, velocity, concentration) at this surface? If you have a mixture of sand and water input at the entrance, and a known concentration, I would imagine that you can set alpha1 BC on the inlet to a fixedValue condition, and give the value=concentration, as a value between 0 and 1. IF you need the sand to be at the bottom, but of a thickness that varies between simulations, then you can use the setFieldsDict to describe a box in which you set the value of alpha1 to either 0 or 1, whichever corresponds with the sand, and then use your alpha1 boundary condition file to describe a uniform default of the other value (ie the water). If I have horribly misunderstood your problem, I apologise. Christian