lib.heatTransfer module¶
- lib.heatTransfer.Nu_vertical_Churchill(Pr, Ra)[source]¶
Calculates Nusselt number for laminar and turbulent flows near a vertical surface with Churchill-Chu correlation [3]
\[Nu^{1/2} = 0.825 + \frac{0.387 Ra^{1/6}} {\left(1+(0.492/Pr)^{9/16}\right)^{8/27}}\]For laminar flow (Ra ≤ 10⁹) use this correlation with a slightly better accuracy
\[Nu = 0.68 + \frac{0.67 Ra^{1/4}} {\left(1+(0.492/Pr)^{9/16}\right)^{4/9}}\]The correlation originally developed for vertical flat surfaces can be too applied to vertical cylinders if this conditions is satisfied:
\[\frac{D}{L} \ge \frac{35}{Gr_L^{1/4}}\]- Parameters:
- Prfloat
Prandtl number [-]
- Rafloat
Rayleigh number [-]
- Returns:
- Nufloat
Nusselt number, [-]
Notes
This method does not exactly represent the behavior in the transition zone between laminar and turbulent flows (10⁸ ≤ Ra ≤ 20⁹), but its accuracy is enought for engineering applications in the entire range of Rayleigh numbers.
References
[1] VDI-Gesellschaft; VDI Heat Atlas 2nd Edition. Berlin, New York. Springer 2010.
[2] Bergman, T.L., Lavine, A.S., Incropera, F.P., DeWitt, D.P.; Introduction to Heat Transfer. 6th Ed.. Wiley, 2011.
[3] Churchill, S.W., Chu, H.H.S.; Correlating Equations for Laminar and Turbulent Free Convection from a Vertical Plate. Int. J. Heat Mass Transfer 18(11) (1975) 1323-29
Examples
From [1], Example 1, pag. 667
>>> print("%0.f" % Nu_vertical_Churchill(0.7, 9.26e8)) 120
From [2], Example 9.2, pag. 574:
>>> print("%0.f" % Nu_vertical_Churchill(0.69, 1.813E9)) 147
- lib.heatTransfer.h_tubeside_laminar_Eubank_Proctor(Gz, Gr, Pr, D, L)[source]¶
Coeficiente de transferencia de calor por calor sensible en el interior de tubos horizontales en regimen laminar Eubank, D. C. and Proctor W. S. - Effect of natural convection on heat transfer with laminar flow in tubes, MS Thesis, Chemical Engineering Department, Massachusetts Institute of Technology, 1951.
- lib.heatTransfer.h_tubeside_laminar_VDI(Re, Pr, D, L)[source]¶
Coeficiente de transferencia de calor por calor sensible en el interior de tubos horizontales en regimen laminar VDI Heat Atlas G1 Pag 695
- lib.heatTransfer.h_tubeside_laminar_Hausen(Gz)[source]¶
Coeficiente de transferencia de calor por calor sensible en el interior de tubos horizontales en regimen laminar Perry Capitulo 5 pag 15 0.1<Gz<1e4
- lib.heatTransfer.h_tubeside_laminar_Sieder_Tate(Gz, Gr)[source]¶
Coeficiente de transferencia de calor por calor sensible en el interior de tubos horizontales en regimen laminar Sieder and Tate - Heat Transfer and Pressure Drop of Liquids in Tubes, Industrial Engineering Chemistry, Vol. 28, p. 1429, 1936. Perry Capitulo 5 pag 15 Gz>100
- lib.heatTransfer.h_tubeside_turbulent_Sieder_Tate(Re, Pr)[source]¶
Coeficiente de transferencia de calor por calor sensible en el interior de tubos horizontales en regimen turbulento Sieder and Tate - Heat Transfer and Pressure Drop of Liquids in Tubes, Industrial Engineering Chemistry, Vol. 28, p. 1429, 1936. Re>10000 0.7<Pr<16700 L/D > 10
- lib.heatTransfer.h_tubeside_turbulent_Colburn(Re, Pr)[source]¶
Coeficiente de transferencia de calor por calor sensible en el interior de tubos horizontales en regimen turbulento DeltaT pequeña Re>10000 0.7<Pr<160 L/D > 10
- lib.heatTransfer.h_tubeside_turbulent_Dittus_Boelter(Re, Pr, calentamiento)[source]¶
