CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > CFX

Density of fluid with respect to temperature and pressure

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Display Modes
Old   November 3, 2011, 15:16
Default Density of fluid with respect to temperature and pressure
  #1
New Member
 
Akash
Join Date: Sep 2011
Posts: 12
Rep Power: 5
akash_max is on a distinguished road
Hi All,

I not able to find how to input material property for the fluid(diesel) with respect to temperature and pressure. I have complete data that is pressure range 0 to 2000 bar and temperature range 0 to 200 degree Celcius.

Do i need to write a expression to it or any way i can just feed the excel data into the CFX where in it produces the graph and uses the same.

Similarly I need to give cavitation saturation pressure with respect to temperature.

If this is done then i can run my model with thermal conditions first and then the cavitation model to find the effect of thermal effects on cavitation.

I need to check out with raise in temperature how much the cavitation raises as the fluid passes through different orifice.

I need to also give specific heat capacity with respect to temperature and also the dynamic viscosity with respect to temperature.

I am using thermal energy with inlet as total pressure and temperature and outlet as static pressure. Wall being the adabatic.

Kindly help me out resolving this issue.

Best Regards
Akash A V
akash_max is offline   Reply With Quote

Old   November 3, 2011, 16:46
Default
  #2
Senior Member
 
Join Date: Apr 2009
Posts: 516
Rep Power: 12
stumpy is on a distinguished road
What you want is bi-linear interpolation since the density depends on two variables. There's no built-in bi-linear interpolation in CFX-Pre, so yes, you need to come up with an expression that describes the density as a function of (T,p). I don't think Excel can curve fit a bi-linear function, but it would be nice if it could (and please tell me how to do it!). Anybody know of any software that can do that curve fit?
stumpy is offline   Reply With Quote

Old   November 4, 2011, 09:12
Default
  #3
New Member
 
Akash
Join Date: Sep 2011
Posts: 12
Rep Power: 5
akash_max is on a distinguished road
Hi,

Thanks for your reply.

I would request to kindly send me formulae for density variation with respect to temperature and pressure separately. (Density with repect to temp)( Density with repect to temp)

So that I will assign them individually and check how much is the variation.

Please let me know the CEL function for above mentioned variations.

Thanks in Advance

Regard
Akash A V
akash_max is offline   Reply With Quote

Old   November 6, 2011, 05:54
Default
  #4
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 10,824
Rep Power: 85
ghorrocks has a spectacular aura aboutghorrocks has a spectacular aura aboutghorrocks has a spectacular aura about
You already have defined the density as a function of pressure. Just do the same for temperature and it is straightforward from there.
ghorrocks is offline   Reply With Quote

Old   November 6, 2011, 10:00
Default
  #5
Member
 
Mauricio Labarca
Join Date: Aug 2009
Posts: 35
Rep Power: 8
mauricio is on a distinguished road
Try a software like Curveexpert to find a fit for your temperature and pressure data points. The just use that expression in the material properties. Do check how precise is the fit though.
mauricio is offline   Reply With Quote

Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Calculation of the Governing Equations Mihail CFX 7 September 7, 2014 06:27
Water subcooled boiling Attesz CFX 7 January 5, 2013 04:32
mass flow in is not equal to mass flow out saii CFX 2 September 18, 2009 08:07
How to apply negtive pressure to outlet bioman66 CFX 5 June 3, 2006 01:40
Terrible Mistake In Fluid Dynamics History Abhi Main CFD Forum 12 July 8, 2002 09:11


All times are GMT -4. The time now is 03:06.