Math and or Fluid Flow Gurus. Spraybar hole calculations

[Jgray152]

So I can't seem to find any information on this at all.

Can't really use the common "area of a circle" math because it doesn't really work for diameters of 1" or smaller.

Basically, what size should 15 circles be that would equal a 1" diameter circle.

I couldn't figure it out with equations so I decided to use volume of flow and flow velocity online calculators to figure this out but I don't know if its correct.

I am trying to figure out a proper spray bar configuration for an Fx5 at 600 GPH.

So according to flow velocity and volume calculators, I would need 15 .258" holes to equal the flow velocity of a 1" hole at 600 GPH.

What I did was I calculated 600 GPH through a 1" diameter which equals 49 inches per second.
I then multiplied 49 by 15 which equaled 735 in/s. When I used that number in the calculator to figure a hole at 600 GPH, it came up with .258"

I don't know if this sounds right but I figure if yo uhave 49 in/s velocity through a 1" pipe, then you wan't that same velocity or less through a single hole to reduce in chances of increasing the output pressure. If you only used one small hole at .258", you would have a velocity of .735 in/sec at 600 GPH, problem is, that is VERY VERY VERY high pressure, a pressure we would never ever see so the flow rate would be substaintially lower, probubly around 100 gph if that. Depends on what pressure the Fx5 pump can produce.

So I figure have the same velocity through a small hole would mean you would need multiples of that same size hole, in this case, 15 holes.

Am I going about this wrong?

Then to make things more confusing, to keep equal pressures within the spray bar for a more equal distribution, I would need to have the spray bar tappered from from one end to the other to decrease the ID of the spray bar.

 

[PredatorTank215]

I was trying to figure out the same thing today when building my sump.

 

[Jgray152]

The way I was figuring it out is probably by far not the way to do it but its the closest I have come. I think the only way to figure this out is machining and testing different models and using meters such as volume flow meters and pressure gauges. As we know, the least amount of pressure attained increases the total flow volume output.

 

[FSM]

to get 15 holes with a total area the same to one 1" hole, you just need some simple math lol. Unless there is more to deal with since water is flowing through.

 

[dmopar74]

Then to make things more confusing, to keep equal pressures within the spray bar for a more equal distribution, I would need to have the spray bar tappered from from one end to the other to decrease the ID of the spray bar.

you can build a loop on your output and drill holes in the loop to get equal pressure to all holes.

 

[houie925]

1" hole=0.785 square inches(0.5*0.5*3.14)
0.785/15=0.052333(area of smaller hole)
0.052333/3.14=.016667(radius of smaller hole squared)
square root .016667=0.1291(radius of smaller hole)
0.1291*2=0.2582(diameter of smaller hole)
comes out the same with the calculator or the basic geometry
15 holes 0.258in each.
I second the loop idea

 

[svtim]

I like the loop ideal what size drill bit will you use and remember adding longer paths of tubing changes flow rate. so what will the spacing of the holes be in between them.

 

[Jgray152]

1" hole=0.785 square inches(0.5*0.5*3.14)
0.785/15=0.052333(area of smaller hole)
0.052333/3.14=.016667(radius of smaller hole squared)
square root .016667=0.1291(radius of smaller hole)
0.1291*2=0.2582(diameter of smaller hole)
comes out the same with the calculator or the basic geometry
15 holes 0.258in each.
I second the loop idea

You know, I did this too and for some reason it just didn't look right. I never did compair both results though. I probably would have had the same results as you if I would have just finished the equations.

What was throwing me off, even though I have figured this out before but this time I was stumped, maybe its because I only had a few hours of sleep, was the fact that I got .785 as an area and I kept thinking, "why is it less than 1 inch". lol Maybe becaue its a circle and not a sqaure!

you just need some simple math lol

The Embarrassment .....

 

[flstffxe]

Then to make things more confusing, to keep equal pressures within the spray bar for a more equal distribution, I would need to have the spray bar tappered from from one end to the other to decrease the ID of the spray bar.

Or just very the size of the holes. Smaller holes closer to the supply end of the bar larger holes at the dead end.

 

[svtim]

Im really liking this thread i so want to add a spray bar to my fx5 but haven't seen a design that i like yet but i like this one. keep up the numbers guys and post some pics if you build it.