calculating flow

[theregoesthewindow]

Sorry for sounding like such a stupid noob but how do you calculate flow for a valve?

[saladtossser]

i dont think ggdt does that
if any1 can find a free 2d or 3d airflow simulator, that will be really helpful

[boilingleadbath]

Well, after searching around for a few hours around the time I wrote COM-P, I found nothing. However, I did learn this: most flow simulators are only available on request, at costs where a licence of a few hundred dollars a year is "cheap".

In the meantime, we are limmited to geussing at the valve flow, or working backwards using the GGDT...
sprinkler valves flow at about 33% of the valve orfice...

[theregoesthewindow]

could i approcimate(sp) flow by just saying the lowest cross-sctional area of the valve?

[boilingleadbath]

No, that doesn't really work - the other variables matter too much for that to make a good estimate all on it's own. Assuming your using the GGDT, I'd set the options so that you enter your valve flow as an efishency, which we can estimate rough values for. (it'll essentialy multiply the orfice size by the imput efishancy)

These efishency values largly dependent on the number of turns in the valve (fewer is better), wheather these turns are sharp, and things like that.

[theregoesthewindow]

ok thanx just wondering only used a ball valve and modded sprinkler before, i just wanted to see if i could determine the efficiency of a valve before building it, come to think of it i could have just used the ggdt and saved everyone a lot of time

Sorry!!!!