simple calculation of pipe diameter
Posted: Sat May 29, 2010 1:34 pm
Hi dear society,
I need your help in very simple calculation, which unfortunately, I cannot perform properly.
I need to calculate a diameter of ideal (no friction) pipe, filled for 100% (so that hydraulic D = D of the pipe)
My capacity (Q) is 10 c.m./hr
Fluid is water at +50ºC
The Re numbers must be 2200 and 15000.
I have used the following equation:
..........Re*(μ/ρ)*A........Re*(μ/ρ)*(πD²/4)
D(m) = ---------------- = -----------------------;
...............Q......................Q
..............4*Q*1000
D(mm) = ----------------
.............Re*(μ/ρ)*π
But I get a very strange results:
= (4*1000*(10/3600))/(2300*(0,0005471/988,1)*3,14) = 2905 mm
= (4*1000*(10/3600))/(15000*(0,0005471/988,1)*3,14) = 426 mm
It means, that to receive a laminar water flow at 10 c.m./hr I need a pipe of almost 3m in diameter !
In the mean time I know for sure that the pipe DN65 will be more than enough.
So my calculation is completely incorrect !
Pls. anybody help me !
I need this calculation badly !
Thank you very much in advance !
I need your help in very simple calculation, which unfortunately, I cannot perform properly.
I need to calculate a diameter of ideal (no friction) pipe, filled for 100% (so that hydraulic D = D of the pipe)
My capacity (Q) is 10 c.m./hr
Fluid is water at +50ºC
The Re numbers must be 2200 and 15000.
I have used the following equation:
..........Re*(μ/ρ)*A........Re*(μ/ρ)*(πD²/4)
D(m) = ---------------- = -----------------------;
...............Q......................Q
..............4*Q*1000
D(mm) = ----------------
.............Re*(μ/ρ)*π
But I get a very strange results:
= (4*1000*(10/3600))/(2300*(0,0005471/988,1)*3,14) = 2905 mm
= (4*1000*(10/3600))/(15000*(0,0005471/988,1)*3,14) = 426 mm
It means, that to receive a laminar water flow at 10 c.m./hr I need a pipe of almost 3m in diameter !
In the mean time I know for sure that the pipe DN65 will be more than enough.
So my calculation is completely incorrect !
Pls. anybody help me !
I need this calculation badly !
Thank you very much in advance !