carbatpy.models.components.two_phase_correlations

Submodules

• carbatpy.models.components.two_phase_correlations.base_class_two_phase
• carbatpy.models.components.two_phase_correlations.heat_transfer_correlations
• carbatpy.models.components.two_phase_correlations.pressure_loss_correlations

Classes

DengHTC	Condensation heat-transfer coefficient – Deng et al. (2019).
MQTPressureDrop	Frictional pressure drop for evaporation – Moreno-Quibén & Thome (2007),
MacdonaldPressureDrop	Macdonald et al. two-phase frictional pressure-drop correlation.
FangPressureDrop	DISCLAIMER: ERROR IN PAPER? RESULTS IN INPLAUSIBLE PRESSURE LOSSES. CONTACTED AUTHORS.

Package Contents

class carbatpy.models.components.two_phase_correlations.DengHTC(D, G, T_wall, CT_type, state, fluid)

Bases: HeatTransferBase

Condensation heat-transfer coefficient – Deng et al. (2019).

Extends TwoPhaseBase with: - Log-mean void fraction (α) and Rouhani–Axelsson void fraction (α_ra) - Bell–Ghaly mixture correction - HTC for annular and stratified-wavy regimes

Parameters:

• D (float – inner tube diameter [m])

• G (float – mass flux [kg/(m² s)])

• T_wall (float – wall temperature [K])

• CT_type (str – "HC" (hydrocarbon) or other (affects J_G^T constant))

• state (FluidState)

• fluid (carbatpy Fluid object)

T_wall

CT_type

calc()

Condensation HTC – Deng et al. (2019).

Returns:

dict with keys

Return type:

alpha [W/(m²K)], meta

class carbatpy.models.components.two_phase_correlations.MQTPressureDrop(D, G, state, fluid, heat_transfer_rate=None)

Bases: PressureLossBase

Frictional pressure drop for evaporation – Moreno-Quibén & Thome (2007), with Wojtan–Ursenbacher–Thome (2005) flow map.

Parameters:

• D (float – inner tube diameter [m])

• G (float – mass flux [kg/(m² s)])

• state (FluidState)

• fluid (carbatpy Fluid object)

heat_transfer_rate = None

calc()

Frictional pressure drop Δp_f per meter.

Parameters (set in __init__)

heat_transfer_rate : float, optional – heat flux [W/m²]; required for D/M regime

returns:

dict with keys

rtype:

dp_fric, dpdl, regime, meta

class carbatpy.models.components.two_phase_correlations.MacdonaldPressureDrop(D, G, state, fluid)

Bases: PressureLossBase

Macdonald et al. two-phase frictional pressure-drop correlation.

Parameters:

• D (float – inner tube diameter [m])

• G (float – mass flux [kg/(m² s)])

• state (FluidState)

• fluid (carbatpy Fluid object)

calc()

Returns frictional pressure gradient [Pa/m].

class carbatpy.models.components.two_phase_correlations.FangPressureDrop(state, fluid, mdot, D, eps=0.0)

Bases: PressureLossBase

DISCLAIMER: ERROR IN PAPER? RESULTS IN INPLAUSIBLE PRESSURE LOSSES. CONTACTED AUTHORS. Frictional pressure drop for condensation – Fang et al. (2025), Int. J. Refrigeration 170, 214–223.

Parameters:

• state (FluidState)

• fluid (carbatpy Fluid object)

• mdot (float – mass flow rate [kg/s])

• D (float – inner tube diameter [m])

mdot

eps = 0.0

calc()

Total frictional pressure drop over the pipe. Uses self.eps (roughness [m]) set in __init__.

Returns:

dict with keys

Return type:

dp_fric, meta