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added Druckrohrleitungs class, based on ETH Code

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Brantegger Georg
2022-06-29 13:51:53 +02:00
parent 57cb951f5b
commit 8cfd14838c
7 changed files with 401 additions and 16 deletions
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Druckrohrleitung/Druckrohrleitung_class_file.py Normal file
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from pressure_conversion import pressure_conversion
import numpy as np
class Druckrohrleitung_class:
# units
acceleration_unit = r'$\mathrm{m}/\mathrm{s}^2$'
angle_unit = '°'
area_unit = r'$\mathrm{m}^2$'
density_unit = r'$\mathrm{kg}/\mathrm{m}^3$'
flux_unit = r'$\mathrm{m}^3/\mathrm{s}$'
length_unit = 'm'
pressure_unit = 'Pa'
time_unit = 's'
velocity_unit = r'$\mathrm{m}/\mathrm{s}$' # for flux and pressure propagation
volume_unit = r'$\mathrm{m}^3$'
# init
def __init__(self,total_length,diameter,number_segments,pipeline_angle,Darcy_friction_factor,rho=1000,g=9.81):
self.length = total_length
self.dia = diameter
self.n_seg = number_segments
self.angle = pipeline_angle
self.f_D = Darcy_friction_factor # = Rohrreibungszahl oder flow coefficient
self.density = 1000
self.g = g
self.dx = total_length/number_segments
self.l_vec = np.arange(0,(number_segments+1)*self.dx,self.dx)
# workaround for try-except construct in set_number_of_timesteps
self.c = 0
# setter
def set_pressure_propagation_velocity(self,c):
self.c = c
self.dt = self.dx/c
def set_number_of_timesteps(self,number_timesteps):
self.nt = number_timesteps
if self.c == 0:
raise Exception('Please set the pressure propagation velocity before setting the number of timesteps.')
else:
self.t_vec = np.arange(0,self.nt*self.dt,self.dt)
def set_initial_pressure(self,pressure,input_unit = 'Pa'):
p,_ = pressure_conversion(pressure,input_unit,target_unit=self.pressure_unit)
if np.size(p) == 1:
self.p0 = np.full_like(self.l_vec,p)
elif np.size(p) == np.size(self.l_vec):
self.p0 = p
else:
raise Exception('Unable to assign initial pressure. Input has to be of size 1 or' + np.size(self.l_vec))
#initialize the vectors in which the old and new pressures are stored for the method of characteristics
self.p_old = self.p0.copy()
self.p_new = np.empty_like(self.p_old)
def set_initial_flow_velocity(self,velocity):
if np.size(velocity) == 1:
self.v0 = np.full_like(self.l_vec,velocity)
elif np.size(velocity) == np.size(self.l_vec):
self.v0 = velocity
else:
raise Exception('Unable to assign initial velocity. Input has to be of size 1 or' + np.size(self.l_vec))
#initialize the vectors in which the old and new velocities are stored for the method of characteristics
self.v_old = self.v0.copy()
self.v_new = np.empty_like(self.v_old)
def set_boundary_conditions_next_timestep(self,v_reservoir,p_reservoir,v_turbine,input_unit_pressure = 'Pa'):
rho = self.density
c = self.c
f_D = self.f_D
dt = self.dt
D = self.dia
p_old = self.p_old[-2] # @ second to last node (the one before the turbine)
v_old = self.v_old[-2] # @ second to last node (the one before the turbine)
self.v_boundary_res = v_reservoir
self.v_boundary_tur = v_turbine
self.p_boundary_res,_ = pressure_conversion(p_reservoir,input_unit_pressure,target_unit=self.pressure_unit)
self.p_boundary_tur = p_old+rho*c*v_old-rho*c*f_D*dt/(2*D)*abs(v_old)*v_old
self.v_new[0] = self.v_boundary_res.copy()
self.v_new[-1] = self.v_boundary_tur.copy()
self.p_new[0] = self.p_boundary_res.copy()
self.p_new[-1] = self.p_boundary_tur.copy()
# getter
def get_pipeline_geometry(self):
print('The total length of the pipeline is', '\n', \
self.length, self.length_unit, '\n', \
'The diameter of the pipeline is', '\n', \
self.dia, self.length_unit, '\n', \
'The pipeline is divided into', self.n_seg , 'segments of length', '\n', \
round(self.dx,1), self.length_unit, '\n', \
'The pipeline has an inclination angle of', '\n', \
self.angle, self.angle_unit)
def get_other_pipeline_info(self):
print('The Darcy-friction factor of the pipeline is', '\n', \
self.f_D, '\n', \
'The pipeline is filled with a liquid with density', '\n', \
self.density, self.density_unit, '\n', \
'The gravitational acceleration is set to', '\n', \
self.g, self.acceleration_unit)
def get_pressure_propagation_velocity(self):
print('The pressure propagation velocity in the pipeline is', '\n', \
self.c, self.velocity_unit)
def get_number_of_timesteps(self):
print(self.nt, 'timesteps are performed in the simulation')
def get_initial_pressure(self,target_unit='bar'):
print('The inital pressure distribution in is', '\n', \
pressure_conversion(self.p0,self.pressure_unit,target_unit))
def get_initial_flow_velocity(self):
print('The inital velocity distribution is', '\n', \
self.v0, self.velocity_unit)
def get_boundary_conditions_next_timestep(self,target_unit_pressure ='bar'):
print('The pressure at the reservoir for the next timestep is', '\n', \
pressure_conversion(self.p_boundary_res,self.pressure_unit,target_unit_pressure), '\n', \
'The velocity at the reservoir for the next timestep is', '\n', \
self.v_boundary_res, self.velocity_unit, '\n', \
'The pressure at the turbine for the next timestep is', '\n', \
pressure_conversion(self.p_boundary_tur,self.pressure_unit,target_unit_pressure), '\n', \
'The velocity at the turbine for the next timestep is', '\n', \
self.v_boundary_tur, self.velocity_unit)
def timestep_characteristic_method(self):
#number of nodes
nn = self.n_seg+1
rho = self.density
c = self.c
f_D = self.f_D
dt = self.dt
D = self.dia
for i in range(1,nn-1):
self.v_new[i] = 0.5*(self.v_old[i-1]+self.v_old[i+1])+0.5/(rho*c)*(self.p_old[i-1]-self.p_old[i+1]) \
-f_D*dt/(4*D)*(abs(self.v_old[i-1])*self.v_old[i-1]+abs(self.v_old[i+1])*self.v_old[i+1])
self.p_new[i] = 0.5*rho*c*(self.v_old[i-1]-self.v_old[i+1])+0.5*(self.p_old[i-1]+self.p_old[i+1]) \
-rho*c*f_D*dt/(4*D)*(abs(self.v_old[i-1])*self.v_old[i-1]-abs(self.v_old[i+1])*self.v_old[i+1])
self.p_old = self.p_new.copy()
self.v_old = self.v_new.copy()