Air pressure and velocity in a pipe

[confused slug]

This is NOT homework. The fan is a Crary Fan and the hose is Oregon PU used to distribute particles. I have tried a number of 'online' calculation sites but they return either conflicting results or 'infinite' values!


Dear All

I am trying to determine / estimate the expected air velocity and pressure at the end of a 5m long hose, supplied by a centrifugal fan coupled directly onto the hose. The information / assumptions i have are;

Fan System
Static Pressure: 4kPa
Volumetric Flow: 40m3/min

Pipe
Length: 5m
Diameter: 110mm
Roughness: 0.05mm
Minor Loss Coef: 0.1

Air
Temp: 15°c
Density: 1.1 kg/m3
Kinematic Viscosity: 10 E-6 m2/s


From this is it possible to estimate the velocity of the air stream at the start of the hose and at the and (v1 & v2) and the associated pressures (p1 & p2)? If it is ,what are the calculations?

I assume that due to the resistance caused by the pipe there will exist a 'back pressure' in the pipe. What would this pressure be 1m from the fan outlet (1m down the pipe).


Thanks
Confused

 

[Chestermiller]

This flow can be quantified using the Darcy-Weisbach friction factor vs Reynold number correlation. It may be necessary to take into account compressibility if the fluid is a gas, in which case one would be solving for the pressure squared rather than the pressure to the first power.