[gary2506]

I am fairly new to CFD, I have a lot of experience with Inventor. My problem is with a HVAC simulation, I have some duct work with a blower in it, and surrounding airspace. every thing runs fine. I would like to run the design with te blower off and get the airspace into a converged state, then turn the blower on and let it run until it get to a converged state with the blower on. I have done similar design study's using velocity, but I am trying to run it using a centrifugal blower as a material.

Edit:
I should probably let you know what I have tried so far, If I set the materiel setting to 0 CFM and 0 rotation, it doesn't seem to restart when change them back to actual numbers. If I suppress the material, then when I resume it, a re-mesh is required and I lose my previous iterations. turning flow off and on doesn't solve my problem either, since this study uses temperature, humidity and convection to produce a flow within the airspace. I require the temperature distribution and velocity in my results.

[ApoloV]

gary,
If you are doing humidity within the blower, be careful as all simplified materials (blowers/fans/resistances) use an averaged property and this average can introduce offset from what you might be expecting for the solution.

IF the model is a steadystate run, is there a particular reason you want without the blower and then with it?
As far as having it turn off/on, one method at times is to assign the volume as part of the fluid, then run the model. Once that runs out, you can always clone and try to add the blower back in rather than changing its flowrate.

If this is a transient model, you could use a Thermostat and specify a face where you know that the temperature will cross a specific value when you want it to turn on (this method could be used in steadystate as well to some extent)

[gary2506]

ApoloV

Thanks for the idea. I use moist variable air and have 2 rooms of airspace with different temperatures and humidity's in each room, I set the temp and humidity using boundary conditions then run solve until the rooms converge into a stabel condition, then I want to turn on my equipment and see how it affects the doorway and the rooms by running solve again from the previous last.

I think I can make it work with a thermostat, I guess I hadnt thought of that before but the real equipment does use a thermostat so, duh, I don't know why I didn't think of that before.

In the second idea you presented you are saying to change the blower volume to a fluid (variable air in my case) and change it back to blower when I want to turn it on. that might also be a working solution.

thanks for the ideas, now I have to run more tests