Exemplo n.º 1
0
def input_properties_case_REFPROP___ButaneOctane(comp1, comp2, kij):
    this_function_name = sys._getframe().f_code.co_name
    print('\n---\n THE DATA USED IN THIS SIMULATION WAS OBTAINED FROM: ', this_function_name)
    print('\n---\n')
    '''
                                                
    SOURCE: REFPROP -- BUTANE AND OCTANE.
    
    '''

    critical_pressure = np.array([comp1.pC, comp2.pC])
    critical_temperature = np.array([comp1.TC, comp2.TC])
    acentric_factor = np.array([comp1.AcF, comp2.AcF])
    molar_mass = np.array([comp1.MM, comp2.MM])
    omega_a = 0.45724 * np.ones_like(molar_mass)
    omega_b = 0.07780 * np.ones_like(molar_mass)


    binary_interaction = np.array(
        [[0.0000, kij],
         [kij, 0.0000]]
    )
    specific_heat_mass_base = np.array([comp1.Cp, comp2.Cp])

    specific_heat = Tools_Convert.convert_specific_heat_massbase_TO_molarbase(specific_heat_mass_base, molar_mass)

    return (critical_pressure, critical_temperature, acentric_factor, molar_mass, omega_a, omega_b,
            binary_interaction, specific_heat)
Exemplo n.º 2
0
def solution_concentration_set_function(lightComponent, molar_weight, base):
    '''
    This function is useful to obtain mass fraction and molar fraction VECTOR of a BINARY mixture \n


    lightComponent: the subcooled liquid solution concentration is set up ...
                ... based on R134a concentration (e.g.: 5./100, 0.05/100, etc...) \n
    MM: vector with molar weight of each component "i" [kg/kmol], i.e., (MM = ([MMrefrig, MMpoe])) \n
    base: 'molar' or 'mass' [-]; you need inform one of them \n
    z: vector concentration [-], i.e., (z = ([zR, zO])) \n
    z_mass: vector mass concentration [-] (z_mass = ([zR_mass, zO_mass])) \n

    Return: z, z_mass
    '''
    MM = molar_weight

    nome_desta_funcao = sys._getframe().f_code.co_name
    if lightComponent > 1. or lightComponent < 0.0:
        raise Exception('You entered with a concentration out of expected range whe you calls the function ' + str(nome_desta_funcao))
    elif MM.shape[0] != 2:
        raise Exception('You must entered a vector like MM = ([MM1,MM2]) when you calls the function '
                        + str(nome_desta_funcao))
    elif base != 'mass' and 'molar':
        raise Exception('You need type \'mass\' or \'molar\' when calls the function: ' + str(nome_desta_funcao))

    zin = np.array([lightComponent, (1. - lightComponent)])
    z, z_mass = Tools_Convert.frac_input(MM, zin, base)
    return z, z_mass
Exemplo n.º 3
0
    def specificVolumeLiquid_Wrap(self, pressure, temperature, molar_weight, molar_composition, density_model):
        '''
        This function chooses density from EXperimental CORrelation ('jpDias') or from THErmodynamics ('ELV') \n

        T: temperature [K] \n
        p: pressure [Pa] \n
        MM: vector with molar weight of each component "i" [kg/kmol], i.e., (MM = ([MMrefrig, MMpoe])) \n
        x: vector molar concentration [-], i.e., (x = ([xR, xO])) \n
        x_mass: vector mass concentration [-] (x_mass = ([xR_mass, xO_mass])) \n
        spvolL: specific volume from correlation 'jpDias' or from 'ELV' [m3/kg] \n

        Return: spvolL'''
        p, T, MM, x = pressure, temperature, molar_weight, molar_composition

