Mass Transfer API Documentation

This document provides comprehensive API documentation for NeqSim’s enhanced mass transfer model for two-phase pipe flow, including detailed method descriptions, parameters, examples, and literature references.

Overview
MassTransferConfig
InterfacialAreaCalculator
MassTransferCoefficientCalculator
TwoPhaseFixedStaggeredGridSolver Extensions
Complete Examples
Literature References

Overview

The mass transfer model provides tools for simulating interphase mass transfer in two-phase pipe flow, including:

Evaporation: Liquid components transferring to gas phase
Dissolution: Gas components dissolving into liquid phase
Complete phase transitions: Handling total evaporation or dissolution
Three-phase systems: Gas-oil-water configurations

Architecture

TwoPhaseFixedStaggeredGridSolver
    ├── MassTransferConfig (configuration parameters)
    └── FlowNode.getFluidBoundary()
            └── KrishnaStandartFilmModel
                    ├── InterfacialAreaCalculator (interfacial area)
                    └── MassTransferCoefficientCalculator (kL, kG)

MassTransferConfig

Configuration class for mass transfer calculations with user-configurable parameters.

Package: neqsim.fluidmechanics.flowsolver.twophaseflowsolver.twophasepipeflowsolver

Factory Methods

Method	Description	Use Case
`MassTransferConfig()`	Default configuration	General two-phase flow
`MassTransferConfig.forEvaporation()`	Optimized for evaporation	Complete liquid evaporation
`MassTransferConfig.forDissolution()`	Optimized for dissolution	Complete gas dissolution
`MassTransferConfig.forThreePhase()`	Three-phase systems	Gas-oil-water
`MassTransferConfig.forHighAccuracy()`	Research/validation	High-fidelity simulations

Configuration Parameters

Transfer Limits

Parameter	Default	Description	Valid Range
`maxTransferFractionBidirectional`	0.9	Max fraction transferable in bidirectional mode	0.1 - 0.99
`maxTransferFractionDirectional`	0.5	Max fraction transferable in directional modes	0.1 - 0.99
`useAdaptiveLimiting`	true	Enable Courant-like adaptive limiting	true/false

Convergence

Parameter	Default	Description	Valid Range
`convergenceTolerance`	1e-4	Tolerance for mass transfer calculations	> 1e-10
`maxIterations`	100	Maximum solver iterations	≥ 10
`minIterations`	5	Minimum iterations before convergence check	≥ 1

Stability

Parameter	Default	Description	Valid Range
`minMolesFraction`	1e-15	Minimum mole fraction threshold	≥ 1e-20
`absoluteMinMoles`	1e-20	Absolute minimum moles	≥ 1e-30
`maxTemperatureChangePerNode`	50.0 K	Max temperature change per node	≥ 1.0 K
`maxPhaseDepletionPerNode`	0.95	Max phase fraction that can deplete per node	0.5 - 0.99
`allowPhaseDisappearance`	true	Allow complete phase disappearance	true/false

Model Options

Parameter	Default	Description	Reference
`includeMarangoniEffect`	false	Surface tension gradient correction	Springer & Pigford (1970)
`includeEntrainment`	true	Droplet entrainment in annular flow	Ishii & Mishima (1989)
`includeWaveEnhancement`	true	Wave enhancement for stratified flow	Tzotzi & Andritsos (2013)
`includeTurbulenceEffects`	true	Turbulence enhancement of kL	Lamont & Scott (1970)
`coupledHeatMassTransfer`	true	Iterative heat-mass coupling	-
`coupledIterations`	10	Outer iterations for coupling	≥ 1

Three-Phase Options

Parameter	Default	Description
`enableThreePhase`	false	Enable three-phase mass transfer
`aqueousPhaseIndex`	2	Index of aqueous phase
`organicPhaseIndex`	1	Index of oil/organic phase

Diagnostics

Parameter	Default	Description
`enableDiagnostics`	false	Enable convergence logging
`detectStalls`	true	Detect convergence stalls
`stallDetectionWindow`	5	Iterations for stall detection

Example: Configure for Evaporation

import neqsim.fluidmechanics.flowsolver.twophaseflowsolver.twophasepipeflowsolver.MassTransferConfig;

// Use factory method
MassTransferConfig config = MassTransferConfig.forEvaporation();

