Module huracan.thermo.fluids
Huracan fluid models
Expand source code
# SPDX-FileCopyrightText: © 2021 Antonio López Rivera <antonlopezr99@gmail.com>
# SPDX-License-Identifier: GPL-3.0-only
"""
Huracan fluid models
--------------------
"""
from copy import deepcopy
from huracan.constants import R
from huracan.engine import stream, component
from huracan.thermo.processes import absolute, diffusion, compression, heat_exchange, expansion
class fluid:
"""
Fluid
-----
"""
@classmethod
def _diversion(cls, f, fr):
"""
Fluid diversion.
- Diverted flow mass flow: fraction*mf
- Main flow mass flow: (1-fraction)*mf
:param f: Fluid to be diverted.
:param fr: Fraction of diverted fluid.
:type f: mixture or fluid
:type fr: 0 <= float <= 1
:return: [fluid] Main flow
[fluid] Diverted flow
"""
mf, df = deepcopy(f), deepcopy(f)
mf.mf *= 1 - fr
df.mf *= fr
return mf, df
def __mul__(self, other):
"""
Return two flows representing the diversion.
"""
return self._diversion(self, other)
def __rmul__(self, other):
"""
Return two flows representing the diversion.
"""
return self._diversion(self, other)
class gas(fluid):
"""
Ideal gas model
---------------
All gas phenomena are modelled using its
- Mass flow
- Constant pressure specific heat capacity
- Ratio of specific heat capacities
"""
def __init__(self, mf, cp, k,
m, t_0, p_0):
"""
:param mf: [kg] Mass flow
:param cp: [-] Constant pressure specific heat
:param k: [-] Specific heat ratio
:param m: [M] Flow Mach number |
:param t_0: [K] Initial temperature | -> Total pressure and temperature calculated from inputs
:param p_0: [Pa] Initial pressure |
:type mf: float
:type cp: (T: float) -> float
:type k: (T: float) -> float
:type m: float
:type t_0: float
:type p_0: float
"""
self.mf = mf
self.cp = cp
self.k = k
self.m = m
self.v_0 = m*(k(t_0)*R*t_0)**0.5
self.t_0 = t_0
self.p_0 = p_0
self.absolute()
# Set the gas' initial entropy as 0
self.S = 0
def state(self):
"""
Update gas state variables.
- V - Specific volume
- S - Specific entropy
- H - Specific enthalpy
"""
self.V = self.t0*R/self.p0
self.E = self.cp(self.t0)/self.k(self.t0)*self.t0
self.H = self.E + self.p0*self.V
def __add__(self, other):
"""
Mixture creation operator: <gas> + <gas>
In the case of adding fuel to a gas, the
following assumptions are considered:
- Total temperature and pressure of gas are
unaltered.
- Constant pressure specific heat capacity Cp
of gas is unaltered.
- Ratio of specific heats k of gas is unaltered.
:type other: gas or fuel
"""
if isinstance(other, gas):
return mixture(self, other)
if isinstance(other, fuel):
self.mf += other.mf
return self
def __sub__(self, other):
"""
Stream creation operator: <gas> + <component/stream>
:type other: component or stream
:return: stream instance
"""
if isinstance(other, component):
s = stream(self)-other
return s
elif isinstance(other, stream):
other.gas = self
return other
def absolute(self):
"""
Returns the absolute temperature and pressure of a gas
flowing at a certain Mach number.
:return: process data class instance
"""
k = self.k(self.t_0)
p = absolute(k = k,
m = self.m,
t_0 = self.t_0,
p_0 = self.p_0)
self.t0 = p.t0
self.p0 = p.p0
self.state()
return p
def diffusion(self, eta,
PI=None,
TAU=None):
"""
Diffusion
---------
Assumptions:
- Adiabatic
- Reversible
- Temperature remains constant through process
The absolute pressure change is determined by the total pressure ratio
_PI_ if provided. Else, _PI_ is calculated using the isentropic
efficiency _nu_.