        nome_desta_funcao = sys._getframe().f_code.co_name
        x_mass = Tools_Convert.convert_molarfrac_TO_massfrac(MM, x)
        density_models = ['ELV', 'jpDias']
        if density_model not in density_models:
            msg = 'Invalid density model in --> %s' % nome_desta_funcao
            msg += '\t Choose one of the models: %s' % density_models
            raise Exception(msg)
        if density_model == 'ELV':
            densL = super().calculate_density_phase(p, T, MM, x, fluid_type='liquid')
        elif density_model == 'jpDias':
            densL = self.densityLiquid_jpDias_SEC(T, p, x_mass)
        spvolL = np.power(densL, -1) 
        return spvolL
def main():
    #[1] - INPUT DATA
    p = 15e5
    T = 300.
    LC, base = 99. / 100, 'mass'  # <=============================== change here if necessary
    #[2] - CHANGING BASE
    zin = np.array([LC, (1. - LC)])
    z, _z_mass = Tools_Convert.frac_input(MM, zin, base)
    #[3] - STANDARD VALUES
    hR = hR_mass * prop_obj.calculate_weight_molar_mixture(
        MM, z, 'saturated_liquid')
    sR = sR_mass * prop_obj.calculate_weight_molar_mixture(
        MM, z, 'saturated_liquid')
    #[4] - CREATING THE OBJECT
    hsfv_obj = HSFv(pC, TR, Tc, AcF, Cp, MM, hR, sR)
    #[5] - GETTING THE RESULTS
    F_V, h, s = hsfv_obj(p, T, z)
Exemplo n.º 5
0
LEGEND:
name: compost name
MM: molar mass of each component [kg/kmol]
Tc: critical temperature [K] 
pC: critical pressure [Pa]
AcF: acentric factor [-]
Cp: specific heat [J / kg K]   !<=== HERE IT IS IN MASS BASE, BUT IT IS CONVERTED TO MOLAR BASE INSIDE THE FUNCTION 
=============================================================================================================
'''
'''OBS-1: For while, I don't have specific heat lubrificant oil POE-ISO-VG-10'''

MM = np.array([102.03, 425.])  #425.
specific_heat_mass_base = np.array(
    [0.82421, 2.45681]
) * 1.e3  # [J / kg K] @ 20ºC (Coolpropgit available on: http://ibell.pythonanywhere.com; see OBS-1) 2.45681
specific_heat = Tools_Convert.convert_specific_heat_massbase_TO_molarbase(
    specific_heat_mass_base, MM)

