Source code for ht.condensation

# -*- coding: utf-8 -*-
'''Chemical Engineering Design Library (ChEDL). Utilities for process modeling.
Copyright (C) 2016, Caleb Bell <Caleb.Andrew.Bell@gmail.com>

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from __future__ import division
from math import pi, sin
from fluids.constants import g, R
from fluids.core import Reynolds, Prandtl
from ht.conv_internal import turbulent_Dittus_Boelter

__all__ = ['Boyko_Kruzhilin', 'Nusselt_laminar', 'h_kinetic',
           'Akers_Deans_Crosser', 'Cavallini_Smith_Zecchin', 'Shah']


[docs]def Nusselt_laminar(Tsat, Tw, rhog, rhol, kl, mul, Hvap, L, angle=90.): r'''Calculates heat transfer coefficient for laminar film condensation of a pure chemical on a flat plate, as presented in [1]_ according to an analysis performed by Nusselt in 1916. .. math:: h=0.943\left[\frac{g\sin(\theta)\rho_{liq}(\rho_l-\rho_v)k_{l}^3 \Delta H_{vap}}{\mu_l(T_{sat}-T_w)L}\right]^{0.25} Parameters ---------- Tsat : float Saturation temperature at operating pressure [Pa] Tw : float Wall temperature, [K] rhog : float Density of the gas [kg/m^3] rhol : float Density of the liquid [kg/m^3] kl : float Thermal conductivity of liquid [W/m/K] mul : float Viscosity of liquid [Pa*s] Hvap : float Heat of vaporization of the fluid at P, [J/kg] L : float Length of the plate [m] angle : float, optional Angle of inclination of the plate [degrees] Returns ------- h : float Heat transfer coefficient [W/m^2/K] Notes ----- Optionally, the plate may be inclined. The constant 0.943 is actually: .. math:: 2\sqrt{2}/3 Examples -------- p. 578 in [1]_, matches exactly. >>> Nusselt_laminar(Tsat=370, Tw=350, rhog=7.0, rhol=585., kl=0.091, ... mul=158.9E-6, Hvap=776900, L=0.1) 1482.206403453679 References ---------- .. [1] Hewitt, G. L. Shires T. Reg Bott G. F., George L. Shires, and T. R. Bott. Process Heat Transfer. 1E. Boca Raton: CRC Press, 1994. ''' return 2.*2.**0.5/3.*(kl**3*rhol*(rhol - rhog)*g*sin(angle/180.*pi) *Hvap/(mul*(Tsat - Tw)*L))**0.25
[docs]def Boyko_Kruzhilin(m, rhog, rhol, kl, mul, Cpl, D, x): r'''Calculates heat transfer coefficient for condensation of a pure chemical inside a vertical tube or tube bundle, as presented in [2]_ according to [1]_. .. math:: h_f = h_{LO}\left[1 + x\left(\frac{\rho_L}{\rho_G} - 1\right)\right]^{0.5} .. math:: h_{LO} = 0.021 \frac{k_L}{L} Re_{LO}^{0.8} Pr^{0.43} Parameters ---------- m : float Mass flow rate [kg/s] rhog : float Density of the gas [kg/m^3] rhol : float Density of the liquid [kg/m^3] kl : float Thermal conductivity of liquid [W/m/K] mul : float Viscosity of liquid [Pa*s] Cpl : float Constant-pressure heat capacity of liquid [J/kg/K] D : float Diameter of the tubing [m] x : float Quality at the specific interval [-] Returns ------- h : float Heat transfer coefficient [W/m^2/K] Notes ----- To calculate overall heat transfer coefficient during condensation, simply average values at x = 1 and x = 0. Examples -------- Page 589 in [2]_, matches exactly. >>> Boyko_Kruzhilin(m=500*pi/4*.03**2, rhog=6.36, rhol=582.9, kl=0.098, ... mul=159E-6, Cpl=2520., D=0.03, x=0.85) 10598.657227479956 References ---------- .. [1] Boyko, L. D., and G. N. Kruzhilin. "Heat Transfer and Hydraulic Resistance during Condensation of Steam in a Horizontal Tube and in a Bundle of Tubes." International Journal of Heat and Mass Transfer 10, no. 3 (March 1, 1967): 361-73. doi:10.1016/0017-9310(67)90152-4. .. [2] Hewitt, G. L. Shires T. Reg Bott G. F., George L. Shires, and T. R. Bott. Process Heat Transfer. 1E. Boca Raton: CRC Press, 1994. ''' Vlo = m/rhol/(pi/4.*D**2) Relo = rhol*Vlo*D/mul Prl = mul*Cpl/kl hlo = 0.021*kl/D*Relo**0.8*Prl**0.43 return hlo*(1. + x*(rhol/rhog - 1.))**0.5
