# 7.2 L, L over D and K from Kv for Conventional Type Valves

A 150 mm class 125 Y-pattern globe valve with a Kv=500 flow coefficient is given.

Calculate the resistance coefficient K, L/D equivalent, and the length for complete turbulence in the flow.

Use schedule 40, 150 mm pipe as a reference.

    [1]:

    from fluids.units import *
    D = .154*u.m
    Kv = 500*u.m**3/u.hour

    K = Kv_to_K(Kv, D)
    L_D = L_equiv_from_K(K, fd=.015)
    L = D*L_D

    print('Loss coefficient = %s' %K)
    print('Equivalent length = %s' % L_D)
    print('Length for complete turbulence = %s' %L)

    Loss coefficient = 3.5996713984 dimensionless
    Equivalent length = 239.978093227 dimensionless
    Length for complete turbulence = 36.9566263569 meter

The results calculated in Crane TP 410M are 3.6, 240, and 37.0 respectively.