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small changes for consistency, comments and a small fix in the convergence method of the turbine

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Brantegger Georg
2022-08-08 14:49:22 +02:00
parent 5a790d5ca5
commit 38c809ef49
10 changed files with 496 additions and 304 deletions
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48
Turbinen/Turbinen_class_file.py
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@@ -11,8 +11,8 @@ sys.path.append(parent)
from functions.pressure_conversion import pressure_conversion
class Francis_Turbine:
# units
# make sure that units and print units are the same
# units
# make sure that units and display units are the same
# units are used to label graphs and disp units are used to have a bearable format when using pythons print()
density_unit = r'$\mathrm{kg}/\mathrm{m}^3$'
flux_unit = r'$\mathrm{m}^3/\mathrm{s}$'
@@ -32,7 +32,16 @@ class Francis_Turbine:
g = 9.81 # m/s² gravitational acceleration
# init
def __init__(self, Q_nenn,p_nenn,t_closing,timestep,pressure_unit_disp):
def __init__(self,Q_nenn,p_nenn,t_closing,timestep,pressure_unit_disp):
"""
Creates a turbine with given attributes in this order: \n
Nominal flux [m³/s] \n
Nominal pressure [Pa] \n
Closing time [s] \n
Simulation timestep [s] \n
Pressure unit for displaying [string] \n
"""
self.Q_n = Q_nenn # nominal flux
self.p_n = p_nenn # nominal pressure
self.LA_n = 1. # 100% # nominal Leitapparatöffnung
@@ -42,21 +51,21 @@ class Francis_Turbine:
self.pressure_unit_disp = pressure_unit_disp
# initialize for get_info() - parameters will be converted to display -1 if not overwritten
self.p = pressure_conversion(-1,self.pressure_unit_disp,self.pressure_unit)
self.Q = -1.
self.LA = -0.01
# initialize for get_info()
self.p = -np.inf
self.Q = -np.inf
self.LA = -np.inf
# setter
# setter - set attributes
def set_LA(self,LA,display_warning=True):
# set Leitapparatöffnung
self.LA = LA
# warn user, that the .set_LA() method should not be used ot set LA manually
if display_warning == True:
print('You are setting the guide vane opening of the turbine manually. \n \
This is not an intended use of this method. \n \
Refer to the .update_LA() method instead.')
# set Leitapparatöffnung
self.LA = LA
def set_pressure(self,pressure):
# set pressure in front of the turbine
@@ -70,7 +79,7 @@ class Francis_Turbine:
raise Exception('LA out of range [0;1]')
self.set_LA(ss_LA,display_warning=False)
#getter
#getter - get attributes
def get_current_Q(self):
# return the flux through the turbine, based on the current pressure in front
# of the turbine and the Leitapparatöffnung
@@ -83,8 +92,11 @@ class Francis_Turbine:
def get_current_LA(self):
return self.LA
def get_current_pressure(self):
return pressure_conversion(self.p,self.pressure_unit,self.pressure_unit_disp)
def get_current_pressure(self,disp_flag=True):
if disp_flag == True:
return pressure_conversion(self.p,self.pressure_unit,self.pressure_unit_disp)
else:
return self.p
def get_info(self, full = False):
new_line = '\n'
@@ -135,7 +147,9 @@ class Francis_Turbine:
# methods
def converge(self,convergence_parameters):
# small numerical disturbances (~1e-12 m/s) in the velocity can get amplified at the turbine node, because the new velocity of the turbine and the
# new pressure from the forward characteristic are not compatible.
# new pressure from the forward characteristic are not perfectly compatible.
# Therefore, iterate the flux and the pressure so long, until they converge
eps = 1e-12 # convergence criterion: iteration change < eps
iteration_change = 1. # change in Q from one iteration to the next
i = 0 # safety variable. break loop if it exceeds 1e6 iterations
@@ -150,20 +164,18 @@ class Francis_Turbine:
rho = convergence_parameters[7] # density of the liquid
dt = convergence_parameters[8] # timestep of the characteristic method
p_old = self.get_current_pressure()
Q_old = self.get_current_Q()
v_old = Q_old/area_pipe
while iteration_change > eps:
self.set_pressure(p_old)
p_new = p-rho*c*(v_old-v)+rho*c*dt*g*np.sin(alpha)-f_D*rho*c*dt/(2*D)*abs(v)*v
self.set_pressure(p_new)
Q_new = self.get_current_Q()
v_new = Q_new/area_pipe
p_new = p-rho*c*(v_old-v)+rho*c*dt*g*np.sin(alpha)-f_D*rho*c*dt/(2*D)*abs(v)*v
iteration_change = abs(Q_old-Q_new)
Q_old = Q_new.copy()
p_old = p_new.copy()
v_old = v_new.copy()
i = i+1
if i == 1e6: