def _Superheat_Forward(self, w_superheat):
self.w_superheat = w_superheat
DWS = DWSVals() #DryWetSegment structure
AS = self.AS #AbstractState
# Store temporary values to be passed to DryWetSegment
DWS.A_a = self.Fins.A_a * w_superheat
DWS.cp_da = self.Fins.cp_da
DWS.eta_a = self.Fins.eta_a
DWS.h_a = self.Fins.h_a * self.h_a_tuning #Heat transfer coefficient
DWS.mdot_da = self.mdot_da * w_superheat
DWS.pin_a = self.Fins.Air.p
DWS.Fins = self.Fins
DWS.FinsType = self.FinsType
# Inputs on the air side to two phase region are inlet air again
DWS.Tin_a = self.Tin_a
DWS.RHin_a = self.Fins.Air.RH
DWS.Tin_r = self.Tdew_r
DWS.A_r = self.A_r_wetted * w_superheat
DWS.Rw = self.Rw / w_superheat
AS.update(CP.PT_INPUTS, self.psat_r, self.Tdew_r + 2.5)
DWS.cp_r = AS.cpmass(
) #Use a guess value of 6K superheat to calculate cp [J/kg-K]
DWS.pin_r = self.psat_r
DWS.mdot_r = self.mdot_r
DWS.IsTwoPhase = False
#Use a guess value of 6K superheat to calculate the properties
self.f_r_superheat, self.h_r_superheat, self.Re_r_superheat = f_h_1phase_Tube(
self.mdot_r / self.Ncircuits, self.ID, self.Tdew_r + 3,
self.psat_r, self.AS, "Single")
# Average Refrigerant heat transfer coefficient
DWS.h_r = self.h_r_superheat
#Run DryWetSegment
DryWetSegment(DWS)
AS.update(CP.PT_INPUTS, self.psat_r, (DWS.Tout_r + self.Tdew_r) / 2.0)
rho_superheat = AS.rhomass() #[kg/m^3]
self.Charge_superheat = w_superheat * self.V_r * rho_superheat
#Pressure drop calculations for superheated refrigerant
v_r = 1 / rho_superheat
#Pressure gradient using Darcy friction factor
dpdz_r = -self.f_r_superheat * v_r * self.G_r**2 / (
2 * self.ID) #Pressure gradient
self.DP_r_superheat = dpdz_r * self.Lcircuit * self.w_superheat
#Set values
self.Q_superheat = DWS.Q
self.Q_sensible_superheat = DWS.Q_sensible
self.fdry_superheat = DWS.f_dry
self.Tout_a_superheat = DWS.Tout_a
self.Tout_r = DWS.Tout_r
def Calculate(self):
"""
This function is now simply a wrapper around the DryWetSegment()
function in order to decrease the amount of code replication
"""
#Initialize
self.Initialize()
AS_g = self.AS_g
DWS=DWSVals() #DryWetSegment structure
# Store temporary values to be passed to DryWetSegment
DWS.A_a=self.Fins.A_a
DWS.cp_da=self.Fins.cp_da
DWS.eta_a=self.Fins.eta_a
DWS.h_a=self.Fins.h_a*self.h_a_tuning #Heat transfer coefficient
DWS.mdot_da=self.Fins.mdot_da
DWS.pin_a=self.Fins.Air.p
DWS.Tin_a=self.Tin_a
DWS.RHin_a=self.Fins.Air.RH
DWS.Fins=self.Fins
DWS.FinsType=self.FinsType #Added to pass FinsType to DryWetSegment
DWS.Tin_r=self.Tin_g
DWS.A_r=self.A_g_wetted
DWS.Rw=self.Rw
AS_g.update(CP.PT_INPUTS, self.pin_g, (self.Tin_g+DWS.Tin_a)/2.0)
DWS.cp_r=AS_g.cpmass() #[J/kg-K]
DWS.pin_r=self.pin_g
DWS.mdot_r=self.mdot_g
DWS.IsTwoPhase=False
#Use a guess value of 6K superheat to calculate the properties
self.f_g, self.h_g, self.Re_g=f_h_1phase_Tube(self.mdot_g / self.Ncircuits, self.ID,
(self.Tin_g+DWS.Tin_a)/2.0, self.pin_g, self.AS_g, "Single");
# Average Refrigerant heat transfer coefficient
DWS.h_r=self.h_g*self.h_g_tuning
#Run DryWetSegment
DryWetSegment(DWS)
#Average mass flux of glycol in circuit
self.G_g = self.mdot_g/(self.Ncircuits*pi*self.ID**2/4.0) #[kg/m^2-s]
#Pressure drop calculations for glycol (water)
Dh_g=self.ID
AS_g.update(CP.PT_INPUTS, self.pin_g, self.Tin_g)
v_g=1/AS_g.rhomass() #[m^3/kg]
#Pressure gradient using Darcy friction factor
dp_dz_g=-self.f_g*v_g*self.G_g**2/(2*Dh_g)
DP_g=dp_dz_g*self.Lcircuit
self.f_dry=DWS.f_dry
self.DP_g=DP_g*self.DP_tuning
self.Q=DWS.Q
self.Tout_g=DWS.Tout_r
