Setting up physics for superheated steam

AlanLJ · October 14, 2015, 09:28

Hi,

I am completely new to CFD and have to run a couple of simulations for my university project.

My model is a sootblower lance (essentially a distributing manifold with a closed end). There are 12 nozzles along the length of the manifold that the steam flows out.

I have superheated steam flowing in through the inlet.

I've done the meshing and it looks reasonably good so just onto the physics part now. I have never run a simulation before and I'm not quite sure how to set it up. I'll list my geometry values and inlet conditions below:

Length of manifold = 20m
Inside diameter of manifold = 0.06268m
Nozzle diameter = 16mm throat (convergent divergent)
Inlet mass flow = 2.65kg/s
Inlet pressure = 8 bar
Inlet velocity = 295.815m/s
Inlet Reynolds number = 2196809
Inlet temp = 675K

If anyone could give me any pointers on how to set up the physics or just any advice in general relating to the whole simulation it would be hugely appreciated!

If any further info or screenshots or anything are required just ask.

Thanks for any replied,

Alan

me3840 · October 14, 2015, 19:33

If you have never run a simulation before, this is not necessarily an easy problem to start with.

What does the geometry look like? Are the nozzles flowing out into a large domain, or is this just a pipe flow problem?

You will want to specify the inlet mass flow or velocity, and the outlets' pressures. You haven't said anything about the steam, what is the mass fraction of water to air at the inlet? Are we just moving the steam or is condensation an issue?

AlanLJ · October 15, 2015, 06:04

The focus is just the steam flow through the manifold and the ultimate objective of the project is to try and achieve uniform distribution through all the nozzles. Condensation isn't an issue as the steam will remain superheated the entire time.
The properties of the steam at the inlet are:

Temp: 675K
Pressure: 8bar
Enthalpy: 3269.86kJ/kg
Viscosity: 2.4503E-05

Here is a screenshot of what the lance looks like; huge long manifold with 12 nozzles equally spaced along.

Edit: here's the imgur link, dont think the picture is showing: http://imgur.com/MdEv1Tn

me3840 · October 15, 2015, 16:02

Okay, for this then you need to be using a multi-component gas and just specify one species as air and the other as water vapor.

October 14, 2015, 09:28	Setting up physics for superheated steam	#1
AlanLJ New Member Alan Join Date: Oct 2015 Posts: 4 Rep Power: 10	Hi, I am completely new to CFD and have to run a couple of simulations for my university project. My model is a sootblower lance (essentially a distributing manifold with a closed end). There are 12 nozzles along the length of the manifold that the steam flows out. I have superheated steam flowing in through the inlet. I've done the meshing and it looks reasonably good so just onto the physics part now. I have never run a simulation before and I'm not quite sure how to set it up. I'll list my geometry values and inlet conditions below: Length of manifold = 20m Inside diameter of manifold = 0.06268m Nozzle diameter = 16mm throat (convergent divergent) Inlet mass flow = 2.65kg/s Inlet pressure = 8 bar Inlet velocity = 295.815m/s Inlet Reynolds number = 2196809 Inlet temp = 675K If anyone could give me any pointers on how to set up the physics or just any advice in general relating to the whole simulation it would be hugely appreciated! If any further info or screenshots or anything are required just ask. Thanks for any replied, Alan

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October 14, 2015, 19:33		#2
me3840 Senior Member Join Date: Nov 2010 Location: USA Posts: 1,232 Rep Power: 24	If you have never run a simulation before, this is not necessarily an easy problem to start with. What does the geometry look like? Are the nozzles flowing out into a large domain, or is this just a pipe flow problem? You will want to specify the inlet mass flow or velocity, and the outlets' pressures. You haven't said anything about the steam, what is the mass fraction of water to air at the inlet? Are we just moving the steam or is condensation an issue?

October 15, 2015, 06:04		#3
AlanLJ New Member Alan Join Date: Oct 2015 Posts: 4 Rep Power: 10	The focus is just the steam flow through the manifold and the ultimate objective of the project is to try and achieve uniform distribution through all the nozzles. Condensation isn't an issue as the steam will remain superheated the entire time. The properties of the steam at the inlet are: Temp: 675K Pressure: 8bar Enthalpy: 3269.86kJ/kg Viscosity: 2.4503E-05 Here is a screenshot of what the lance looks like; huge long manifold with 12 nozzles equally spaced along. Edit: here's the imgur link, dont think the picture is showing: http://imgur.com/MdEv1Tn

October 15, 2015, 16:02		#4
me3840 Senior Member Join Date: Nov 2010 Location: USA Posts: 1,232 Rep Power: 24	Okay, for this then you need to be using a multi-component gas and just specify one species as air and the other as water vapor.