Modelling an electrical furnace

[Shahab Mohammad Beyki]

Dear FDS experts,

I want to modell an electrical furnace (a 2x2x2 with electric heaters on the 4 walls with a output power of 90kW) with a steel column in the middle. I need to get the temprature on a point close to the column surface.

How can I do that?

Thanks in advance for your help.

Best regards

[Kevin McGrattan]

On the surface or in the gas phase? In any case, read the User's Guide section on Output, in particular device output.

[Shahab Mohammad Beyki]

My first problem is to model the furnace, since it has no fire or combustion.

How should I define this?

On Wed, Jul 6, 2022, 13:28 Kevin McGrattan <mcgr...@gmail.com> wrote:

On the surface or in the gas phase? In any case, read the User's Guide section on Output, in particular device output.

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[Randy McDermott]

Again, read the user guide.  You can also make use of the examples that come with the bundle.

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[o...@aquacoustics.biz]

Have a look at the attached file (rename it .fds) to get some ideas.  This is a model of a real furnace that I'm building in slow time.  It will be interesting to eventually compare the model with the actual performance.  

[Shahab Mohammad Beyki]

That is a great help, but can you please explain your domain please.

What is the specifications of the furnace that you are trying to model?

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[Tim O'Brien]

The furnace dimensions are accurately depicted in the model.  The four heating elements provide ~2 kW to the cavity.  They are an approximation of coiled Nichrome on ceramic formers.  The domain should be self-evident from the model.  You need to rationalize the computational domain for your particular purposes.  Run the model with T_END = 0 and view it in SmokeView, or import it into PyroSim.  The purpose of the model was to examine the effectiveness of the composite insulation (hence the use of HT3D) and confirm the radiation field and convective heat flow for optimal positioning of the control thermocouple and heating elements.  You should have little difficultly scaling the heat, dimensions and insulation.  Depending on your competency with FDS this may take some research and experimentation, but unless you fully describe what you are trying to model, why, for what purpose, and provide an address for invoicing, it is perhaps unreasonable to anticipate that a forum member will write your model for you.     

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[dr_jfloyd]

Nice looking model. A couple of suggestions:

It looks like you have some INERT surface exposed at the ends of your heaters. It might be better to define an ADIABATIC &SURF and use that instead of INERT.  

You may want to try using ZONE and LEAK_PATH rather than having a single grid cell hole for leakage. 

[Tim O'Brien]

Thank you for the feedback and suggestions Jason.

 

I’ll complete the furnace construction and testing before considering further model refinement.  Modeling a-priori is, in my opinion, always more challenging than trying to duplicate the results from an experiment.  The only remaining challenge to construction has been machining the element supports (rescued from radiant space heaters) to length, but a diamond drill and cut-off wheel seem to do the trick.

 

The anticipated gas leakage through the walls  is expected to be limited.  In practice the internal walls are to be lined with a Sodium Silicate/Aluminum Oxide slurry (to protect the calcium silicate board and improve internal re-radiation).  This is also used as an adhesive between layers.  The hole in the centre of the door will actual exit to prevent significant over-pressure from steam and other gas emissions from the charge (a range of interesting Molybdenum catalysts that require long, moderate temperature, say 400°C, heating for activation).

 

 

With kindest regards,

 

Tim   

 

From: fds...@googlegroups.com [mailto:fds...@googlegroups.com] On Behalf Of dr_jfloyd
Sent: Thursday, 7 July 2022 10:32 PM
To: FDS and Smokeview Discussions
Subject: Re: [fds-smv] Modelling an electrical furnace

 

Nice looking model. A couple of suggestions:

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