#sort as name, molar_mass, Tc, pC, AcF, Cp
comp1 = Molecule("R134a", MM[0], 374.21, 40.5928e5, 0.32684,
                 specific_heat[0])  # [SOURCE II]
comp2 = Molecule(
    "POE-ISO-10", MM[1], (595.8 + 273.15), 6.92e5, 1.0659, specific_heat[1]
)  # [SOURCE I] ¿specific_heat POE ISO VG 10 não tem no artigo?
kij = -0.002851  # [SOURCE I]
'''
===============================================================================================================
Do you have kij above? If you don't have it ==> uncomment the CODE's 4 lines below 
===============================================================================================================
'''
# p_C = np.array([comp1.pC, comp2.pC])
# T_C = np.array([comp1.TC, comp2.TC])
 def __call__(self, p, T, z):
     pC, TR, Tc = self.pC, self.TR, self.Tc
     AcF, Cp, MM, hR, sR = self.AcF, self.Cp, self.MM, self.hR, self.sR
     pB, _y_sat, _Sy, _counter = bubble_obj(T, z)
     pR = pB  #<----setting the reference pressure equal bubble pressure
     if __name__ == '__main__':
         print(self)
         print(
             'You\'re running pressure = %.3e [Pa] and temperature = %.2f C'
             % (p, (T - 273.15)))
         print(
             'For this temperature T = (%.2f C) the bubble pressure is: pB = %.3e [Pa]'
             % ((T - 273.15), pB))
         print(
             '\n---------------------------------------------------------)')
     if (p >= pB):
         F_V = 0.0
         H_subcooled_molar = prop_obj.calculate_enthalpy(
             TR, T, pR, p, z, z, hR, Cp, 'liquid')
         M_L = prop_obj.calculate_weight_molar_mixture(MM, z, 'liquid')
         h_subcooled_mass = H_subcooled_molar * np.reciprocal(M_L)
         S_subcooled_molar = prop_obj.calculate_entropy(
             TR, T, pR, p, z, z, sR, Cp, 'liquid')
         s_subcooled_mass = S_subcooled_molar * np.reciprocal(M_L)
         H, h, S, s = H_subcooled_molar, h_subcooled_mass, S_subcooled_molar, s_subcooled_mass
         if __name__ == '__main__':
             print('--> This @(p,T) falls into single phase region')
             print('\nSubcooled liquid enthalpy h = %.3e [J/ kmol]' % H)
             print('\nSubcooled liquid entropy s = %.3e [J/(kmol K)]' % S)
             print('\nSubcooled liquid entalpy h = %.3e [J/ kg]' % h)
             print('\nSubcooled liquid entropy s = %.3e [J/(kg K)]' % s)
     else:
         F_V, _is_stable, K_values_newton, _initial_K_values = \
         FlashAlgorithm_main.getting_the_results_from_FlashAlgorithm_main(p, T, pC, Tc, AcF, z)
         x = z / (F_V * (K_values_newton - 1.) + 1.)
         y = K_values_newton * x
         x_mass = Tools_Convert.convert_molarfrac_TO_massfrac(MM, x)
         y_mass = Tools_Convert.convert_molarfrac_TO_massfrac(MM, y)
         #Enthalpy
         H_sat_vapor_molar = prop_obj.calculate_enthalpy(
             TR, T, pR, p, y, z, hR, Cp, 'saturated_vapor')
         M_V = prop_obj.calculate_weight_molar_mixture(
             MM, y, 'saturated_vapor')
         h_sat_vapor_mass = H_sat_vapor_molar * np.reciprocal(M_V)
         H_sat_liquid_molar = prop_obj.calculate_enthalpy(
             TR, T, pR, p, x, z, hR, Cp, 'saturated_liquid')
         M_L = prop_obj.calculate_weight_molar_mixture(
             MM, x, 'saturated_liquid')
         h_sat_liquid_mass = H_sat_liquid_molar * np.reciprocal(M_L)
         H_enthalpy_mixture_molar = (
             1. - F_V) * H_sat_liquid_molar + F_V * H_sat_vapor_molar
         F_V_mass = np.reciprocal((M_L / M_V) * (1 / F_V - 1.) + 1.)
         h_enthalpy_mixture_mass = (
             1. -
             F_V_mass) * h_sat_liquid_mass + F_V_mass * h_sat_vapor_mass
         #Entropy
         S_sat_vapor_molar = prop_obj.calculate_entropy(
             TR, T, pR, p, y, z, sR, Cp, 'vapor')
         s_sat_vapor_mass = S_sat_vapor_molar * np.reciprocal(M_V)
         S_sat_liquid_molar = prop_obj.calculate_entropy(
             TR, T, pR, p, x, z, sR, Cp, 'liquid')
         s_sat_liquid_mass = S_sat_liquid_molar * np.reciprocal(M_L)
         S_entropy_mixture_molar = (
             1. - F_V) * S_sat_liquid_molar + F_V * S_sat_vapor_molar
         s_entropy_mixture_mass = (
             1. -
             F_V_mass) * s_sat_liquid_mass + F_V_mass * s_sat_vapor_mass
         H, h, S, s = H_enthalpy_mixture_molar, h_enthalpy_mixture_mass, S_entropy_mixture_molar, s_entropy_mixture_mass
         if __name__ == '__main__':
             print('This @(p,T) falls into two phase region')
             print(
                 'The mixture\'s state is ELV with a vapor quality = %.3f [molar base]'
                 % F_V)
             print(
                 'The mixture\'s state is ELV with a vapor quality = %.3f [mass base]'
                 % F_V_mass)
             print('x [molar base] = ', x)
             print('y [molar base] = ', y)
             print('x_mass [mass base] = ', x_mass)
             print('y_mass [mass base] = ', y_mass)
             print(
                 '\n======\nThe mixture liquid/vapor with h = %.3e [J/ kmol]'
                 % H)
             print(
                 '\n======\nThe mixture liquid/vapor with s = %.3e [J/(kmol K)]'
                 % S)
             print(
                 'The mixture liquid/vapor with h_mass = %.3e [J/ kg] {mass base}'
                 % h)
             print(
                 'The mixture liquid/vapor with s_mass = %.3e [J/(kg K)] {mass base}'
                 % s)
     return F_V, h, s
Exemplo n.º 7
0
CompN = MM.shape[0]  #components number
Pbubble_store = np.zeros([LN, CN])  #matrix with LN lines and CN columns
# Sy_store = np.zeros([LN, CN])
# y_store = np.zeros([LN, 2 * CN])
'''
========================
    PUTTING TO RUN: with a for loop
========================
'''

