Water spray bar design. 2

[Elayek]

I am trying to design a water spray bar. I am going to use a 1" SS pipe that is 57" long and I am mounting 12 1/4" SS valves then misting nozzels (1.5 GPH each) to the valves.

My original plan was to feed the spray bar with a 1/2" SS pipe right from the center. but I am having a second thought about that and I am thinking of feeding from both ends to avoid turbulant flow and pressure reduction at the center of the spray bar. I am not sure which way to go.

Any help with that will be appreciated. please explain why which way is better than the other.

Water pressure is 40PSI, Total flow rate should be around 18GPH, water is 120 degrees.

Thanks,

 

[Zapster]

Your fluid velocity is low enough that I question your concern? It looks like your fluid velocity will be less than 1/2 ft/sec for the smaller pipe size and 1/10 ft/sec for the 1" pipe. Assumed sch 80.

 

[Ron]

Since they are misting nozzles, I wouldn't worry too much about it. Assuming typical water pressure greater than 30 psi, the output is only 18 gph, whereas your input could easily be 5 to 10 times that amount....so always plenty of water to supply the output, remaining under pressure since the head loss through a misting nozzle is high.

We use spray bars for window and wall testing. Our output per nozzle is quite a bit higher than yours (5.0 gal/ft^2/hour or about 11 gal/hour for typical nozzle spacing), and we sometimes have to balance the nozzles, even though our spray racks are looped with water coming at the nozzles from at least two "directions".

 

[Elayek]

Thank you guys for your help.
These answers cleared a lot of things.