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how to solve the problem in imbalancy in volume flowrate

Ghodsiehsadat Jahanmir

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Dear all,
During my modeling, I faced one problem I could not solve it. I am modeling a domain with 3 Darcy and one laminar flow physics. in sub domain of laminar flow, in one location flow is passing through a very narrow passage with 1 cm length and then the cross section area gets larger. fluid is in-compressible . after solution the volume flow rate I calculated by (average surface velocity) multiple by area is changing about 4 times in that narrow passage that is wrong and it should not change because the inlet and outlet area of that narrow passage is nearly the same. Now I don't have any idea for that. even I make the mesh in narrow passage extremely fine but just the order of velocity increase with that constant ratio. in the second smaller mesh the volume flow rate in inlet of narrow passage is even larger than in main inlet of domain that is wrong.

I do appreciate you to help me.

Best Regards,

2 Replies Last Post 2 feb 2015, 01:58 GMT-5

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Posted: 9 years ago 2 feb 2015, 01:53 GMT-5
How about the mass flow? If that is in error, then you have a problem in the model.

Lasse
How about the mass flow? If that is in error, then you have a problem in the model. Lasse

Ghodsiehsadat Jahanmir

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Posted: 9 years ago 2 feb 2015, 01:58 GMT-5
Thank you for your reply.

I indirectly calculate the mass flow from velocity and area and rho. as fluid is incompressible, the rho is constant and so the volume flow indicate mass flow. because the vol flow are different, so the mass flow are different.

Jahanmir
Thank you for your reply. I indirectly calculate the mass flow from velocity and area and rho. as fluid is incompressible, the rho is constant and so the volume flow indicate mass flow. because the vol flow are different, so the mass flow are different. Jahanmir

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