def __init__(self,inlet,mdot):
import ammonia_props
amm = ammonia_props.AmmoniaProps()
self.inlet = inlet
self.mdot = mdot
liquid = amm.props2(P = inlet.P, x = inlet.x, Qu = 0)
vapor = amm.props2(P = inlet.P, x = inlet.x, Qu = 1)
if liquid.T == vapor.T:
pass
#q,T = self._q, self.T
# Determine what enthalpy to give at saturation temperature, since
# at saturation temperature, rounding depends whether
# the user intends heating or cooling.
if inlet.h < liquid.h:
self.h_sat = liquid.h
elif inlet.h > vapor.h:
self.h_sat = vapor.h
else:
self.h_sat = inlet.h
Tmin,Tmax = 200,400
minstate = amm.props2(P = inlet.P, x = inlet.x, T = Tmin)
maxstate = amm.props2(P = inlet.P, x = inlet.x, T = Tmax)
h_min,h_max = minstate.h, maxstate.h
q_points = []
T_points = []
for h in np.linspace(h_min, h_max):
q_points.append(mdot * (h - inlet.h))
state = amm.props2(P = inlet.P, x = inlet.x, h = h)
T_points.append(state.T)
self.q = scipy.interpolate.PchipInterpolator(T_points, q_points)
self.T = scipy.interpolate.PchipInterpolator(q_points, T_points)
def residualsAmmonia(T,P,x,deltaT=1e-4,deltaP=1e-4):
myprops = ammonia_props.AmmoniaProps()
f1 = myprops.props(123)
state1 = f1(T,P,x)
state2 = f1(T,P+deltaP,x)
state3 = f1(T+deltaT,P,x)
dhdp_T = (state2.h - state1.h) / deltaP
dvdT_p = (state3.v - state1.v) / deltaT
a = dhdp_T - (state1.v - T * dvdT_p)
cp = f1.massSpecificHeat(T=T, P=P, x=x)
dhdT_p = (state3.h - state1.h) / deltaT
b = dhdT_p - cp
print(state1)
print(state2)
print(state3)
print("a = {}. b = {}".format(a,b))
return a,b
# -*- coding: utf-8 -*-
"""
Created on Wed Feb 18 14:42:55 2015
@author: nfette
"""
from __future__ import print_function
import ammonia_props
from hw2_1 import CelsiusToKelvin as C2K
if __name__ == "__main__":
print("(a) Mixture properties from TPx:")
myprops = ammonia_props.AmmoniaProps()
f1 = myprops.props('TPx')
T, P, x = C2K(50.), 10., 0.0 # K, bar, dim
state = f1(T, P, x)
print(state)
print(f1.getOutputUnits())
print("(b) ... in molar units:")
Meff = state.molarMass()
hbar = state.h * Meff
print("Meff = {} kg/kmol".format(Meff))
print("hbar = {} kJ/kmol".format(hbar))
print("(c) Partial component enthalpies")
dhdx = f1.dhdxetc(T=T, P=P, x=x)
print("{} kJ/kg".format(dhdx))
print("(d) Enthalpy of mixing")
x = state.x
import numpy
import matplotlib.pyplot as plt
import ammonia_props
amm = ammonia_props.AmmoniaProps()
P0 = 1.0
x_range = numpy.linspace(0, 1, 101)
p_min = numpy.empty_like(x_range)
p_min.fill(numpy.nan)
t_out = p_min.copy()
for i, x in enumerate(x_range):
try:
P = P0
for j in range(20):
state = amm.props2(x=x, P=P, Qu=0)
P *= 0.8
except:
pass
p_min[i] = P
t_out[i] = state.T
plt.figure()
plt.plot(x_range, p_min)
plt.figure()
plt.plot(x_range, t_out)
plt.show()