for index_out, T in enumerate(T_list):
    for index, LC_mass in enumerate(LC_mass_list):
        logging.debug('LC mass concentration =======> ' + str(LC_mass))
        logging.debug('Temperatura =======> ' + str(T))
        z_mass = np.array([LC_mass, (1. - LC_mass)])
        z = Tools_Convert.convert_massfrac_TO_molarfrac(MM, z_mass)
        pBubble, y, Sy, counter = bubble_obj(T, z)
        Pbubble_store[index, index_out] = pBubble
        # Sy_store[index, index_out] = Sy
        # y_store[index, 2 * index_out:2 * index_out + 2] = y
        # print('%.2f \t %.2e \t %.5f' % (T, pBubble, Sy))
'''
=====================
        PLOTTING
=====================
'''
colors = ['r', 'b', 'k', 'y', 'm', 'c', 'g', 'lightgray']
markers = ['o', 'v', '<', '>', '.', 'p', 'P', 's', '*']

plt.title('Bubble Pressure of Mixture of ' + comp1.name + ' $versus$ ' +
          comp2.name + ' (Dados RefProp)')
Exemplo n.º 8
0
===================================
        @(PRESSURE, TEMPERATURE, GLOBAL MOLAR FRACTION): These are the conditions you are interested to evaluate 
===================================

LEGEND:
p: Interested pressure (evaluate the enthalpy for this pressure) [Pa]
T: Interested temperature (evaluate the enthalpy considering this isotherm) [K]
OCR: oil-circulation ratio [-]: it is a mass fraction of oil per total mass mixture
z_mass: global mass fraction 
z: global molar fraction
'''
p = 0.3e5  # <=============================== change here
T = (30. + 273.15)  # <=============================== change here
LC, base = 0.40, 'mass'  # <=============================== change here
zin = np.array([LC, (1. - LC)])
z, z_mass = Tools_Convert.frac_input(MM, zin, base)
'''
=======================================
         CREATING OBJECTS - [to a better identification, all objects' names are followed by "_obj"]
=======================================
'''
rr_obj = RachfordRice()
eos_obj = PengRobinsonEos(pC, Tc, AcF, omega_a, omega_b, kij)

michelsen_obj = Michelsen()
flash_obj = Flash(max_iter=50, tolerance=1.0e-13, print_statistics=False)
prop_obj = Properties(pC, Tc, AcF, omega_a, omega_b, kij)


def getting_the_results_from_FlashAlgorithm_main(p, T, pC, Tc, AcF, z):
    initial_K_values = calculate_K_values_wilson(p, T, pC, Tc, AcF)

A VISCOSIDADE DO REFRIGERANTE R134a É OBTIDO VIA CoolProp

A VISCOSIDADE DO ÓLEO É CALCULADA VIA EQUAÇÃO DA TESE DO BERTOLDI  (page 82)
'''



##############################################################
#Testes...Discutir com Prof Jader

(pC, Tc, AcF, MM, omega_a, omega_b, kij, Cp) = props
LC, base = 0.01/100, 'mass' # <=============================== change here
zin = np.array([LC, (1. - LC)])
xRe, xRe_mass = Tools_Convert.frac_input(MM, zin, base)



############################################################
#variables that are necessary to be imported

(angleVenturi_in, angleVenturi_out, ks, Ld, D, Dvt, ziv, zig, zfg, zfv) = pipe() 
Ac_pipe = Area(0.0)
(p_e, T_e, mdotL_e, fmR134a) = input_flow_data_function()
Gt = mdotL_e / Ac_pipe

#creating the object
FlowTools_obj = FlowTools_class(pC, Tc, AcF, omega_a, omega_b, kij, mdotL_e)

Exemplo n.º 10
0
def edo_2p(l, uph):
    '''
    t: independent variable \n
    uph: dependent variables (packed), i.e., uph = uph(t) \n
    return: EDO system with derivative of uph with dt, i.e., d(uph)dt
    '''

    global T_e, z, z_mass, ks, mdotL_e, MM, pR, TR, hR
    # unpack
    u, p, h = uph
    Ac = Area(l)
    rc = np.sqrt(Ac / np.pi)
    Dc = 2. * rc
    Gt = mdotL_e / Ac  # see that Gt = Gt(l)
    Gt2 = np.power(Gt, 2)
    # ======================================================================
    #                      find(T)                                         #
    # ======================================================================
    TI = 0.95 * T_e
    TS = 1.05 * T_e

    def find_temperature(temperature, pressure, molar_composition, enthalpy):
        _q, helv, _s = hsFv_obj(pressure, temperature, molar_composition)
        return helv - enthalpy

    try:
        T, converged = brentq(find_temperature,
                              TI,
                              TS,
                              args=(p, z, h),
                              xtol=1e-3,
                              full_output=True)
        if converged is False:
            raise Exception('Not converged' + str(converged))
    except Exception as msg_err:
        print('It has been difficult to find the roots ' + str(msg_err))