self.Tout_a=DWS.Tout_a
self.hout_a=DWS.hout_a
self.hin_a=DWS.hin_a
self.SHR=self.Fins.cp_da*(DWS.Tout_a-DWS.Tin_a)/(DWS.hout_a-DWS.hin_a)
self.Capacity=DWS.Q-self.Fins.Air.FanPower
def _Subcool_Forward(self, w_subcool):
# **********************************************************************
# SUPERCRITICAL_LIQUID PART
# **********************************************************************
self.w_subcool = w_subcool
if self.w_subcool < 0:
raise ValueError(
'w_subcool in Gas cooler cannot be less than zero')
#AbstractState
AS = self.AS
DWS = DWSVals() #DryWetSegment structure
# Store temporary values to be passed to DryWetSegment
DWS.A_a = self.Fins.A_a * w_subcool
DWS.cp_da = self.Fins.cp_da
DWS.eta_a = self.Fins.eta_a
DWS.h_a = self.Fins.h_a #Heat transfer coefficient
DWS.mdot_da = self.mdot_da * w_subcool
DWS.pin_a = self.Fins.Air.p
DWS.Fins = self.Fins
DWS.FinsType = self.FinsType
# Inputs on the air side to two phase region are inlet air again
DWS.Tin_a = self.Tin_a
DWS.RHin_a = self.Fins.Air.RH
DWS.Tin_r = self.Tcr
DWS.A_r = self.A_r_wetted * w_subcool
AS.update(CP.PT_INPUTS, self.psat_r, self.Tcr - 1)
DWS.cp_r = AS.cpmass() #[J/kg-K]
DWS.pin_r = self.psat_r
DWS.mdot_r = self.mdot_r
DWS.IsTwoPhase = False
# Friction factor and HTC in the refrigerant portions.
# Average fluid temps are used for the calculation of properties
# Average temp of refrigerant is average of sat. temp and outlet temp
# Secondary fluid is air over the fins
self.f_r_subcool, self.h_r_subcool, self.Re_r_subcool = f_h_1phase_Tube(
self.mdot_r / self.Ncircuits, self.ID, self.Tcr - 1.0, self.psat_r,
self.AS, "Single")
# Average Refrigerant heat transfer coefficient
DWS.h_r = self.h_r_subcool
#Run DryWetSegment
DryWetSegment(DWS)
AS.update(CP.PT_INPUTS, self.psat_r, (self.Tcr + DWS.Tout_r) / 2)
rho_subcool = AS.rhomass() #[kg/m^3]
self.Charge_subcool = self.w_subcool * self.V_r * rho_subcool
#Pressure drop calculations for subcooled refrigerant
v_r = 1 / rho_subcool
#Pressure gradient using Darcy friction factor
dpdz_r = -self.f_r_subcool * v_r * self.G_r**2 / (2 * self.ID
) #Pressure gradient
self.DP_r_subcool = dpdz_r * self.Lcircuit * self.w_subcool
# Positive Q is heat input to the refrigerant, negative Q is heat output from refrigerant.
# Heat is removed here from the refrigerant since it is condensing
self.Q_subcool = DWS.Q
self.fdry_subcool = DWS.f_dry
self.Tout_a_subcool = DWS.Tout_a
self.Tout_r = DWS.Tout_r
def _Supercrit_liq_Forward(self, w_supercrit_liq):
# **********************************************************************
# SUPERCRITICAL_LIQUID PART
# **********************************************************************
self.w_supercrit_liq = w_supercrit_liq
if self.w_supercrit_liq < 0:
raise ValueError(
'w_supercrit_liq in Gas cooler cannot be less than zero')
#AbstractState
AS = self.AS
DWS = DWSVals() #DryWetSegment structure
# Store temporary values to be passed to DryWetSegment
DWS.A_a = self.Fins.A_a * w_supercrit_liq
DWS.cp_da = self.Fins.cp_da
DWS.eta_a = self.Fins.eta_a
DWS.h_a = self.Fins.h_a * self.h_a_tuning #Heat transfer coefficient
DWS.mdot_da = self.mdot_da * w_supercrit_liq
DWS.pin_a = self.Fins.Air.p
DWS.Fins = self.Fins
DWS.FinsType = self.FinsType
# Inputs on the air side to two phase region are inlet air again
DWS.Tin_a = self.Tin_a
DWS.RHin_a = self.Fins.Air.RH
DWS.Tin_r = self.Tcr
DWS.A_r = self.A_r_wetted * w_supercrit_liq
DWS.Rw = self.Rw / w_supercrit_liq
AS.update(CP.PT_INPUTS, self.psat_r, self.Tcr - 1)
DWS.cp_r = AS.cpmass() #[J/kg-K]
