Georg_Brantegger/Python-DT_Slot_3
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further code cleanup

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Brantegger Georg
2022-07-25 15:59:46 +02:00
parent 0de946f8ac
commit ac8bfdb7c6
9 changed files with 448 additions and 438 deletions
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165
Druckrohrleitung/Druckrohrleitung_class_file.py
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@@ -1,51 +1,40 @@
import numpy as np
#importing pressure conversion function
import sys
import os
current = os.path.dirname(os.path.realpath(__file__))
parent = os.path.dirname(current)
sys.path.append(parent)
from functions.pressure_conversion import pressure_conversion
class Druckrohrleitung_class:
# units
acceleration_unit = r'$\mathrm{m}/\mathrm{s}^2$'
angle_unit = 'rad'
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'
time_unit = 's'
velocity_unit = r'$\mathrm{m}/\mathrm{s}$' # for flux and pressure propagation
volume_unit = r'$\mathrm{m}^3$'
acceleration_unit = r'$\mathrm{m}/\mathrm{s}^2$'
angle_unit = 'rad'
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'$\mathrm{m}^3$'
acceleration_unit_print = 'm/s²'
angle_unit_print = 'rad'
area_unit_print = 'm²'
density_unit_print = 'kg/m³'
flux_unit_print = 'm³/s'
length_unit_print = 'm'
time_unit_print = 's'
velocity_unit_print = 'm/s' # for flux and pressure propagation
volume_unit_print = 'm³'
acceleration_unit_print = 'm/s²'
angle_unit_print = 'rad'
area_unit_print = 'm²'
density_unit_print = 'kg/m³'
flux_unit_print = 'm³/s'
length_unit_print = 'm'
time_unit_print = 's'
velocity_unit_print = 'm/s' # for flux and pressure propagation
volume_unit_print = 'm³'
# 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.rho = rho
self.g = g
self.length = total_length # total length of the pipeline
self.dia = diameter # diameter of the pipeline
self.n_seg = number_segments # number of segments for the method of characteristics
self.angle = pipeline_angle # angle of the pipeline
self.f_D = Darcy_friction_factor # = Rohrreibungszahl oder flow coefficient
self.density = rho # density of the liquid in the pipeline
self.g = g # gravitational acceleration
self.dx = total_length/number_segments
self.l_vec = np.arange(0,(number_segments+1)*self.dx,self.dx)
self.dx = total_length/number_segments # length of each segment
self.l_vec = np.arange(0,(number_segments+1),1)*self.dx # vector giving the distance from each node to the start of the pipeline
# initialize for get_info method
self.c = '--'
@@ -53,32 +42,32 @@ class Druckrohrleitung_class:
# setter
def set_pressure_propagation_velocity(self,c):
self.c = c
self.dt = self.dx/c
self.c = c # propagation velocity of the pressure wave
self.dt = self.dx/c # timestep derived from c, demanded by the method of characteristics
def set_number_of_timesteps(self,number_timesteps):
self.nt = number_timesteps
self.nt = number_timesteps # number of timesteps
if self.c == '--':
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,pressure_unit,display_pressure_unit):
if np.size(pressure) == 1:
def set_initial_pressure(self,pressure):
# initialize the pressure distribution in the pipeline
if np.size(pressure) == 1:
self.p0 = np.full_like(self.l_vec,pressure)
elif np.size(pressure) == np.size(self.l_vec):
self.p0 = pressure
else:
raise Exception('Unable to assign initial pressure. Input has to be of size 1 or' + np.size(self.l_vec))
self.pressure_unit = pressure_unit
self.pressure_unit_print = display_pressure_unit
#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 = np.empty_like(self.p_old)
self.p_old = self.p0.copy()
self.p = self.p0.copy()
def set_initial_flow_velocity(self,velocity):
if np.size(velocity) == 1:
# initialize the velocity distribution in the pipeline
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
@@ -86,35 +75,51 @@ class Druckrohrleitung_class:
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 = np.empty_like(self.v_old)
self.v_old = self.v0.copy()
self.v = self.v0.copy()
def set_boundary_conditions_next_timestep(self,v_reservoir,p_reservoir,v_turbine):
rho = self.rho
def set_boundary_conditions_next_timestep(self,p_reservoir,v_turbine):
# derived from the method of characteristics, one can set the boundary conditions for the pressures and flow velocities at the reservoir and the turbine
# the boundary velocity at the turbine is specified by the flux through the turbine or an external boundary condition
# the pressure at the turbine will be calculated using the forward characteristic
# the boundary pressure at the reservoir is specified by the level in the reservoir of an external boundary condition
# the velocity at the reservoir will be calculated using the backward characteristic
# constants for a cleaner formula
rho = self.density