    try:
        q, is_stable, K_values_newton, _initial_K_values = flash(
            p, T, pC, Tc, AcF, z)
        if is_stable is False:
            x = z / (q * (K_values_newton - 1.) + 1.)
            y = K_values_newton * x
        else:
            q, y, x = 0.0, np.zeros_like(z), z
            raise Exception(' Quality q = ' + str(q))
    except Exception as new_err:
        print(
            'This mixture is stable yet! (q < 0.0)! Artificially q and y were set up to ZERO '
            + str(new_err))

    logging.warning('A mistura ainda Monofásica? = %s' % (is_stable))
    logging.warning('(T = %s ), (P = %s ), (i = %s) and (u = %s ) at l = %s ' %
                    (T, p, h, u, l))
    logging.warning('Vapor quality = ' + str(q))

    x_mass = Tools_Convert.convert_molarfrac_TO_massfrac(MM, x)

    # ======================================================================
    #                            area derivative                           #
    # ======================================================================
    dl = 1e-5
    avrg_A = (Ac + Area(l + dl)) / 2.
    dAdl = derivative(Area, l, dl)

    # ======================================================================
    #                      compressibility                                 #
    # ======================================================================

    def volTP_func(pressure,
                   temperature,
                   quality,
                   molar_weight,
                   liquid_molar_composition,
                   vapor_molar_composition,
                   density=twoPhase_models['density']):
        '''
        This function has been created to evaluate compressibility = (1 / volTP) * dvolTPdp \n
        Obs: negative signal is omitted here, but it is used ahead \n

        volTP: specific two-phase volume [m3/kg] according homogeneous model \n

        Return: volTP
        '''

        volL_local = flowtools_obj.specificVolumeLiquid_Wrap(
            pressure, temperature, molar_weight, liquid_molar_composition,
            density)
        volG_local = flowtools_obj.specificVolumGas(pressure, temperature,
                                                    molar_weight,
                                                    vapor_molar_composition)
        volTP = flowtools_obj.specificVolumeTwoPhase(quality, volG_local,
                                                     volL_local)
        return volTP

    dp = 1e-3
    avrg_volTP = (volTP_func(p, T, q, MM, x, y) +
                  volTP_func(p + dp, T, q, MM, x, y)) / 2.
    dvolTPdp = derivative(volTP_func, p, dp, args=(T, q, MM, x, y))
    compressibility = np.power(avrg_volTP, -1) * dvolTPdp

    # =====================================================================
    #            calculating dvolTPdh (eq. A.13 Thesis)                  #
    # =====================================================================

    def volL_func(refrigerant_molar_composition,
                  oil_molar_composition,
                  pressure,
                  temperature,
                  molar_weight,
                  density=twoPhase_models['density']):
        '''
        This function has been created to make possible evaluate dvolTPdh \n
        where dvolTPdh is the derivative of specific two-phase volume with enthalpy \n

        Actually, as eq. A.13 shows, volL is part of dvolTPdh evaluation \n

        volL: specific volume of liquid-phase [m3/kg] \n

        Return: volL
        '''
        liquid_molar_composition = np.array(
            [refrigerant_molar_composition, oil_molar_composition])
        volL = flowtools_obj.specificVolumeLiquid_Wrap(
            pressure, temperature, molar_weight, liquid_molar_composition,
            density)

        return volL

    dxR = 1e-2
    xR, xO = x
    dvolLdxR = derivative(volL_func, xR, dxR, args=(xO, p, T, MM))
    logging.warning('derivada dvolLdxR = ' + str(dvolLdxR))

    def hL_func(refrigerant_molar_composition,
                oil_molar_composition,
                feed_molar_composition,
                pressure,
                temperature,
                pR,
                TR,
                hR,
                Cp,
                molar_weight,
                fluid_type='saturated_liquid'):
        '''
        This function has been created to make possible evaluate dvolTPdh \n
        where dvolTPdh is the derivative of specific two-phase volume with enthalpy \n
        xR: it´s a float
        xO: it's a float
        hL: saturated liquid phase [J/kg] (be careful with this unit...is not [J/kmol]) \n

