#!/usr/bin/python3
# -*- coding: utf-8 -*-
'''Pychemqt, Chemical Engineering Process simulator
Copyright (C) 2009-2025, Juan José Gómez Romera <jjgomera@gmail.com>
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
**Fitting accesories K**
TODO
'''
from math import atan, exp, sqrt, sin, pi
from lib.unidades import Dimensionless
from lib.utilities import refDoc
__doi__ = {
1:
{"autor": "Crane",
"title": "Flow of Fluids Through Valves, Fittings, and Pipe",
"ref": "Crane CO, 1982",
"doi": ""},
# 2:
# {"autor": "",
# "title": "",
# "ref": "",
# "doi": ""},
}
# Crane, Flow-of-Fluids-Through-Valve Pag 107
[docs]
@refDoc(__doi__, [1])
def K_contraction_crane(D1, D2, tita=None, L=None):
r"""Returns loss coefficient for a pipe contraction as shown in [1]_, pag
A-26
If Θ < 45º:
.. math::
K = 0.8 \sin \frac{\theta}{2}\left(1 - \beta^2\right)
and for Θ > 45º:
.. math::
K = 0.5 \right(1 - \beta^2\left) \sqrt{\sin \frac{\theta}{2}}
Parameters
----------
D1 : float
Pipe diameter of entrance of contraction, [m]
D2 : float
Pipe diameter of the exit of contraction, [m]
tita : float, optional
Angle of contraction, [degrees]
L : float, optional
Length of the contraction, [m]
Notes
-----
For gradual contraction we can define with the angle of the contraction Θ
or with the length of contraction, L.
Returns
-------
K : float
Loss coefficient, [-]
"""
# Ratio between both diameters after and before conraction
beta = D2/D1
if L is not None:
if L == 0.0:
tita = 180
else:
tita = 360/pi*2.0*atan((D1-D2)/(2*L))
if tita < 45:
# Formula 1
K = 0.8*sin(tita*pi/360)*(1-beta**2)
else:
# Formula 2
K = 0.5*sqrt(sin(tita*pi/360))*(1.-beta**2)
return Dimensionless(K)
[docs]
@refDoc(__doi__, [1])
def K_enlargement_crane(D1, D2, tita=None, L=None):
r"""Returns loss coefficient for a pipe expansion as shown in [1]_, pag
A-26
If Θ < 45º:
.. math::
K = 2.6 \sin \frac{\theta}{2}\left(1 - \beta^2\right)
and for Θ > 45º:
.. math::
K = \right(1 - \beta^2\left)^2
Parameters
----------
D1 : float
Pipe diameter of entrance of contraction, [m]
D2 : float
Pipe diameter of the exit of contraction, [m]
tita : float, optional
Angle of contraction, [degrees]
L : float, optional
Length of the contraction, [m]
Notes
-----
For gradual contraction we can define with the angle of the contraction Θ
or with the length of contraction, L.
Returns
-------
K : float
Loss coefficient, [-]
"""
# Ratio between both diameters after and before conraction
beta = D1/D2
if L is not None:
if L == 0.0:
tita = 180
else:
tita = 360/pi*2.0*atan((D1-D2)/(2*L))
if tita < 45:
# Formula 3
K = 2.6*sin(tita*pi/360)*(1.-beta**2)**2
else:
# Formula 4
K = (1-beta**2)**2
return K
[docs]
def K_flush(rd):
"""Usando el ajuste exponencial de la tabla disponible"""
if rd <= 1e-4:
K = 0.5
elif rd >= 0.15:
K = 0.04
else:
K = 0.038756579558111+0.45581466480399*exp(-rd/0.041195038092995)
return K
[docs]
def K_MitreBend(tita):
"""Usando el ajuste gausiano de la tabla disponible"""
return -0.31591884532927+29830.477527796*sqrt(2/pi)/122.94894071438 * \
exp(-2*((tita-183.88854928482)/122.94894071438)**2)
[docs]
def K_longBend(rD):
if rD <= 1.2:
K = 20
elif rD <= 1.7:
K = 14
elif rD <= 3.5:
K = 12
elif rD <= 5:
K = 14
elif rD <= 7:
K = 17
elif rD <= 9:
K = 24
elif rD <= 11:
K = 30
elif rD <= 13:
K = 34
elif rD <= 15:
K = 38
elif rD <= 18:
K = 42
else:
K = 50
return K
[docs]
def Ft(D):
"""Función dependiente del diametro que sirve para definir las K de
valvulas y accesorios de tuberías D debe ser introducido en mm"""
if D <= 15:
ft = 0.027
elif D <= 20:
ft = 0.025
elif D <= 25:
ft = 0.023
elif D <= 32:
ft = 0.022
elif D <= 40:
ft = 0.021
elif D <= 50:
ft = 0.019
elif D <= 80:
ft = 0.018
elif D <= 100:
ft = 0.017
elif D <= 125:
ft = 0.016
elif D <= 150:
ft = 0.015
elif D <= 250:
ft = 0.014
elif D <= 400:
ft = 0.013
else:
ft = 0.012
return ft
if __name__ == "__main__":
print(K_contraction_crane(3, 2, tita=None, L=0))
print(K_contraction_crane(3, 2, tita=180))
print(K_flush(0.10))
