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Old   June 12, 2009, 11:39
Default Constant temperature results
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Hi,

I've just run a simulation of a converging-diverging nozzle using CFX. I pretty much left the Solver Control options as default (i.e. High resolution advection scheme, Autotimescale, Continuity Equation class.)

The problem is in my results the temperature is a constant value. However I can see that the static pressures and the velocities are changing in the nozzle, and they look physical.

Does anyone have any ideas why the temperature is constant? (it should physically change quite a bit in my nozzle)

One thing I need to mention is that the Mach numbers upstream of the nozzle is very low (about 0.03). How does CFX deal with such low Mach numbers? And the maximum Mach number in the throat reaches 1.3.
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Old   June 12, 2009, 11:59
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for high speed flows you need to use total energy heat transfer model to take into account the energy change due to kinetic energy effects

havent done much on high speed flows
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Old   June 12, 2009, 12:44
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Edit: found it.
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Old   June 12, 2009, 13:41
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When I select Total Energy heat transfer model it's gives the following error.


Quote:
There must be an object of type HEAT TRANSFER in the object/FLOW/DOMAINefault Domain/BOUNDARY:inlet/BOUNDARY CONDITIONS but it does not exist
I can't see any option of selecting HEAT TRANSFER in the inlet BCs.
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Old   June 12, 2009, 17:04
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not possible; if you selected a heat transfer model you need to specify a temperature in the inlets

possible out of memory so gui is playing up or your installation is corrupt
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