// Or customize manually
MassTransferConfig customConfig = new MassTransferConfig();
customConfig.setMaxTransferFractionBidirectional(0.85);
customConfig.setMaxPhaseDepletionPerNode(0.98);
customConfig.setAllowPhaseDisappearance(true);
customConfig.setIncludeWaveEnhancement(true);
customConfig.setCoupledHeatMassTransfer(true);
customConfig.setEnableDiagnostics(true);

Example: Configure for Three-Phase

MassTransferConfig config = MassTransferConfig.forThreePhase();
// Verify phase indices match your system
config.setAqueousPhaseIndex(2);  // Water phase
config.setOrganicPhaseIndex(1);  // Oil phase
config.setConvergenceTolerance(1e-5);  // Tighter tolerance

InterfacialAreaCalculator

Utility class for calculating interfacial area per unit volume (m²/m³ = 1/m) in two-phase flow.

Package: neqsim.fluidmechanics.flownode

Flow Pattern Models

Flow Pattern	Model	Formula/Approach
STRATIFIED	Flat interface	a = Si/A, chord length at interface
STRATIFIED_WAVY	Flat + wave enhancement	Kelvin-Helmholtz instability
ANNULAR	Film interface	a = 4/(D·√(1-αL))
ANNULAR + entrainment	Film + droplets	Ishii & Mishima (1989)
SLUG	Taylor bubble + slug	Weighted average
BUBBLE	Sauter mean diameter	a = 6·αG/d32
DROPLET	Weber number criterion	a = 6·αL/d32
CHURN	Annular + bubble blend	Intermediate

Core Methods

`calculateInterfacialArea`

Calculates interfacial area for standard flow patterns.

public static double calculateInterfacialArea(
    FlowPattern flowPattern,  // Flow regime
    double diameter,          // Pipe diameter (m)
    double liquidHoldup,      // Liquid holdup (0-1)
    double rhoG,              // Gas density (kg/m³)
    double rhoL,              // Liquid density (kg/m³)
    double usg,               // Superficial gas velocity (m/s)
    double usl,               // Superficial liquid velocity (m/s)
    double sigma              // Surface tension (N/m)
)
// Returns: interfacial area per unit volume (1/m)

Example:

import neqsim.fluidmechanics.flownode.InterfacialAreaCalculator;
import neqsim.fluidmechanics.flownode.FlowPattern;

double diameter = 0.1;      // 100 mm pipe
double liquidHoldup = 0.3;  // 30% liquid
double rhoG = 50.0;         // kg/m³
double rhoL = 800.0;        // kg/m³
double usg = 5.0;           // m/s
double usl = 0.5;           // m/s
double sigma = 0.025;       // N/m

double area = InterfacialAreaCalculator.calculateInterfacialArea(
    FlowPattern.STRATIFIED_WAVY, diameter, liquidHoldup, 
    rhoG, rhoL, usg, usl, sigma);

System.out.println("Interfacial area: " + area + " m²/m³");
// Expected: ~10-50 m²/m³ for stratified wavy

Enhanced Methods

`calculateStratifiedWavyArea`

Calculates stratified wavy area with Kelvin-Helmholtz wave enhancement.

public static double calculateStratifiedWavyArea(
    double diameter,          // Pipe diameter (m)
    double liquidHoldup,      // Liquid holdup (0-1)
    double usg,               // Superficial gas velocity (m/s)
    double usl,               // Superficial liquid velocity (m/s)
    double rhoG,              // Gas density (kg/m³)
    double rhoL,              // Liquid density (kg/m³)
    double sigma              // Surface tension (N/m)
)
// Returns: interfacial area with wave enhancement (1/m)

Physics:

Checks Kelvin-Helmholtz instability criterion
Critical velocity: Vcrit = √(σ·Δρ·g / (ρG·ρL))
Wave amplitude estimation when Vrel > Vcrit
Enhancement factor capped at 3.5× (literature recommendation)

Reference: Tzotzi, C., Andritsos, N. (2013). Interfacial shear stress in wavy stratified gas-liquid flow. Chemical Engineering Science, 86, 49-57.

