Velocity inlet BC problem

Figd84 · October 14, 2009, 09:52

I have a 5" plate orifice device in a pipe system. The calculated speed at the inlet is 0.61 m/s (20" inlet), that corresponds to 120 lt/s.

I run the calculation and the resulting mean velocity in the orifice is 3.2 m/s, something diferent to the 9.2 resulting from dividing Flow/area.

The fluid is incompresible, any suggestion about it??

Philipov · October 15, 2009, 02:07

Post the whole situation..... what is the BC at the other end? what kind of turbulent model you use? what is the mean velocity after initialization?.....

Figd84 · October 15, 2009, 08:06

I´m using velocity inlet BC (0.61 m/s) and Pressure outlet BC at the other end (Atmospheric, 0 Pa). The turbulence model is k-epsilon with standard wall treatment. The initialisation is 0.61 m/s, calculating from the inlet.

The mean velocity at the inlet is 0.61 m/s in a developed flow section, and into the plate orifice is 5.1 m/s, the calculated velocity there must be 15 m/s according to flow/area on an incompresible flow.

The residuals are 10e-5 and it seems to have a good convergence.

Thanks for reading Philipov.

Philipov · October 15, 2009, 09:47

can you send me the mesh file? I'll try to solve it..

Figd84 · October 15, 2009, 13:34

Where can I send you the files?? mi e-mail is figd84@gmail.com i´ve sent you an e-mail through this forum, don´t know if you get it.

Philipov · October 16, 2009, 01:46

You've mail

October 14, 2009, 09:52	Velocity inlet BC problem	#1
Figd84 Member Felipe Gutiérrez Donoso Join Date: Mar 2009 Posts: 31 Rep Power: 17	I have a 5" plate orifice device in a pipe system. The calculated speed at the inlet is 0.61 m/s (20" inlet), that corresponds to 120 lt/s. I run the calculation and the resulting mean velocity in the orifice is 3.2 m/s, something diferent to the 9.2 resulting from dividing Flow/area. The fluid is incompresible, any suggestion about it??

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October 15, 2009, 02:07		#2
Philipov Senior Member Svetlin Filipov Join Date: Mar 2009 Location: United Kingdom Posts: 176 Rep Power: 17	Post the whole situation..... what is the BC at the other end? what kind of turbulent model you use? what is the mean velocity after initialization?.....

October 15, 2009, 08:06		#3
Figd84 Member Felipe Gutiérrez Donoso Join Date: Mar 2009 Posts: 31 Rep Power: 17	I´m using velocity inlet BC (0.61 m/s) and Pressure outlet BC at the other end (Atmospheric, 0 Pa). The turbulence model is k-epsilon with standard wall treatment. The initialisation is 0.61 m/s, calculating from the inlet. The mean velocity at the inlet is 0.61 m/s in a developed flow section, and into the plate orifice is 5.1 m/s, the calculated velocity there must be 15 m/s according to flow/area on an incompresible flow. The residuals are 10e-5 and it seems to have a good convergence. Thanks for reading Philipov.

October 15, 2009, 09:47		#4
Philipov Senior Member Svetlin Filipov Join Date: Mar 2009 Location: United Kingdom Posts: 176 Rep Power: 17	can you send me the mesh file? I'll try to solve it..

October 15, 2009, 13:34		#5
Figd84 Member Felipe Gutiérrez Donoso Join Date: Mar 2009 Posts: 31 Rep Power: 17	Where can I send you the files?? mi e-mail is figd84@gmail.com i´ve sent you an e-mail through this forum, don´t know if you get it.

October 16, 2009, 01:46		#6
Philipov Senior Member Svetlin Filipov Join Date: Mar 2009 Location: United Kingdom Posts: 176 Rep Power: 17	You've mail