:param eta: [-] Isentropic efficiency
:param PI: [-] Pressure ratio
:type eta: float
:type PI: float
:return: process instance
"""
k = self.k(self.t0)
cp = self.cp(self.t0)
p = diffusion(mf = self.mf,
cp = cp,
k = k,
m = self.m,
t_0 = self.t_0,
p_0 = self.p_0,
eta = eta,
PI = PI,
TAU = TAU,
t0 = self.t0 if hasattr(self, 't0') else None,
p0 = self.p0 if hasattr(self, 'p0') else None
)
self.t0 = p.t01
self.p0 = p.p01
self.state()
return p
def compression(self, eta,
PI=None,
TAU=None,
):
"""
Compression
-----------
Assumptions:
- Adiabatic
- Reversible
Input pairs:
- eta, PI
- TAU is calculated
- eta, TAU
- PI is calculated
:param eta: [-] Isentropic efficiency
:param PI: [-] Pressure ratio
:param TAU: [-] Temperature ratio
:type eta: float
:type PI: float
:type TAU: float
:return: process instance
"""
k = self.k(self.t0)
cp = self.cp(self.t0)
p = compression(mf = self.mf,
cp = cp,
k = k,
t00 = self.t0,
p00 = self.p0,
eta = eta,
PI = PI,
TAU = TAU,
)
self.t0 = p.t01
self.p0 = p.p01
self.state()
return p
def expansion(self, eta,
PI=None,
TAU=None,
):
"""
Expansion
---------
Assumptions:
- Adiabatic
- Reversible
Input pairs:
- PI, eta
- TAU is calculated
- TAU, eta
- PI is calculated
:param eta: [-] Isentropic efficiency
:param PI: [-] Pressure ratio
:param TAU: [-] Temperature ratio
:type eta: float
:type PI: float
:type TAU: float
:return: process instance
"""
k = self.k(self.t0)
cp = self.cp(self.t0)
p = expansion(mf = self.mf,
cp = cp,
k = k,
t00 = self.t0,
p00 = self.p0,
eta = eta,
PI = PI,
TAU = TAU,
)
self.t0 = p.t01
self.p0 = p.p01
self.state()
return p
def heat_exchange(self,
eta,
cp,
Q_ex,
PI=1):
"""
Isobaric heat exchange
----------------------
Assumptions:
- Perfect heat addition
The pressure ratio is assumed to be constant,
however a pressure ratio different than 1 can
be input to the function in case the process
cannot be assumed to be isobaric.
:param eta: Isentropic efficiency
:param cp: Specific heat of gas during heat addition
:param Q_ex: Heat received by the gas in the heat exchange
:type eta: float
:type cp: float
:type Q_ex: float
:type PI: float
"""
p = heat_exchange(mf = self.mf,
cp = cp,
t00 = self.t0,
p00 = self.p0,
Q_ex = Q_ex,
eta = eta,
PI = PI)
self.t0 = p.t01
self.p0 = p.p01
self.S += Q_ex/self.t0
self.state()
return p
class fuel:
"""
Fuel model
----------
"""
def __init__(self, LHV,
mf=None):
"""
:param LHV: Fuel Lower Heating Value (heat of combustion)
:param mf: Fuel mass flow
"""
self.LHV = LHV
self.mf = mf
class mixture(gas):
"""
Mixture model
-------------
"""
@classmethod
def _mix_t0(cls, gas1, gas2):
"""
Total temperature of fluid mixture.
"""
n = gas1.mf*gas1.cp(gas1.t0)*gas1.t0 + gas2.mf*gas2.cp(gas2.t0)*gas2.t0
d = gas1.mf*gas1.cp(gas1.t0) + gas2.mf*gas2.cp(gas2.t0)
t0_f = n / d
return t0_f
@classmethod
def _mix_p0(cls, gas1, gas2):
"""
Total pressure of fluid mixture.