Example:

double areaWavy = InterfacialAreaCalculator.calculateStratifiedWavyArea(
1,     // diameter
25,    // liquidHoldup  
0,     // usg (high velocity for waves)
3,     // usl
0,    // rhoG
0,   // rhoL
020    // sigma
);
// Expect enhancement factor 1.5-3.5× compared to flat stratified

`calculateAnnularAreaWithEntrainment`

Calculates annular flow area including entrained droplets.

public static double calculateAnnularAreaWithEntrainment(
    double diameter,          // Pipe diameter (m)
    double liquidHoldup,      // Liquid holdup (0-1)
    double rhoG,              // Gas density (kg/m³)
    double rhoL,              // Liquid density (kg/m³)
    double usg,               // Superficial gas velocity (m/s)
    double muL,               // Liquid viscosity (Pa·s)
    double sigma              // Surface tension (N/m)
)
// Returns: interfacial area with entrainment (1/m)

Physics:

Gas Weber number: WeG = ρG·usg²·D/σ
Entrainment fraction: E = tanh(7.25e-7·WeG^1.25·ReL^0.25)
Droplet Sauter diameter: d32/D = 0.069·WeG^(-0.5)
Total area = film area + droplet area

Reference: Ishii, M., Mishima, K. (1989). Droplet entrainment correlation in annular two-phase flow. Int. J. Heat Mass Transfer, 32(10), 1835-1846.

Example:

double areaAnnular = InterfacialAreaCalculator.calculateAnnularAreaWithEntrainment(
05,      // diameter (50 mm)
05,      // liquidHoldup (thin film)
0,      // rhoG (high pressure gas)
0,     // rhoL
0,      // usg (high velocity)
001,     // muL
015      // sigma
);
// Expect significant contribution from entrained droplets at high WeG

`calculateEnhancedInterfacialArea`

Comprehensive method with all enhancement options.

public static double calculateEnhancedInterfacialArea(
    FlowPattern flowPattern,
    double diameter,
    double liquidHoldup,
    double rhoG,
    double rhoL,
    double usg,
    double usl,
    double muL,
    double sigma,
    boolean includeWaveEnhancement,
    boolean includeEntrainment
)
// Returns: interfacial area with selected enhancements (1/m)

Validation Methods

`getExpectedInterfacialAreaRange`

Returns literature-based expected ranges for validation.

public static double[] getExpectedInterfacialAreaRange(
    FlowPattern flowPattern,
    double diameter
)
// Returns: [min, typical, max] interfacial area (1/m)

Expected Ranges by Flow Pattern:

Flow Pattern	Min	Typical	Max
Stratified	2/D	5/D	15/D
Annular	8/D	50/D	300/D
Slug	5/D	30/D	100/D
Bubble	50	200	1000
Droplet	100	500	2000
Churn	20/D	80/D	200/D

Example: Validate Calculation

FlowPattern pattern = FlowPattern.STRATIFIED_WAVY;
double D = 0.1;

double calculatedArea = InterfacialAreaCalculator.calculateInterfacialArea(
    pattern, D, 0.3, 50, 800, 5, 0.5, 0.025);

double[] expected = InterfacialAreaCalculator.getExpectedInterfacialAreaRange(pattern, D);
System.out.printf("Calculated: %.1f m²/m³%n", calculatedArea);
System.out.printf("Expected range: %.1f - %.1f m²/m³%n", expected[0], expected[2]);

if (calculatedArea >= expected[0] && calculatedArea <= expected[2]) {
    System.out.println("✓ Within literature range");
} else {
    System.out.println("⚠ Outside expected range - verify inputs");
}

MassTransferCoefficientCalculator

Utility class for calculating mass transfer coefficients (kL, kG) in two-phase pipe flow.

