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 = '°' 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 = '°' area_unit_print = 'm²' density_unit_print = 'kg/m³' flux_unit_print = 'm³/s' length_unit_print = 'm' pressure_unit_print = 'Pa' 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.density = 1000 self.g = g self.dx = total_length/number_segments self.l_vec = np.arange(0,(number_segments+1)*self.dx,self.dx) # initialize for get_info method self.c = '--' self.dt = '--' # 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 == '--': 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 = 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 = 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[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() # getter def get_info(self): new_line = '\n' # :<10 pads the self.value to be 10 characters wide print_str = (f"The pipeline has the following attributes: {new_line}" f"----------------------------- {new_line}" f"Length = {self.length:<10} {self.length_unit_print} {new_line}" f"Diameter = {self.dia:<10} {self.length_unit_print} {new_line}" f"Number of segemnts = {self.n_seg:<10} {new_line}" f"Number of nodes = {self.n_seg+1:<10} {new_line}" f"Length per segment = {self.dx:<10} {self.length_unit_print} {new_line}" f"Pipeline angle = {self.angle:<10} {self.angle_unit_print} {new_line}" f"Darcy friction factor = {self.f_D:<10} {new_line}" f"Density of liquid = {self.density:<10} {self.density_unit_print} {new_line}" f"Pressure wave vel. = {self.c:<10} {self.velocity_unit_print} {new_line}" f"Simulation timesteps = {self.dt:<10} {self.time_unit_print } {new_line}" f"Number of timesteps = {self.nt:<10} {new_line}" f"----------------------------- {new_line}" 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,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_print,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_print,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[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[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.copy() self.v_old = self.v.copy()