"""
n = gas1.p0*gas1.mf + gas2.p0*gas2.mf
d = gas1.mf + gas2.mf
p0_f = n / d
return p0_f
@classmethod
def _mix_cp(cls, gas1, gas2):
"""
Constant pressure specific heat at of fluid mixture.
"""
cp_f = lambda t: (gas1.cp(t)*gas1.mf + gas2.cp(t)*gas2.mf) / (gas1.mf + gas2.mf)
return cp_f
@classmethod
def _mix_k(cls, gas1, gas2):
"""
Specific heat ratio of fluid mixture.
"""
cp_f = lambda t: (gas1.k(t)*gas1.mf + gas2.k(t)*gas2.mf) / (gas1.mf + gas2.mf)
return cp_f
def __init__(self, gas1, gas2):
"""
:param gas1: Mixture fluid 1
:param gas2: Mixture fluid 2
:type gas1: gas or mixture
:type gas2: gas or mixture
"""
mf = gas1.mf + gas2.mf
super().__init__(mf = mf,
cp = self._mix_cp(gas1, gas2),
k = self._mix_k(gas1, gas2),
m = 0,
t_0 = self._mix_t0(gas1, gas2),
p_0 = self._mix_p0(gas1, gas2))Classes
class fluid-
Fluid
Expand source code
class fluid: """ Fluid ----- """ @classmethod def _diversion(cls, f, fr): """ Fluid diversion. - Diverted flow mass flow: fraction*mf - Main flow mass flow: (1-fraction)*mf :param f: Fluid to be diverted. :param fr: Fraction of diverted fluid. :type f: mixture or fluid :type fr: 0 <= float <= 1 :return: [fluid] Main flow [fluid] Diverted flow """ mf, df = deepcopy(f), deepcopy(f) mf.mf *= 1 - fr df.mf *= fr return mf, df def __mul__(self, other): """ Return two flows representing the diversion. """ return self._diversion(self, other) def __rmul__(self, other): """ Return two flows representing the diversion. """ return self._diversion(self, other)Subclasses
class fuel (LHV, mf=None)-
Fuel Model
:param LHV: Fuel Lower Heating Value (heat of combustion) :param mf: Fuel mass flow
Expand source code
class fuel: """ Fuel model ---------- """ def __init__(self, LHV, mf=None): """ :param LHV: Fuel Lower Heating Value (heat of combustion) :param mf: Fuel mass flow """ self.LHV = LHV self.mf = mf class gas (mf, cp, k, m, t_0, p_0)-
Ideal Gas Model
All gas phenomena are modelled using its - Mass flow - Constant pressure specific heat capacity - Ratio of specific heat capacities
:param mf: [kg] Mass flow :param cp: [-] Constant pressure specific heat :param k: [-] Specific heat ratio :param m: [M] Flow Mach number | :param t_0: [K] Initial temperature | -> Total pressure and temperature calculated from inputs :param p_0: [Pa] Initial pressure |
:type mf: float :type cp: (T: float) -> float :type k: (T: float) -> float :type m: float :type t_0: float :type p_0: float
Expand source code
class gas(fluid): """ Ideal gas model --------------- All gas phenomena are modelled using its - Mass flow - Constant pressure specific heat capacity - Ratio of specific heat capacities """ def __init__(self, mf, cp, k, m, t_0, p_0): """ :param mf: [kg] Mass flow :param cp: [-] Constant pressure specific heat :param k: [-] Specific heat ratio :param m: [M] Flow Mach number | :param t_0: [K] Initial temperature | -> Total pressure and temperature calculated from inputs :param p_0: [Pa] Initial pressure | :type mf: float :type cp: (T: float) -> float :type k: (T: float) -> float :type m: float :type t_0: float :type p_0: float """ self.mf = mf self.cp = cp self.k = k self.m = m self.v_0 = m*(k(t_0)*R*t_0)**0.5 self.t_0 = t_0 self.p_0 = p_0 self.absolute() # Set the gas' initial entropy as 0 self.S = 0 def state(self): """ Update gas state variables. - V - Specific volume - S - Specific entropy - H - Specific enthalpy """ self.V = self.t0*R/self.p0 self.E = self.cp(self.t0)/self.k(self.t0)*self.t0 self.H = self.E + self.p0*self.V def __add__(self, other): """ Mixture creation operator: <gas> + <gas> In the case of adding fuel to a gas, the following assumptions