Package: neqsim.fluidmechanics.flownode

Core Correlations

Correlation	Application	Formula
Dittus-Boelter	Turbulent pipe flow	Sh = 0.023·Re^0.8·Sc^0.33
Ranz-Marshall	Spheres (bubbles/droplets)	Sh = 2 + 0.6·Re^0.5·Sc^0.33
Solbraa	Stratified gas-liquid	Flow-pattern specific
Vivian-Peaceman	Falling film	Sh = 0.0096·Re^0.87·Sc^0.5

Liquid-Side Methods

`calculateLiquidMassTransferCoefficient`

Standard liquid-side mass transfer coefficient.

public static double calculateLiquidMassTransferCoefficient(
    FlowPattern flowPattern,  // Flow regime
    double diameter,          // Pipe diameter (m)
    double liquidHoldup,      // Liquid holdup (0-1)
    double usg,               // Superficial gas velocity (m/s)
    double usl,               // Superficial liquid velocity (m/s)
    double rhoL,              // Liquid density (kg/m³)
    double muL,               // Liquid viscosity (Pa·s)
    double diffL              // Liquid diffusivity (m²/s)
)
// Returns: kL (m/s), always ≥ 0

Example:

import neqsim.fluidmechanics.flownode.MassTransferCoefficientCalculator;

double kL = MassTransferCoefficientCalculator.calculateLiquidMassTransferCoefficient(
    FlowPattern.STRATIFIED,
    0.1,      // diameter (m)
    0.3,      // liquidHoldup
    5.0,      // usg (m/s)
    0.5,      // usl (m/s)
    800.0,    // rhoL (kg/m³)
    0.001,    // muL (Pa·s)
    2e-9      // diffL (m²/s) - typical for gas in liquid
);

System.out.printf("kL = %.2e m/s%n", kL);
// Expected: 1e-5 to 2e-4 m/s for stratified flow

`calculateLiquidMassTransferCoefficientWithTurbulence`

Enhanced kL with turbulence correction.

public static double calculateLiquidMassTransferCoefficientWithTurbulence(
    FlowPattern flowPattern,
    double diameter,
    double liquidHoldup,
    double usg,
    double usl,
    double rhoL,
    double muL,
    double diffL,
    double turbulentIntensity  // Turbulent intensity (0-1, typical 0.05-0.2)
)
// Returns: enhanced kL (m/s)

Physics: Enhancement factor = 1 + 2.5·Tu·√Re
Capped at 5× enhancement (literature limit)

Reference: Lamont, J.C., Scott, D.S. (1970). An eddy cell model of mass transfer into the surface of a turbulent liquid. AIChE Journal, 16(4), 513-519.

Example:

double turbulentIntensity = 0.15;  // 15% turbulence

double kL_enhanced = MassTransferCoefficientCalculator
    .calculateLiquidMassTransferCoefficientWithTurbulence(
        FlowPattern.SLUG,  // High turbulence flow pattern
        0.1, 0.4, 3.0, 1.0, 800.0, 0.001, 2e-9,
        turbulentIntensity);

// Compare to base
double kL_base = MassTransferCoefficientCalculator
    .calculateLiquidMassTransferCoefficient(
        FlowPattern.SLUG, 0.1, 0.4, 3.0, 1.0, 800.0, 0.001, 2e-9);

System.out.printf("Base kL: %.2e m/s%n", kL_base);
System.out.printf("Enhanced kL: %.2e m/s%n", kL_enhanced);
System.out.printf("Enhancement factor: %.2f×%n", kL_enhanced / kL_base);

`applyMarangoniCorrection`

Corrects kL for surface-active components.

public static double applyMarangoniCorrection(
    double kLBase,                // Base kL (m/s)
    double surfaceTensionGradient, // dσ/dc (N·m/mol)
    double diffL,                 // Liquid diffusivity (m²/s)
    double muL                    // Liquid viscosity (Pa·s)
)
// Returns: corrected kL (m/s)

Physics: Marangoni number: Ma = |dσ/dc|·D / (μ·kL²)
Correction: kL_corrected = kL / (1 + 0.35·√|Ma|)
Correction limited to 10× reduction

Reference: Springer, T.G., Pigford, R.L. (1970). Influence of surface turbulence and surfactants on gas transport through liquid interfaces. Ind. Eng. Chem. Fundam., 9(3), 458-465.