Coeficiente de transferencia de calor por calor sensible en el interior de tubos horizontales en regimen turbulento DeltaT pequeña Re>10000 0.7<Pr<160 L/D > 10
- lib.heatTransfer.h_tubeside_turbulent_ESDU(Re, Pr)[source]¶
Coeficiente de transferencia de calor por calor sensible en el interior de tubos horizontales en regimen turbulento 40000<Re<1e6 0.3<Pr<300 L/D>60
- lib.heatTransfer.h_tubeside_turbulent_Gnielinski(Re, Pr, D, L)[source]¶
Coeficiente de transferencia de calor por calor sensible en el interior de tubos horizontales en regimen turbulento y de transición 3000<Re<5e6 0.5<Pr<2000 Serth - Process heat transfer_ principles and applications pag 63
- lib.heatTransfer.h_tubeside_turbulent_VDI(Re, Pr, filas_tubos, alineados)[source]¶
Coeficiente de transferencia de calor por calor sensible en el interior de tubos horizontales en regimen turbulento Re>10 Pr<600 alineados: indica si los tubos estan colocados en linea filas_tubos: numeros de filas de tubos
- lib.heatTransfer.h_anulli_Turbulent(Re, Pr, a, dhL=0, boundary=0)[source]¶
VDI Heat Atlas G2 Pag.703
- lib.heatTransfer.h_anulli_Transition(Re, Pr, a, dhL=0, boundary=0)[source]¶
VDI Heat Atlas G2 Pag.704
- lib.heatTransfer.Nu_Convection_Free_External_Horizontal_Plate(Pr, Ra)[source]¶
Calculo del Nusselt en convección natural externa de una pared horizontal
- lib.heatTransfer.efectividad(NTU, C_, flujo, **kwargs)[source]¶
Calculo de la efectividad del cambiador Flujo vendra definido por su acronimo
CF: Counter flow PF: Parallel flow CrFMix: Crossflow, both fluids mixed CrFSMix: Crossflow, one fluid mixed, other unmixed CrFunMix: Crossflow, both fluids unmixed 1-2TEMAE: 1-2 pass shell and tube exchanger
- kwargs: Opciones adicionales:
mixed: corriente mezclada para CrFSMix Cmin, Cmax
- lib.heatTransfer.TemperatureEffectiveness(NTU, R, flujo, **kwargs)[source]¶
Calculo de la temperatura efectividad del cambiador Flujo vendra definido por su acronimo
CF: Counter flow PF: Parallel flow CrFMix: Crossflow, both fluids mixed CrFSMix: Crossflow, one fluid mixed, other unmixed CrFunMix: Crossflow, both fluids unmixed 1-2TEMAE: 1-2 TEMA E 1-2TEMAE2: 1-2 TEMA E, shell fluid flow divided 1-3TEMAE: 1-3 TEMA E 1-4TEMAE: 1-4 TEMA E 1-1TEMAG: 1-1 TEMA G 1-2TEMAG: 1-2 TEMA G 1-1TEMAH: 1-1 TEMA H 1-2TEMAH: 1-2 TEMA H 1-1TEMAJ: 1-1 TEMA J 1-2TEMAJ: 1-2 TEMA J 1-4TEMAJ: 1-4 TEMA J
- kwargs: Opciones adicionales:
- mixed: corriente mezclada para CrFSMix
1, 2
- lib.heatTransfer.CorrectionFactor(P, R, flujo, **kwargs)[source]¶
Calculo de la factor de correccion Flujo vendra definido por su acronimo
CF: Counter flow PF: Parallel flow CrFMix: Crossflow, both fluids mixed CrFSMix: Crossflow, one fluid mixed, other unmixed CrFunMix: Crossflow, both fluids unmixed 1-2TEMAE: 1-2 pass shell and tube exchanger
- kwargs: Opciones adicionales:
- mixed: corriente mezclada para CrFSMix
Cmin, Cmax
- lib.heatTransfer.NTU_fPR(P, R, flujo, **kwargs)[source]¶
Calculo de la factor de correccion Flujo vendra definido por su acronimo
CF: Counter flow PF: Parallel flow CrFMix: Crossflow, both fluids mixed CrFSMix: Crossflow, one fluid mixed, other unmixed CrFunMix: Crossflow, both fluids unmixed 1-2TEMAE: 1-2 pass shell and tube exchanger
- kwargs: Opciones adicionales:
- mixed: corriente mezclada para CrFSMix
Cmin, Cmax