are considered: - Total temperature and pressure of gas are unaltered. - Constant pressure specific heat capacity Cp of gas is unaltered. - Ratio of specific heats k of gas is unaltered. :type other: gas or fuel """ if isinstance(other, gas): return mixture(self, other) if isinstance(other, fuel): self.mf += other.mf return self def __sub__(self, other): """ Stream creation operator: <gas> + <component/stream> :type other: component or stream :return: stream instance """ if isinstance(other, component): s = stream(self)-other return s elif isinstance(other, stream): other.gas = self return other def absolute(self): """ Returns the absolute temperature and pressure of a gas flowing at a certain Mach number. :return: process data class instance """ k = self.k(self.t_0) p = absolute(k = k, m = self.m, t_0 = self.t_0, p_0 = self.p_0) self.t0 = p.t0 self.p0 = p.p0 self.state() return p def diffusion(self, eta, PI=None, TAU=None): """ Diffusion --------- Assumptions: - Adiabatic - Reversible - Temperature remains constant through process The absolute pressure change is determined by the total pressure ratio _PI_ if provided. Else, _PI_ is calculated using the isentropic efficiency _nu_. :param eta: [-] Isentropic efficiency :param PI: [-] Pressure ratio :type eta: float :type PI: float :return: process instance """ k = self.k(self.t0) cp = self.cp(self.t0) p = diffusion(mf = self.mf, cp = cp, k = k, m = self.m, t_0 = self.t_0, p_0 = self.p_0, eta = eta, PI = PI, TAU = TAU, t0 = self.t0 if hasattr(self, 't0') else None, p0 = self.p0 if hasattr(self, 'p0') else None ) self.t0 = p.t01 self.p0 = p.p01 self.state() return p def compression(self, eta, PI=None, TAU=None, ): """ Compression ----------- Assumptions: - Adiabatic - Reversible Input pairs: - eta, PI - TAU is calculated - eta, TAU - PI is calculated :param eta: [-] Isentropic efficiency :param PI: [-] Pressure ratio :param TAU: [-] Temperature ratio :type eta: float :type PI: float :type TAU: float :return: process instance """ k = self.k(self.t0) cp = self.cp(self.t0) p = compression(mf = self.mf, cp = cp, k = k, t00 = self.t0, p00 = self.p0, eta = eta, PI = PI, TAU = TAU, ) self.t0 = p.t01 self.p0 = p.p01 self.state() return p def expansion(self, eta, PI=None, TAU=None, ): """ Expansion --------- Assumptions: - Adiabatic - Reversible Input pairs: - PI, eta - TAU is calculated - TAU, eta - PI is calculated :param eta: [-] Isentropic efficiency :param PI: [-] Pressure ratio :param TAU: [-] Temperature ratio :type eta: float :type PI: float :type TAU: float :return: process instance """ k = self.k(self.t0) cp = self.cp(self.t0) p = expansion(mf = self.mf, cp = cp, k = k, t00 = self.t0, p00 = self.p0, eta = eta, PI = PI, TAU = TAU, ) self.t0 = p.t01 self.p0 = p.p01 self.state() return p def heat_exchange(self, eta, cp, Q_ex, PI=1): """ Isobaric heat exchange ---------------------- Assumptions: - Perfect heat addition The pressure ratio is assumed to be constant, however a pressure ratio different than 1 can be input to the function in case the process cannot be assumed to be isobaric. :param eta: Isentropic efficiency :param cp: Specific heat of gas during heat addition :param Q_ex: Heat received by the gas in the heat exchange :type eta: float :type cp: float :type Q_ex: float :type PI: float """ p = heat_exchange(mf = self.mf, cp = cp, t00 = self.t0, p00 = self.p0, Q_ex = Q_ex, eta = eta, PI = PI) self.t0 = p.t01 self.p0 = p.p01 self.S += Q_ex/self.t0 self.state() return pAncestors
Subclasses
Methods
def absolute(self)-
Returns the absolute temperature and pressure of a gas flowing at a certain Mach number.