Example: Surfactant Effect

double kL_base = 1e-4;  // m/s
double dSigma_dC = 0.05;  // N·m/mol (strong surfactant)
double diffL = 2e-9;  // m²/s
double muL = 0.001;  // Pa·s

double kL_corrected = MassTransferCoefficientCalculator.applyMarangoniCorrection(
    kL_base, dSigma_dC, diffL, muL);

System.out.printf("Without surfactant: kL = %.2e m/s%n", kL_base);
System.out.printf("With surfactant: kL = %.2e m/s%n", kL_corrected);
System.out.printf("Reduction: %.0f%%%n", (1 - kL_corrected/kL_base) * 100);

Gas-Side Methods

`calculateGasMassTransferCoefficient`

Standard gas-side mass transfer coefficient.

public static double calculateGasMassTransferCoefficient(
    FlowPattern flowPattern,  // Flow regime
    double diameter,          // Pipe diameter (m)
    double liquidHoldup,      // Liquid holdup (0-1)
    double usg,               // Superficial gas velocity (m/s)
    double rhoG,              // Gas density (kg/m³)
    double muG,               // Gas viscosity (Pa·s)
    double diffG              // Gas diffusivity (m²/s)
)
// Returns: kG (m/s), always ≥ 0

Example:

double kG = MassTransferCoefficientCalculator.calculateGasMassTransferCoefficient(
    FlowPattern.STRATIFIED,
    0.1,       // diameter (m)
    0.3,       // liquidHoldup
    5.0,       // usg (m/s)
    50.0,      // rhoG (kg/m³)
    1.5e-5,    // muG (Pa·s)
    1e-5       // diffG (m²/s) - typical for gas-gas diffusion
);

System.out.printf("kG = %.2e m/s%n", kG);
// Expected: 1e-3 to 5e-2 m/s for stratified flow

Combined Methods

`calculateEnhancedLiquidMassTransferCoefficient`

Comprehensive calculation with all enhancement options.

public static double calculateEnhancedLiquidMassTransferCoefficient(
    FlowPattern flowPattern,
    double diameter,
    double liquidHoldup,
    double usg,
    double usl,
    double rhoL,
    double muL,
    double diffL,
    double turbulentIntensity,      // 0-1
    double surfaceTensionGradient,  // N·m/mol, 0 to disable
    boolean includeTurbulence,
    boolean includeMarangoni
)
// Returns: fully enhanced kL (m/s)

Example:

double kL_full = MassTransferCoefficientCalculator.calculateEnhancedLiquidMassTransferCoefficient(
    FlowPattern.ANNULAR,
    0.05,      // diameter
    0.1,       // liquidHoldup
    12.0,      // usg
    0.3,       // usl
    850.0,     // rhoL
    0.0008,    // muL
    1.5e-9,    // diffL
    0.12,      // turbulentIntensity
    0.02,      // surfaceTensionGradient
    true,      // includeTurbulence
    true       // includeMarangoni
);

Utility Methods

`estimateTurbulentIntensity`

Estimates turbulent intensity from flow pattern and Reynolds number.

public static double estimateTurbulentIntensity(
    FlowPattern flowPattern,
    double re                 // Reynolds number
)
// Returns: estimated turbulent intensity (0-1)

Typical Values:

Flow Pattern	Multiplier vs Base
Stratified	0.8×
Stratified Wavy	1.2×
Annular	1.5×
Slug	2.0×
Churn	2.5×
Bubble	1.8×

Where base Tu ≈ 0.16·Re^(-1/8) for developed turbulent flow.

Validation Methods

`getExpectedMassTransferCoefficientRange`

Returns literature-based expected ranges.

public static double[] getExpectedMassTransferCoefficientRange(
    FlowPattern flowPattern,
    int phase                 // 0 = gas, 1 = liquid
)
// Returns: [min, typical, max] (m/s)

`validateAgainstLiterature`

Checks if calculated value is within expected range.

public static boolean validateAgainstLiterature(
    double calculated,        // Calculated kL or kG
    FlowPattern flowPattern,
    int phase                 // 0 = gas, 1 = liquid
)
// Returns: true if within expected range

TwoPhaseFixedStaggeredGridSolver Extensions

New methods added to the solver for phase tracking and diagnostics.

