# 7.1 Smooth Pipe (Plastic)

Water at 30 degrees Celsius flows through a 20 m length of 50 mm plastic (smooth wall) pipe, at a flow rate of 200 L/min.

Calculate the Reynolds number and friction factor.

    [1]:

    from fluids.units import  *
    from thermo.units import Stream
    from math import *

    Q = 0.2*u.m**3/u.min
    T = 30*u.degC
    P = 2*u.bar # assumed
    water = Stream('water', T=T, P=P, Q=Q)

    NPS, Di, Do, t = nearest_pipe(Di=0.05*u.m)
    v = Q/(pi/4*Di**2)
    Re = Reynolds(D=Di, rho=water.rho, mu=water.mu, V=v)
    print('Reynolds number = %s' %Re)
    fd = friction_factor(Re=Re, eD=_roughness['Glass']/Di)
    print('Darcy friction factor = %s' %fd)

    Reynolds number = 101004.75134699857 dimensionless
    Darcy friction factor = 0.01810866701300492 dimensionless

The values presented in their solution are Re=100600; and fd=0.0179. The difference in values is due to the precision they used.