        Return: hL
        '''
        liquid_molar_composition = np.array(
            [refrigerant_molar_composition, oil_molar_composition])
        H_L_local = prop_obj.calculate_enthalpy(TR, temperature, pR, pressure,
                                                liquid_molar_composition,
                                                feed_molar_composition, hR, Cp,
                                                fluid_type)
        M_L_local = prop_obj.calculate_weight_molar_mixture(
            molar_weight, liquid_molar_composition, fluid_type)
        hL = H_L_local / M_L_local
        return hL

    dhLdxR = derivative(hL_func,
                        xR,
                        dxR,
                        args=(xO, z, p, T, pR, TR, hR, Cp, MM))

    volL = flowtools_obj.specificVolumeLiquid_Wrap(p, T, MM, x,
                                                   twoPhase_models['density'])
    if y.all() == 0.0:
        volG, H_G, M_V, hG = np.zeros(4)
    else:
        volG = flowtools_obj.specificVolumGas(p, T, MM, y)
        H_G = prop_obj.calculate_enthalpy(TR, T, pR, p, y, z, hR, Cp,
                                          'saturated_vapor')
        M_V = prop_obj.calculate_weight_molar_mixture(MM, y, 'saturated_vapor')
        hG = H_G / M_V
    H_L = prop_obj.calculate_enthalpy(TR, T, pR, p, x, z, hR, Cp,
                                      'saturated_liquid')
    M_L = prop_obj.calculate_weight_molar_mixture(MM, x, 'saturated_liquid')
    hL = H_L / M_L
    vol_fg = volG - volL
    h_fg = hG - hL
    xR_mass, xO_mass = x_mass
    dvolTPdh = (vol_fg - xO_mass * dvolLdxR) / (h_fg - xO_mass * dhLdxR)
    logging.warning('vaporization enthalpy = ' + str(h_fg))
    logging.warning('derivada dhLdxR = ' + str(dhLdxR))
    logging.warning('dvolTPdh = ' + str(dvolTPdh))
    # ======================================================================
    #                      two-phase multiplier                            #
    # ======================================================================
    viscL_fo = flowtools_obj.viscosityLiquid_Wrap(p, T, z, z_mass,
                                                  twoPhase_models['viscosity'])
    volL_fo = flowtools_obj.specificVolumeLiquid_Wrap(
        p, T, MM, z, twoPhase_models['density'])
    viscL = flowtools_obj.viscosityLiquid_Wrap(p, T, x, x_mass,
                                               twoPhase_models['viscosity'])
    volTP = flowtools_obj.specificVolumeTwoPhase(q, volG, volL)
    viscTP = flowtools_obj.viscosityTwoPhase(q, volG, volTP, viscL,
                                             twoPhase_models['viscosityTP'])
    phiLO2 = flowtools_obj.twoPhaseMultiplier(q, viscTP, viscL, volG, volL)
    logging.warning('\n rho_fo = %s' % (1. / volL_fo))
    logging.warning('\n volTP = %s' % volTP)
    logging.warning('\n mu_fo = %s' % (viscL_fo * 1e6))
    # logging.warning('\n mu_L = %s' % (viscL * 1e6))
    # logging.warning('\n mu_bif = %s' % (viscTP * 1e6))
    logging.warning('\n Multiplicador Bifasico = %s' % phiLO2)
    # ======================================================================
    #                      friction factor f_LO                            #
    # ======================================================================
    Re_mon = flowtools_obj.reynolds_function(Gt, Dc, viscL_fo)
    f_FLO = flowtools_obj.frictionFactorFanning_Wrap(
        Re_mon, ks, Dc, twoPhase_models['friction'])
    logging.warning('\n Re_fo = %s <---> Fanning_fo = %s' % (Re_mon, f_FLO))

    # ======================================================================
    #                      setting matrix's coefficients                 #
    # ======================================================================
    A11, A12, A13 = np.power(u, -1), -compressibility, -(dvolTPdh / volTP)
    A21, A22, A23 = u, volTP, 0.
    A31, A32, A33 = u, 0., 1.

    aux = -volTP * phiLO2 * (2.0 * Gt2 * volL_fo * (f_FLO / Dc))
    C1, C2, C3 = (-dAdl / avrg_A), aux, aux
    # ======================================================================
    #                      matrix solving                                  #
    # ======================================================================
    matrizA = np.array([[A11, A12, A13], [A21, A22, A23], [A31, A32, A33]])
    RHS_C = np.array([C1, C2, C3])
    dudl, dpdl, dhdl = np.linalg.solve(matrizA, RHS_C)
    return np.array([dudl, dpdl, dhdl])  #array shape (3,)