:return: process data class instance
Expand source code
def absolute(self): """ Returns the absolute temperature and pressure of a gas flowing at a certain Mach number. :return: process data class instance """ k = self.k(self.t_0) p = absolute(k = k, m = self.m, t_0 = self.t_0, p_0 = self.p_0) self.t0 = p.t0 self.p0 = p.p0 self.state() return p def compression(self, eta, PI=None, TAU=None)-
Compression
Assumptions: - Adiabatic - Reversible
Input pairs: - eta, PI - TAU is calculated - eta, TAU - PI is calculated
:param eta: [-] Isentropic efficiency :param PI: [-] Pressure ratio :param TAU: [-] Temperature ratio
:type eta: float :type PI: float :type TAU: float
:return: process instance
Expand source code
def compression(self, eta, PI=None, TAU=None, ): """ Compression ----------- Assumptions: - Adiabatic - Reversible Input pairs: - eta, PI - TAU is calculated - eta, TAU - PI is calculated :param eta: [-] Isentropic efficiency :param PI: [-] Pressure ratio :param TAU: [-] Temperature ratio :type eta: float :type PI: float :type TAU: float :return: process instance """ k = self.k(self.t0) cp = self.cp(self.t0) p = compression(mf = self.mf, cp = cp, k = k, t00 = self.t0, p00 = self.p0, eta = eta, PI = PI, TAU = TAU, ) self.t0 = p.t01 self.p0 = p.p01 self.state() return p def diffusion(self, eta, PI=None, TAU=None)-
Diffusion
Assumptions: - Adiabatic - Reversible - Temperature remains constant through process
The absolute pressure change is determined by the total pressure ratio PI if provided. Else, PI is calculated using the isentropic efficiency nu.
:param eta: [-] Isentropic efficiency :param PI: [-] Pressure ratio
:type eta: float :type PI: float
:return: process instance
Expand source code
def diffusion(self, eta, PI=None, TAU=None): """ Diffusion --------- Assumptions: - Adiabatic - Reversible - Temperature remains constant through process The absolute pressure change is determined by the total pressure ratio _PI_ if provided. Else, _PI_ is calculated using the isentropic efficiency _nu_. :param eta: [-] Isentropic efficiency :param PI: [-] Pressure ratio :type eta: float :type PI: float :return: process instance """ k = self.k(self.t0) cp = self.cp(self.t0) p = diffusion(mf = self.mf, cp = cp, k = k, m = self.m, t_0 = self.t_0, p_0 = self.p_0, eta = eta, PI = PI, TAU = TAU, t0 = self.t0 if hasattr(self, 't0') else None, p0 = self.p0 if hasattr(self, 'p0') else None ) self.t0 = p.t01 self.p0 = p.p01 self.state() return p def expansion(self, eta, PI=None, TAU=None)-
Expansion
Assumptions: - Adiabatic - Reversible
Input pairs: - PI, eta - TAU is calculated - TAU, eta - PI is calculated
:param eta: [-] Isentropic efficiency :param PI: [-] Pressure ratio :param TAU: [-] Temperature ratio
:type eta: float :type PI: float :type TAU: float
:return: process instance
Expand source code
def expansion(self, eta, PI=None, TAU=None, ): """ Expansion --------- Assumptions: - Adiabatic - Reversible Input pairs: - PI, eta - TAU is calculated - TAU, eta - PI is calculated :param eta: [-] Isentropic efficiency :param PI: [-] Pressure ratio :param TAU: [-] Temperature ratio :type eta: float :type PI: float :type TAU: float :return: process instance """ k = self.k(self.t0) cp = self.cp(self.t0) p = expansion(mf = self.mf, cp = cp, k = k, t00 = self.t0, p00 = self.p0, eta = eta, PI = PI, TAU = TAU, ) self.t0 = p.t01 self.p0 = p.p01 self.state() return p def heat_exchange(self, eta, cp, Q_ex, PI=1)-
Isobaric Heat Exchange
Assumptions: - Perfect heat addition
The pressure ratio is assumed to be constant, however a pressure ratio different than 1 can be input to the function in case the process cannot be assumed to be isobaric.
