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 Caty February 3, 2005 21:55

heat release rate in output file

Hello,

does anyone know how to get the chemical heat release rate in the output file?

I need to model a fire that has a heat release of 100 kW and i don't know how to calculate the velocity that must be set at the inlet to coresspond to a heat release of 100 kw.

Can you help me with this?

Thnak you, Caty

 matej February 4, 2005 03:53

Re: heat release rate in output file

(1)you can get the total heat output in out file if you read the heat going in and heat going out the domain. its at the end of out file. You can also plot it, if you make a additional variable given by expression, where you can set Material.ReactionRate (or what is the name of it) and mutliply it with the Heat of reaction. If you define a variable for it, you may see the change of heat release in the domain, if you are happy with summs or averages in volumes or sections, you just use summ or average ot whatever function of ccl and set to monitor this expression in the output setting in pre. It also depends on the combustion model you use...

(2)It is not difficult. For example the velocity of fuel can be given as:

vel=Power/(rho*ReactionHeat*Area)

where Power = 100 kJ/s, Area = is the inlet area

matej

 Caty February 8, 2005 20:23

Re: heat release rate in output file

Thank you very much Matej. I will do as you suggested.

Have a nice day,

Caty

 caty February 14, 2005 08:08

Re: heat release rate in output file

Hi Matej,

I calculated the fire in the way you said, but i think something may be wrong...Can you please have a quick look maybe you figure out what is wrong...

The concrete fire is: Fuel; Propane Power= 980 Kw The burner = 0.61m*1.22 m Reaction Heat= 1650 kj/mol= 37.41 kj/g Fuel density = reference density = pref /(R/mwMixIn*Tref) T ref = 300 mwMixIn= vfC3H8*mwC3h8+vfO2air*mwo2air pref=1010325 Pa ===> Fuel density = 2.2 kg/s Velocity = power / Raect Heat*fuel density*Area =„» velocity= 0.015 m/s

The velocity is seems a little bit to small and I am wondering maybe I did something wrong (the case seems hard to converge).

Do you think that I set the fuel density correct? How you choose this?

caty

 caty February 14, 2005 08:09

Re: heat release rate in output file

The concrete fire is: Fuel; Propane Power= 980 Kw The burner = 0.61m*1.22 m Reaction Heat= 1650 kj/mol= 37.41 kj/g Fuel density = reference density = pref /(R/mwMixIn*Tref) T ref = 300 mwMixIn= vfC3H8*mwC3h8+vfO2air*mwo2air pref=1010325 Pa ===> Fuel density = 2.2 kg/s Velocity = power / Raect Heat*fuel density*Area =„» velocity= 0.015 m/s

The velocity is seems a little bit to small and I am wondering maybe I did something wrong (the case seems hard to converge). Do you think that I set the fuel density correct? caty

 raajgovindan June 13, 2014 02:21

heat release rate in Fluent

hello
can anyone suggest me how to get data of heat release rate for combustion modeling of diesel engine. I am using eddy dissipation model in Fluent...

regards
Rajesh

 singer1812 June 16, 2014 11:06

Try Fluent forum...

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