c = self.c
f_D = self.f_D
dt = self.dt
D = self.dia
g = self.g
alpha = self.angle
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 # at new timestep
p_old_tur = self.p_old[-2] # @ second to last node (the one before the turbine)
v_old_tur = self.v_old[-2] # @ second to last node (the one before the turbine)
p_old_res = self.p_old[1] # @ second node (the one after the reservoir)
v_old_res = self.v_old[1] # @ second node (the one after the reservoir)
# set the boundary conditions derived from reservoir and turbine
self.v_boundary_tur = v_turbine # at new timestep
self.p_boundary_res = p_reservoir
self.p_boundary_tur = p_old-rho*c*(v_turbine-v_old)+rho*c*dt*g*np.sin(alpha)-f_D*rho*c*dt/(2*D)*abs(v_old)*v_old
self.p_boundary_res = p_reservoir # at new timestep
# calculate the missing boundary conditions
self.v_boundary_res = v_old_res+1/(rho*c)*(p_reservoir-p_old_res)+dt*g*np.sin(alpha)-f_D*dt/(2*D)*abs(v_old_res)*v_old_res
self.p_boundary_tur = p_old_tur-rho*c*(v_turbine-v_old_tur)+rho*c*dt*g*np.sin(alpha)-f_D*rho*c*dt/(2*D)*abs(v_old_tur)*v_old_tur
# write boundary conditions to the velocity/pressure vectors of the next timestep
self.v[0] = self.v_boundary_res.copy()
self.v[-1] = self.v_boundary_tur.copy()
self.p[0] = self.p_boundary_res.copy()
self.p[-1] = self.p_boundary_tur.copy()
def set_steady_state(self,ss_flux,ss_level_reservoir,pl_vec,h_vec,pressure_unit,display_pressure_unit):
def set_steady_state(self,ss_flux,ss_level_reservoir,pl_vec,h_vec):
# set the pressure and velocity distributions, that allow a constant flow of water from the (steady-state) reservoir to the (steady-state) turbine
# the flow velocity is given by the constant flow through the pipe
ss_v0 = np.full(self.n_seg+1,ss_flux/(self.dia**2/4*np.pi))
ss_pressure = (self.rho*self.g*(ss_level_reservoir+h_vec)-ss_v0**2*self.rho/2)-(self.f_D*pl_vec/self.dia*self.rho/2*ss_v0**2)
# the static pressure is given by the hydrostatic pressure, corrected for friction losses and dynamic pressure
ss_pressure = (self.density*self.g*(ss_level_reservoir+h_vec)-ss_v0**2*self.density/2)-(self.f_D*pl_vec/self.dia*self.density/2*ss_v0**2)
self.set_initial_flow_velocity(ss_v0)
self.set_initial_pressure(ss_pressure,pressure_unit,display_pressure_unit)
self.set_initial_pressure(ss_pressure)
# getter
def get_info(self):
@@ -142,30 +147,27 @@ class Druckrohrleitung_class:
f"Velocity and pressure distribution are vectors and are accessible by the .v and .p attribute of the pipeline object")
print(print_str)
def get_boundary_conditions_next_timestep(self):
print('The pressure at the reservoir for the next timestep is', '\n', \
pressure_conversion(self.p_boundary_res,self.pressure_unit,self.pressure_unit_print), '\n', \
'The velocity at the reservoir for the next timestep is', '\n', \
self.v_boundary_res, self.velocity_unit_print, '\n', \
'The pressure at the turbine for the next timestep is', '\n', \
pressure_conversion(self.p_boundary_tur,self.pressure_unit,self.pressure_unit_print), '\n', \
'The velocity at the turbine for the next timestep is', '\n', \
self.v_boundary_tur, self.velocity_unit_print)
def get_current_pressure_distribution(self):
return self.p
def get_current_velocity_distribution(self):
return self.v
def timestep_characteristic_method(self):
#number of nodes
nn = self.n_seg+1
rho = self.rho
c = self.c
f_D = self.f_D
dt = self.dt
D = self.dia
g = self.g
alpha = self.angle
# use the method of characteristics to calculate the pressure and velocities at all nodes except the boundary ones
# they are set with the .set_boundary_conditions_next_timestep() method beforehand
nn = self.n_seg+1 # number of nodes
rho = self.density # density of liquid
c = self.c # pressure propagation velocity
f_D = self.f_D # Darcy friction coefficient
dt = self.dt # timestep
D = self.dia # pipeline diametet
g = self.g # graviational acceleration
alpha = self.angle # pipeline angle
# Vectorize this loop?
for i in range(1,nn-1):
self.v[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]) \
+dt*g*np.sin(alpha)-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])
@@ -173,5 +175,8 @@ class Druckrohrleitung_class:
self.p[i] = 0.5*(self.p_old[i+1]+self.p_old[i-1]) - 0.5*rho*c*(self.v_old[i+1]-self.v_old[i-1]) \
+f_D*rho*c*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])
# prepare for next call
# use .copy() to write data to another memory location and avoid the usual python reference pointer
# else one can overwrite data by accidient and change two variables at once without noticing
self.p_old = self.p.copy()
self.v_old = self.v.copy()