[docs]def Akers_Deans_Crosser(m, rhog, rhol, kl, mul, Cpl, D, x): r'''Calculates heat transfer coefficient for condensation of a pure chemical inside a vertical tube or tube bundle, as presented in [2]_ according to [1]_. .. math:: Nu = \frac{hD_i}{k_l} = C Re_e^n Pr_l^{1/3} .. math:: C = 0.0265, n=0.8 \text{ for } Re_e > 5\times10^4 .. math:: C = 5.03, n=\frac{1}{3} \text{ for } Re_e < 5\times10^4 .. math:: Re_e = \frac{D_i G_e}{\mu_l} .. math:: G_e = G\left[(1-x)+x(\rho_l/\rho_g)^{0.5}\right] Parameters ---------- m : float Mass flow rate [kg/s] rhog : float Density of the gas [kg/m^3] rhol : float Density of the liquid [kg/m^3] kl : float Thermal conductivity of liquid [W/m/K] mul : float Viscosity of liquid [Pa*s] Cpl : float Constant-pressure heat capacity of liquid [J/kg/K] D : float Diameter of the tubing [m] x : float Quality at the specific interval [-] Returns ------- h : float Heat transfer coefficient [W/m^2/K] Notes ----- Examples -------- >>> Akers_Deans_Crosser(m=0.35, rhog=6.36, rhol=582.9, kl=0.098, ... mul=159E-6, Cpl=2520., D=0.03, x=0.85) 7117.24177265201 References ---------- .. [1] Akers, W. W., H. A. Deans, and O. K. Crosser. "Condensing Heat Transfer Within Horizontal Tubes." Chem. Eng. Progr. Vol: 55, Symposium Ser. No. 29 (January 1, 1959). .. [2] Kakaç, Sadik, ed. Boilers, Evaporators, and Condensers. 1st. Wiley-Interscience, 1991. ''' G = m/(pi/4*D**2) Ge = G*((1-x) + x*(rhol/rhog)**0.5) Ree = D*Ge/mul Prl = mul*Cpl/kl if Ree > 5E4: C, n = 0.0265, 0.8 else: C, n = 5.03, 1/3. Nu = C*Ree**n*Prl**(1/3.) return Nu*kl/D
#print([Akers_Deans_Crosser(m=0.01, rhog=6.36, rhol=582.9, kl=0.098, mul=159E-6, Cpl=2520., D=0.03, x=0.85)])
[docs]def h_kinetic(T, P, MW, Hvap, f=1.0): r'''Calculates heat transfer coefficient for condensation of a pure chemical inside a vertical tube or tube bundle, as presented in [2]_ according to [1]_. .. math:: h = \left(\frac{2f}{2-f}\right)\left(\frac{MW}{1000\cdot 2\pi R T} \right)^{0.5}\left(\frac{H_{vap}^2 P \cdot MW}{1000\cdot RT^2}\right) Parameters ---------- T : float Vapor temperature, [K] P : float Vapor pressure, [Pa] MW : float Molecular weight of the gas, [g/mol] Hvap : float Heat of vaporization of the fluid at P, [J/kg] f : float Correction factor, [-] Returns ------- h : float Heat transfer coefficient [W/m^2/K] Notes ----- f is a correction factor for how the removal of gas particles affects the behavior of the ideal gas in diffusing to the condensing surface. It is quite close to one, and has not been well explored in the literature due to the rarity of the importance of the kinetic resistance. Examples -------- Water at 1 bar and 300 K: >>> h_kinetic(300, 1E5, 18.02, 2441674) 30788829.908851154 References ---------- .. [1] Berman, L. D. "On the Effect of Molecular-Kinetic Resistance upon Heat Transfer with Condensation." International Journal of Heat and Mass Transfer 10, no. 10 (October 1, 1967): 1463. doi:10.1016/0017-9310(67)90033-6. .. [2] Kakaç, Sadik, ed. Boilers, Evaporators, and Condensers. 1 edition. Wiley-Interscience, 1991. .. [3] Stephan, Karl. Heat Transfer in Condensation and Boiling. Translated by C. V. Green. Softcover reprint of the original 1st ed. 1992 edition. Berlin; New York: Springer, 2013. ''' return (2*f)/(2-f)*(MW/(1000*2*pi*R*T))**0.5*(Hvap**2*P*MW)/(1000*R*T**2)
