Pressure drop across an array of different nozzles?

tectactoe

I have a question about calculating the pressure drop in a large flow meter across an array of nozzles. Basically its inside of a tunnel... air flows in this tunnel until it reaches a "gate" which is blocked off except for six nozzles of different size, which discharge back into an open tunnel...

We know the velocity of the air before the nozzle array (5 m/s), the diameter of the flow meter tunnel (50"), as well as the exit diameter of the six nozzles (6", 3 x 4", 3", and 2").

To be honest, I'm not sure what to do when it comes to the parallel pressure drop through different nozzles. I tried Bernoulli's equation using the total combined exit diameter of the nozzles as my exit point.... It gave me about 1.22 inH2O. But I feel like this calculation is wrong because you can not just add up the nozzle exit diameters when in parallel.

Any suggestions?

tectactoe

anyone? any insight would be greatly appreciated.

mender

The HVAC guys might have something about that for their long furnace duct runs.