DWS.pin_r = self.psat_r
DWS.mdot_r = self.mdot_r
DWS.IsTwoPhase = False
# # Friction factor and HTC in the refrigerant portions.
# # Average fluid temps are used for the calculation of properties
# # Average temp of refrigerant is average of sat. temp and outlet temp
# # Secondary fluid is air over the fins
# self.f_r_supercrit_liq, self.h_r_supercrit_liq, self.Re_r_supercrit_liq=f_h_1phase_Tube(
# self.mdot_r / self.Ncircuits, self.ID, self.Tcr-1.0, self.psat_r, self.AS,
# "Single")
#
# # Average Refrigerant heat transfer coefficient
# DWS.h_r=self.h_r_supercrit_liq*self.h_r_tuning
#
# #Run DryWetSegment
# DryWetSegment(DWS)
#
# AS.update(CP.PT_INPUTS, self.psat_r, (self.Tcr + DWS.Tout_r) / 2)
# rho_supercrit_liq=AS.rhomass() #[kg/m^3]
# self.Charge_supercrit_liq = self.w_supercrit_liq * self.V_r * rho_supercrit_liq
#
# #Pressure drop calculations for supercrit_liqed refrigerant
# v_r=1/rho_supercrit_liq
# #Pressure gradient using Darcy friction factor
# dpdz_r=-self.f_r_supercrit_liq*v_r*self.G_r**2/(2*self.ID) #Pressure gradient
# self.DP_r_supercrit_liq=dpdz_r*self.Lcircuit*self.w_supercrit_liq
#
# # Positive Q is heat input to the refrigerant, negative Q is heat output from refrigerant.
# # Heat is removed here from the refrigerant since it is condensing
# self.Q_supercrit_liq=DWS.Q
# self.fdry_supercrit_liq=DWS.f_dry
# self.Tout_a_supercrit_liq=DWS.Tout_a
# self.Tout_r=DWS.Tout_r
AS.update(CP.PT_INPUTS, self.psat_r, self.Tout_r_sc)
hout = AS.hmass() #[J/kg]
#Target heat transfer to go from inlet temperature (critical) to iterative outlet temperature
Q_target = self.mdot_r * (hout - self.hcr)
if Q_target > 0:
raise ValueError('Q_target in Gas cooler must be negative')
# Friction factor and HTC in the refrigerant portions.
# Average fluid temps are used for the calculation of properties
# Average temp of refrigerant is average of sat. temp and outlet temp
# Secondary fluid is air over the fins
h_r, self.f_r_supercrit_liq, DWS.cp_r, rho_supercrit_liq = Petterson_supercritical_average(
self.Tout_r_sc, self.Tcr, self.T_w, self.AS, self.G_r, self.ID, 0,
self.ID / self.Lcircuit, self.mdot_r / self.Ncircuits, self.psat_r,
-Q_target / DWS.A_r)
DWS.h_r = h_r * self.h_r_tuning #Correct refrigerant HTC with tuning factor
#Run DryWetSegment
DryWetSegment(DWS)
