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

How to calculate specific heat of mixture?

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

Reply
 
LinkBack Thread Tools Display Modes
Old   March 22, 2002, 21:46
Default How to calculate specific heat of mixture?
  #1
Seaspace
Guest
 
Posts: n/a
Hi, everyone,i am researching combustion of mixture between methane and air in porous media.But i do not know how to describe constant presssure specific heat,viscosity,enthalpy and heating value of the mixture.If anybody know ,please tell me.Thanks!!!
  Reply With Quote

Old   March 23, 2002, 20:54
Default Re: How to calculate specific heat of mixture?
  #2
Dean
Guest
 
Posts: n/a
Check out any of the books on combustion theory, such as the class "Combustion Theory" by Forman Williams.
  Reply With Quote

Old   March 24, 2002, 00:15
Default Re: How to calculate specific heat of mixture?
  #3
seaspace
Guest
 
Posts: n/a
Thanks for Dean's respones,but i checked some books on combustion,but no data provided about constant presssure specific heat,viscosity,enthalpy and heating value of the mixture.Can you give me more imformation? Thanks again!
  Reply With Quote

Old   March 24, 2002, 18:30
Default Re: How to calculate specific heat of mixture?
  #4
Jim Park
Guest
 
Posts: n/a
I think everything you need can be calculated from the text book by Bird, Stewart, and Lightfoot, "Transport Phenomena." This is a classic for chemical engineers and has been around in various editions since at least the 60's.

It allows you to calculate at least estimates of the info you're seeking from first principles (molecular weight, etc).

Publisher is John Wiley.
  Reply With Quote

Old   March 24, 2002, 22:50
Default Re: How to calculate specific heat of mixture?
  #5
Neale
Guest
 
Posts: n/a
For mixtures of pure substances, especially ideal gases, you can just assume an ideal mixture. Mixture properties are defined as the mas fraction weighted sum of the component properties. Any undergraduate thermodynamics text should cover ideal mixtures in more detail.

Neale.
  Reply With Quote

Old   March 25, 2002, 02:55
Default Re: How to calculate specific heat of mixture?
  #6
Dean
Guest
 
Posts: n/a
Ok, I get it -- you want numbers, not the theory. Everything you need you should be able to dig out of GRI Mechanism 3.0 available at http://www.me.berkeley.edu/gri_mech The transport coefficients are given in the form of Lennard-Jones parameters, so you will have to dig out the formulas for viscosity, etc, including the mixture rules, from someplace such as Bird, Stewart, and Lightfoot. One point about combustion: to get the temperature right, you have to include the temperature dependence of the specific heats. Also, you need to get T right to get the chemistry right because the reaction rates depend exponentially on T.

Perhaps I can be more specific if you describe your problem in more detail. Premixed or diffusion flame? How much detail in the chemistry?
  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
UDF for specific heat p_agoodboy Fluent UDF and Scheme Programming 9 November 26, 2014 11:58
Cp (Specific heat) UDF. When/what version??? agg Fluent UDF and Scheme Programming 7 May 3, 2013 09:17
how to Calculate heat flux??? sandip Main CFD Forum 0 December 4, 2009 05:58
Particle solid specific heat variable with temperature pantarei83 CFX 3 June 10, 2009 18:06
Integral specific heat Steve Amphlett Main CFD Forum 0 August 25, 2000 09:51


All times are GMT -4. The time now is 23:05.