:param eta: Isentropic efficiency :param cp: Specific heat of gas during heat addition :param Q_ex: Heat received by the gas in the heat exchange
:type eta: float :type cp: float :type Q_ex: float :type PI: float
Expand source code
def heat_exchange(self, eta, cp, Q_ex, PI=1): """ Isobaric heat exchange ---------------------- Assumptions: - Perfect heat addition The pressure ratio is assumed to be constant, however a pressure ratio different than 1 can be input to the function in case the process cannot be assumed to be isobaric. :param eta: Isentropic efficiency :param cp: Specific heat of gas during heat addition :param Q_ex: Heat received by the gas in the heat exchange :type eta: float :type cp: float :type Q_ex: float :type PI: float """ p = heat_exchange(mf = self.mf, cp = cp, t00 = self.t0, p00 = self.p0, Q_ex = Q_ex, eta = eta, PI = PI) self.t0 = p.t01 self.p0 = p.p01 self.S += Q_ex/self.t0 self.state() return p def state(self)-
Update gas state variables. - V - Specific volume - S - Specific entropy - H - Specific enthalpy
Expand source code
def state(self): """ Update gas state variables. - V - Specific volume - S - Specific entropy - H - Specific enthalpy """ self.V = self.t0*R/self.p0 self.E = self.cp(self.t0)/self.k(self.t0)*self.t0 self.H = self.E + self.p0*self.V
class mixture (gas1, gas2)-
Mixture Model
:param gas1: Mixture fluid 1 :param gas2: Mixture fluid 2
:type gas1: gas or mixture :type gas2: gas or mixture
Expand source code
class mixture(gas): """ Mixture model ------------- """ @classmethod def _mix_t0(cls, gas1, gas2): """ Total temperature of fluid mixture. """ n = gas1.mf*gas1.cp(gas1.t0)*gas1.t0 + gas2.mf*gas2.cp(gas2.t0)*gas2.t0 d = gas1.mf*gas1.cp(gas1.t0) + gas2.mf*gas2.cp(gas2.t0) t0_f = n / d return t0_f @classmethod def _mix_p0(cls, gas1, gas2): """ Total pressure of fluid mixture. """ n = gas1.p0*gas1.mf + gas2.p0*gas2.mf d = gas1.mf + gas2.mf p0_f = n / d return p0_f @classmethod def _mix_cp(cls, gas1, gas2): """ Constant pressure specific heat at of fluid mixture. """ cp_f = lambda t: (gas1.cp(t)*gas1.mf + gas2.cp(t)*gas2.mf) / (gas1.mf + gas2.mf) return cp_f @classmethod def _mix_k(cls, gas1, gas2): """ Specific heat ratio of fluid mixture. """ cp_f = lambda t: (gas1.k(t)*gas1.mf + gas2.k(t)*gas2.mf) / (gas1.mf + gas2.mf) return cp_f def __init__(self, gas1, gas2): """ :param gas1: Mixture fluid 1 :param gas2: Mixture fluid 2 :type gas1: gas or mixture :type gas2: gas or mixture """ mf = gas1.mf + gas2.mf super().__init__(mf = mf, cp = self._mix_cp(gas1, gas2), k = self._mix_k(gas1, gas2), m = 0, t_0 = self._mix_t0(gas1, gas2), p_0 = self._mix_p0(gas1, gas2))Ancestors
Inherited members