# Positive Q is heat input to the refrigerant, negative Q is heat output from refrigerant.
# Heat is removed here from the refrigerant since it is condensing
self.T_w = DWS.Twall_s #inner surface wall temperature (refrigerant)
self.Q_supercrit_liq = DWS.Q
self.h_r_supercrit_liq = DWS.h_r
self.fdry_supercrit_liq = DWS.f_dry
self.Tout_a_supercrit_liq = DWS.Tout_a
self.Tout_r = DWS.Tout_r
self.Charge_supercrit_liq = self.w_supercrit_liq * self.V_r * rho_supercrit_liq
#Pressure drop calculations for supercrit_liqed refrigerant
v_r = 1 / rho_supercrit_liq
#Pressure gradient using Darcy friction factor
dpdz_r = -self.f_r_supercrit_liq * v_r * self.G_r**2 / (
2 * self.ID) #Pressure gradient
self.DP_r_supercrit_liq = dpdz_r * self.Lcircuit * self.w_supercrit_liq
return Q_target - DWS.Q
def _TwoPhase_Forward(self, w_2phase):
DWS = DWSVals() #DryWetSegment structure
# Store temporary values to be passed to DryWetSegment
DWS.Fins = self.Fins
DWS.FinsType = self.FinsType
DWS.A_a = self.Fins.A_a * w_2phase
DWS.cp_da = self.Fins.cp_da
DWS.eta_a = self.Fins.eta_a
DWS.h_a = self.Fins.h_a * self.h_a_tuning #Heat transfer coefficient, not enthalpy
DWS.mdot_da = self.mdot_da * w_2phase
DWS.pin_a = self.Fins.Air.p
DWS.Tdew_r = self.Tdew_r
DWS.Tbubble_r = self.Tbubble_r
DWS.Tin_a = self.Tin_a
DWS.RHin_a = self.Fins.Air.RH
DWS.Tin_r = self.Tsat_r
DWS.A_r = self.A_r_wetted * w_2phase
DWS.Rw = self.Rw / w_2phase
DWS.cp_r = 1.0e15 #In the two-phase region the cp is infinite, use 1e15 as a big number;
DWS.pin_r = self.psat_r
DWS.mdot_r = self.mdot_r
DWS.IsTwoPhase = True
#Target heat transfer to go from inlet quality to saturated vapor
Q_target = self.mdot_r * (self.xout_2phase - self.xin_r) * self.h_fg
if Q_target < 0:
raise ValueError('Q_target in Evaporator must be positive')
# Average Refrigerant heat transfer coefficient
try:
if self.AS.name() in 'CarbonDioxide':
h_r = KandlikarEvaporation_average(self.xin_r,
self.xout_2phase, self.AS,
self.G_r, self.ID,
self.psat_r,
Q_target / DWS.A_r,
self.Tbubble_r, self.Tdew_r)
else:
h_r = ShahEvaporation_Average(self.xin_r, self.xout_2phase,
self.AS, self.G_r, self.ID,
self.psat_r, Q_target / DWS.A_r,
self.Tbubble_r, self.Tdew_r)
except:
h_r = ShahEvaporation_Average(self.xin_r, self.xout_2phase,
self.AS, self.G_r, self.ID,
self.psat_r, Q_target / DWS.A_r,
self.Tbubble_r, self.Tdew_r)
DWS.h_r = h_r * self.h_tp_tuning #correct refrigerant side convection heat transfer
#Run the DryWetSegment to carry out the heat and mass transfer analysis
DryWetSegment(DWS)
self.Q_2phase = DWS.Q
self.Q_sensible_2phase = DWS.Q_sensible
self.h_r_2phase = DWS.h_r
self.fdry_2phase = DWS.f_dry
self.Tout_a_2phase = DWS.Tout_a
rho_average = TwoPhaseDensity(self.AS,
self.xin_r,
self.xout_2phase,
self.Tdew_r,
self.Tbubble_r,
slipModel='Zivi')
self.Charge_2phase = rho_average * w_2phase * self.V_r
#Frictional pressure drop component
DP_frict = LMPressureGradientAvg(
self.xin_r, self.xout_2phase, self.AS, self.G_r, self.ID,
self.Tbubble_r, self.Tdew_r) * self.Lcircuit * w_2phase
#Accelerational pressure drop component
try:
if self.AS.name() in 'CarbonDioxide':
DP_accel = AccelPressureDrop(
self.xin_r,
self.xout_2phase,
self.AS,
self.G_r,
self.Tbubble_r,
self.Tdew_r,
D=self.ID,
slipModel='Premoli') * self.Lcircuit * w_2phase
else:
DP_accel = AccelPressureDrop(
self.xin_r,
self.xout_2phase,
self.AS,
self.G_r,
self.Tbubble_r,
self.Tdew_r,
slipModel='Zivi') * self.Lcircuit * w_2phase
