Centrifugal fan simulation

[fnizi.ayoub]

I intend to simulate the flow of a fluid (air with trace of ammonia) aspired with a centrifugal fan. To generate the 3D design and in order to save time I used the CFTurbo software. the question is : should I use an assembly with the CFD formed with the impeller + the inlet  + Volute + the rotating region (the same way the centrifugal pump tutorial was presented on the cfd tutorials), and then i ll assign the fluid to the inlet and volute and steel (for exemple) to the impeller. the main uestion is "is ti necessary to use an assembly with the cfd simulation ?". Thanks in advance. 

[Jon.Wilde]

Hi,

Are you using Autodesk CFD or CFTurbo? If the latter, maybe it is better to ask over on their forum? I personally have no knowledge of their software to be able to help you reliably 😉

[fnizi.ayoub]

CFTurbo is a design software, the input is the operating point (pression, flow and rotational speed). The software gives you a 3D as output,, it's not used for simulation. Im using autodesk CFD. According to the tutorial of the centrifugal pump on the website, the fan should have 3 parts at least. Please check the following picture of the fan impeller designed with Solidworks (couldn't do it with Inventor, quite ardius) and tell me if I can simulate the flow with this part only. Thnks for your quick reply mr jon. 

[Jon.Wilde]

OK cool, shows what I know 😉

Did you already see the webinar we ran on this topic? It might be a good starting point.

What you are showing here looks totally fine for a simulation though, yes 🙂

[fnizi.ayoub]

Hi mr jon, 

 I ve altered some things in my fan so it can match with the centrif-pump design in the CFD tutorials file. when the simulation is done this is what I get as though there is no flow or no rotation. Please if you have an idea about what would be the problem. Thanks a lot

[Jon.Wilde]

Did you watch the webinar? There is a pdf linked on there also, see here.

I would use this rather than the tutorial.

I can't really comment on this, not enough information. Could you share the design study bar in the image?

[fnizi.ayoub]

Sure, you can find in the pictures the design study bar, the rotating
region, the impeller and the volute (+inlet cone). The rotating region
surrounds the impeller. The materiel Rotor is assigned to inlet cone,
actulaly it's not, the name has changed after charging
the design on CFD (I dont know why)







​

[fnizi.ayoub]

The model I just sent you is not the real model, it's a simple design of an impeller with two blades with a random volute. The purpose is to get familiar with the software so I can understand the steps before I start the project. This is what I get when display the static pression.

[Jon.Wilde]

Did you see the webinar and document I linked to above? These are so super helpful.

If you follow the steps in there, you should be fine.

I can't see the design study bar but looking at the model, you need longer inlets and outlets - as per the guide, check it out 😉

[Anonymous]

A centrifugal fan is a mechanical device for moving air or other gases in a direction at an angle to the incoming fluid. Centrifugal fans often contain a ducted housing to direct outgoing air in a specific direction or across a heat sink; such a fan is also called a blower fan. Centrifugal force is used as a main principle for the kinetic energy produced by the impeller to the air/gas which is used as a fluent. By this principle the gas enters in to the
impeller and thrown off by creating kinetic energy at the exit. As a result, the pressure is measured in terms of kinetic energy because of casting and duct which offers system resistance. The gas is then guided to the exit via outlet ducts.