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Ceiling fan simluation questions

Question asked by Logan Vaught on Feb 19, 2015
Latest reply on Mar 9, 2015 by Jared Conway

Hello,

I want to first apologize if these questions have been asked before but I didnt see any when browsing.  This is for a senior engineering design class where our group is tasked with designing fan blades for a company that are efficient.  What I am trying to do is recreate the Energy Star test for ceiling fans in Solidworks(picture included of test below).  I have a model of a known fan from the company I am working with, but I have a few questions on how to set this up more correctly than I have.  I have a basic understanding of how to do these simulations and have run a few, but my simulations seem off.  I have been reading a ton into this but I would like to get some insight from you all and see what is possible, necessary, or what I may be missing.

Energystartest.jpg

 

Test so far -

I have based my testing method is based on a series of youtube videos showing a fan simulation in an enclosure. (https://www.youtube.com/watch?v=xvZgyJ2V-bE)  This is the first of the videos for this simulation.  However my set up with the fan, cylinder, and enclosure are different(like a fan rotating about the y axis vs his on the x) but the concepts remain the same.

 

Fantest1.jpg

 

So far the flow rate is low compared to the listed values and drops off entirely at lower rpm.  The fan is listed at 5400CFM at 178 rpm but I get closer to 4000CFM.  For the project I wouldnt need to get exactly 5400 for a fan like this, but it would be nice to have a closer value therefore we can be a little more sure our designed fans are performing as expected. 

 

 

 

Simulation Questions

  1. Meshing – What settings are most important for this?  I have been using simple settings at first for faster calculation just to figure out how to get things running and then will crank up the refinement, if needed, when I run my final simulations.
  2. Goals – Surface of each bit of the fan blades or volume goal based on rotating domain cylinder
  3. Set-up – Is this possible or accurate?  Internal or external?  What separate settings
  4. Boundary conditions – When using the enclosure I have them set at the standard atm pres
  5. With my cylinder that is set up like the physical test, do I need to define anything associated with it like a boundary layer or separate fluid domain?  Ive  seen that this type of external/internal stuff can be difficult so any suggestions as to recreate this test or make something similar would be very appreciated.
  6. Calculation options - Any specific settings to change to my analysis goes long enough to measure steady state flow or at least the airflow after it has been going for a minute or two?

 

Any other advice would be greatly appreciated. 

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