[docs]def Cavallini_Smith_Zecchin(m, x, D, rhol, rhog, mul, mug, kl, Cpl): r'''Calculates heat transfer coefficient for condensation of a fluid inside a tube, as presented in [1]_, also given in [2]_ and [3]_. .. math:: Nu = \frac{hD_i}{k_l} = 0.05 Re_e^{0.8} Pr_l^{0.33} .. math:: Re_{eq} = Re_g(\mu_g/\mu_l)(\rho_l/\rho_g)^{0.5} + Re_l .. math:: v_{gs} = \frac{mx}{\rho_g \frac{\pi}{4}D^2} .. math:: v_{ls} = \frac{m(1-x)}{\rho_l \frac{\pi}{4}D^2} Parameters ---------- m : float Mass flow rate [kg/s] x : float Quality at the specific interval [-] D : float Diameter of the channel [m] rhol : float Density of the liquid [kg/m^3] rhog : float Density of the gas [kg/m^3] mul : float Viscosity of liquid [Pa*s] mug : float Viscosity of gas [Pa*s] kl : float Thermal conductivity of liquid [W/m/K] Cpl : float Constant-pressure heat capacity of liquid [J/kg/K] Returns ------- h : float Heat transfer coefficient [W/m^2/K] Notes ----- Examples -------- >>> Cavallini_Smith_Zecchin(m=1, x=0.4, D=.3, rhol=800, rhog=2.5, mul=1E-5, mug=1E-3, kl=0.6, Cpl=2300) 5578.218369177804 References ---------- .. [1] A. Cavallini, J. R. Smith and R. Zecchin, A dimensionless correlation for heat transfer in forced convection condensation, 6th International Heat Transfer Conference., Tokyo, Japan (1974) 309-313. .. [2] Kakaç, Sadik, ed. Boilers, Evaporators, and Condensers. 1st. Wiley-Interscience, 1991. .. [3] Balcılar, Muhammet, Ahmet Selim Dalkılıç, Berna Bolat, and Somchai Wongwises. "Investigation of Empirical Correlations on the Determination of Condensation Heat Transfer Characteristics during Downward Annular Flow of R134a inside a Vertical Smooth Tube Using Artificial Intelligence Algorithms." Journal of Mechanical Science and Technology 25, no. 10 (October 12, 2011): 2683-2701. doi:10.1007/s12206-011-0618-2. ''' Prl = Prandtl(Cp=Cpl, mu=mul, k=kl) Vl = m*(1-x)/(rhol*pi/4*D**2) Vg = m*x/(rhog*pi/4*D**2) Rel = Reynolds(V=Vl, D=D, rho=rhol, mu=mul) Reg = Reynolds(V=Vg, D=D, rho=rhog, mu=mug) '''The following was coded, and may be used instead of the above lines, to check that the definitions of parameters here provide the same results as those defined in [1]_. G = m/(pi/4*D**2) Re = G*D/mul Rel = Re*(1-x) Reg = Re*x/(mug/mul)''' Reeq = Reg*(mug/mul)*(rhol/rhog)**0.5 + Rel Nul = 0.05*Reeq**0.8*Prl**0.33 return Nul*kl/D # confirmed to be with respect to the liquid
[docs]def Shah(m, x, D, rhol, mul, kl, Cpl, P, Pc): r'''Calculates heat transfer coefficient for condensation of a fluid inside a tube, as presented in [1]_ and again by the same author in [2]_; also given in [3]_. Requires no properties of the gas. Uses the Dittus-Boelter correlation for single phase heat transfer coefficient, with a Reynolds number assuming all the flow is liquid. .. math:: h_{TP} = h_L\left[(1-x)^{0.8} +\frac{3.8x^{0.76}(1-x)^{0.04}} {P_r^{0.38}}\right] Parameters ---------- m : float Mass flow rate [kg/s] x : float Quality at the specific interval [-] D : float Diameter of the channel [m] rhol : float Density of the liquid [kg/m^3] mul : float Viscosity of liquid [Pa*s] kl : float Thermal conductivity of liquid [W/m/K] Cpl : float Constant-pressure heat capacity of liquid [J/kg/K] P : float Pressure of the fluid, [Pa] Pc : float Critical pressure of the fluid, [Pa] Returns ------- h : float Heat transfer coefficient [W/m^2/K] Notes ----- [1]_ is well written an unambiguous as to how to apply this equation. Examples -------- >>> Shah(m=1, x=0.4, D=.3, rhol=800, mul=1E-5, kl=0.6, Cpl=2300, P=1E6, Pc=2E7) 2561.2593415479214 References ---------- .. [1] Shah, M. M. "A General Correlation for Heat Transfer during Film Condensation inside Pipes." International Journal of Heat and Mass Transfer 22, no. 4 (April 1, 1979): 547-56. doi:10.1016/0017-9310(79)90058-9. .. [2] Shah, M. M., Heat Transfer During Film Condensation in Tubes and Annuli: A Review of the Literature, ASHRAE Transactions, vol. 87, no. 3, pp. 1086-1100, 1981. .. [3] Kakaç, Sadik, ed. Boilers, Evaporators, and Condensers. 1st. Wiley-Interscience, 1991. ''' VL = m/(rhol*pi/4*D**2) ReL = Reynolds(V=VL, D=D, rho=rhol, mu=mul) Prl = Prandtl(Cp=Cpl, k=kl, mu=mul) hL = turbulent_Dittus_Boelter(ReL, Prl)*kl/D Pr = P/Pc return hL*((1-x)**0.8 + 3.8*x**0.76*(1-x)**0.04/Pr**0.38)