except:
DP_accel = AccelPressureDrop(
self.xin_r,
self.xout_2phase,
self.AS,
self.G_r,
self.Tbubble_r,
self.Tdew_r,
slipModel='Zivi') * self.Lcircuit * w_2phase
self.DP_r_2phase = DP_frict + DP_accel
if self.Verbosity > 7:
print(w_2phase, DWS.Q, Q_target, self.xin_r,
"w_2phase,DWS.Q,Q_target,self.xin_r")
return DWS.Q - Q_target
def _TwoPhase_Forward(self,w_2phase):
DWS=DWSVals() #DryWetSegment structure
# Store temporary values to be passed to DryWetSegment
DWS.Fins=self.Fins
DWS.FinsType = self.FinsType
DWS.A_a=self.Fins.A_a*w_2phase
DWS.cp_da=self.Fins.cp_da
DWS.eta_a=self.Fins.eta_a
DWS.h_a=self.Fins.h_a*self.h_a_tuning #Heat transfer coefficient, not enthalpy
DWS.mdot_da=self.mdot_da*w_2phase
DWS.pin_a=self.Fins.Air.p
DWS.Tdew_r=self.Tdew_r
DWS.Tbubble_r=self.Tbubble_r
DWS.Tin_a=self.Tin_a
DWS.RHin_a=self.Fins.Air.RH
DWS.Tin_r=self.Tsat_r
DWS.A_r=self.A_r_wetted*w_2phase
DWS.Rw=self.Rw/w_2phase
DWS.cp_r=1.0e15 #In the two-phase region the cp is infinite, use 1e15 as a big number;
DWS.pin_r=self.psat_r
DWS.mdot_r=self.mdot_r
DWS.IsTwoPhase=True
#Target heat transfer to go from inlet quality to saturated vapor
Q_target=self.mdot_r*(self.xout_2phase-self.xin_r)*self.h_fg
if Q_target<0:
raise ValueError('Q_target in Evaporator must be positive')
# Average Refrigerant heat transfer coefficient
#Shah correlation
#h_r=ShahEvaporation_Average(self.xin_r,self.xout_2phase,self.AS,self.G_r,self.Dh,self.psat_r,Q_target/DWS.A_r,self.Tbubble_r,self.Tdew_r)
#Bertsch correlation
#h_r=Bertsch_MC_Average(self.xin_r,self.xout_2phase,self.AS,self.G_r,self.Dh,Q_target/DWS.A_r,self.Lcircuit,self.Tbubble_r,self.Tdew_r)
#Kandlikar correlation
#h_r=KandlikarEvaporation_average(self.xin_r,self.xout_2phase,self.AS,self.G_r,self.Dh,self.psat_r,Q_target/DWS.A_r,self.Tbubble_r,self.Tdew_r)
#Kim and Mudawar (2013)
DPDZ_frict_2phase, h_r = KM_Evap_Average(self.xin_r,self.xout_2phase,self.AS,self.G_r,self.Dh,self.Tbubble_r,self.Tdew_r,self.psat_r,self.beta,Q_target/DWS.A_r,self.PH_PF)
DWS.h_r=h_r*self.h_tp_tuning #correct refrigerant side convection heat transfer
#Run the DryWetSegment to carry out the heat and mass transfer analysis
DryWetSegment(DWS)
self.Q_2phase=DWS.Q
self.Q_sensible_2phase=DWS.Q_sensible
self.h_r_2phase=DWS.h_r
self.fdry_2phase=DWS.f_dry
self.Tout_a_2phase=DWS.Tout_a
rho_average=TwoPhaseDensity(self.AS,self.xin_r,self.xout_2phase,self.Tdew_r,self.Tbubble_r,slipModel='Zivi')
self.Charge_2phase = rho_average * w_2phase * self.V_r
#Frictional pressure drop component
#Lockhart-Martinelli correlation
#DP_frict=LMPressureGradientAvg(self.xin_r,self.xout_2phase,self.AS,self.G_r,self.Dh,self.Tbubble_r,self.Tdew_r)*self.Lcircuit*w_2phase
#using the pressure gradient of Kim & Mudawar (2013)
DP_frict=DPDZ_frict_2phase*self.Lcircuit*w_2phase
#Accelerational pressure drop component
if self.Ref in 'CarbonDioxide' or 'CO2' or 'R744': #TODO: self.AS.name() is not available yet for all backends, using self.Ref for now
DP_accel=AccelPressureDrop(self.xin_r,self.xout_2phase,self.AS,self.G_r,self.Tbubble_r,self.Tdew_r,D=self.Dh,slipModel='Premoli')*self.Lcircuit*w_2phase
else:
DP_accel=AccelPressureDrop(self.xin_r,self.xout_2phase,self.AS,self.G_r,self.Tbubble_r,self.Tdew_r,slipModel='Zivi')*self.Lcircuit*w_2phase
self.DP_r_2phase=DP_frict+DP_accel;
if self.Verbosity>7:
print (w_2phase,DWS.Q,Q_target,self.xin_r,"w_2phase,DWS.Q,Q_target,self.xin_r")
return DWS.Q-Q_target