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total pressure(stagnation pressure) is changing in adiabatic nozzle

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Old   December 29, 2014, 06:48
Default total pressure(stagnation pressure) is changing in adiabatic nozzle
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Riyaz Ahamed S
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Hi
I am trying to solve a simple nozzle problem in Ansys FLUENT.In adiabatic nozzles Total temperature,total pressure should be constant.My solution total temperature is remains constant.But total pressure is not constant in particular place.Please see the attached image. stag pressure.jpg
1)can anyone clarify the reason why it is not constant?
2)How to get constant total pressure?
Thanks in advance.


Details of the problem is given below.

Geometry:geometry.jpg
Material :co2 constant specific heats, molecular weight=44.01 g/mol
density:ideal gas relation.
Model: Invicid model
Boundry condition: 1)INLETressure inlet=6 bar(gauge),Total temperature=427K
2)OUTLET: -6 bar(gauge)
3) operation pressure is 8 bar.
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Old   December 29, 2014, 15:14
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Lucky Tran
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Are you using the pressure based solver or density based solver?

edit* nevermind, I see the screenshot that says dbns
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Old   December 29, 2014, 23:23
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I have used density based solver.
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Old   December 29, 2014, 23:24
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I have used density based solver
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Old   January 1, 2015, 00:34
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Quote:
Originally Posted by sriyaz View Post
Hi
I am trying to solve a simple nozzle problem in Ansys FLUENT.In adiabatic nozzles Total temperature,total pressure should be constant.My solution total temperature is remains constant.But total pressure is not constant in particular place.Please see the attached image. Attachment 36241
1)can anyone clarify the reason why it is not constant?
2)How to get constant total pressure?
Thanks in advance.


Details of the problem is given below.

Geometry:Attachment 36240
Material :co2 constant specific heats, molecular weight=44.01 g/mol
density:ideal gas relation.
Model: Invicid model
Boundry condition: 1)INLETressure inlet=6 bar(gauge),Total temperature=427K
2)OUTLET: -6 bar(gauge)
3) operation pressure is 8 bar.
Anyone please reply to this quoted thread?? it will be very helpful to me.
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Old   January 1, 2015, 03:37
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hey
does happen any oblique or normal shock in the nozzle?
can you attach mach number and pressure contours!?
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Old   January 2, 2015, 00:12
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For the same above mentioned problem, I have changed the mesh to more fine.Here I have attached the results (plots,contour)...

1.Total pressure along the axistotal pressure.jpg
2.Mach no along the axis mach no.jpg
3.Pressure along the axis static pressure.jpg
4.Mach no contourmach no cont.jpg
5.Pressure contourpressure cont.jpg
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