Phase Tracking Methods

`isGasPhaseCompletelyDissolved`

Checks if gas phase has completely dissolved.

public boolean isGasPhaseCompletelyDissolved()
// Returns: true if gas phase has disappeared

`isLiquidPhaseCompletelyEvaporated`

Checks if liquid phase has completely evaporated.

public boolean isLiquidPhaseCompletelyEvaporated()
// Returns: true if liquid phase has disappeared

Summary Methods

`getMassTransferSummary`

Returns overall mass transfer statistics.

public double[] getMassTransferSummary()
// Returns: [totalDissolution, totalEvaporation, netTransfer] in moles

`getMassBalanceError`

Calculates mass balance closure error.

public double getMassBalanceError()
// Returns: relative mass balance error (should be < 0.01 for 1%)

Validation Methods

`validateMassTransferAgainstLiterature`

Generates validation report comparing to literature.

public String validateMassTransferAgainstLiterature()
// Returns: formatted validation report string

Complete Examples

Example 1: Water Evaporation into Dry Nitrogen

Simulating evaporation of water into flowing nitrogen gas.

import neqsim.thermo.system.SystemInterface;
import neqsim.thermo.system.SystemSrkEos;
import neqsim.processimulation.processequipment.stream.Stream;
import neqsim.fluidmechanics.flowsolver.twophaseflowsolver.twophasepipeflowsolver.*;

// Create fluid system
SystemInterface fluid = new SystemSrkEos(293.15, 1.01325);  // 20°C, 1 atm
fluid.addComponent("nitrogen", 0.95);
fluid.addComponent("water", 0.05);
fluid.setMixingRule("classic");
fluid.setMultiPhaseCheck(true);

// Create inlet stream
Stream inlet = new Stream("inlet", fluid);
inlet.setFlowRate(100.0, "kg/hr");
inlet.run();

// Configure mass transfer for evaporation
MassTransferConfig config = MassTransferConfig.forEvaporation();
config.setEnableDiagnostics(true);
config.setMaxPhaseDepletionPerNode(0.99);  // Allow near-complete evaporation

// Create pipe with mass transfer
// ... (pipe setup code)

// After simulation
System.out.println("Gas phase dissolved: " + solver.isGasPhaseCompletelyDissolved());
System.out.println("Liquid phase evaporated: " + solver.isLiquidPhaseCompletelyEvaporated());

double[] summary = solver.getMassTransferSummary();
System.out.printf("Total dissolved: %.4f mol%n", summary[0]);
System.out.printf("Total evaporated: %.4f mol%n", summary[1]);
System.out.printf("Net transfer: %.4f mol%n", summary[2]);

// Validate against literature
System.out.println(solver.validateMassTransferAgainstLiterature());

Example 2: CO₂ Dissolution into MEA Solution

CO₂ absorption in amine solvent.

import neqsim.fluidmechanics.flownode.*;

// Flow conditions
FlowPattern pattern = FlowPattern.ANNULAR;
double D = 0.025;          // 25 mm tube
double holdup = 0.15;      // Thin liquid film
double usg = 2.0;          // m/s
double usl = 0.1;          // m/s

// Fluid properties (MEA solution)
double rhoL = 1020.0;      // kg/m³
double muL = 0.002;        // Pa·s
double diffL = 1.5e-9;     // m²/s (CO2 in MEA)
double sigma = 0.050;      // N/m

// Calculate interfacial area
double area = InterfacialAreaCalculator.calculateAnnularAreaWithEntrainment(
    D, holdup, 50.0, rhoL, usg, muL, sigma);
System.out.printf("Interfacial area: %.1f m²/m³%n", area);

// Calculate mass transfer coefficient with enhancement
double turbulentIntensity = MassTransferCoefficientCalculator.estimateTurbulentIntensity(
    pattern, rhoL * usl * D / muL);
System.out.printf("Estimated turbulent intensity: %.3f%n", turbulentIntensity);

double kL = MassTransferCoefficientCalculator.calculateLiquidMassTransferCoefficientWithTurbulence(
    pattern, D, holdup, usg, usl, rhoL, muL, diffL, turbulentIntensity);
System.out.printf("kL: %.2e m/s%n", kL);

// Calculate volumetric mass transfer coefficient
double kLa = kL * area;
System.out.printf("kL·a: %.4f 1/s%n", kLa);

// Validate
double[] expectedKL = MassTransferCoefficientCalculator.getExpectedMassTransferCoefficientRange(
    pattern, 1);
System.out.printf("Expected kL range: %.2e - %.2e m/s%n", expectedKL[0], expectedKL[2]);

Example 3: Three-Phase Gas-Oil-Water System

// Configure for three-phase
MassTransferConfig config = MassTransferConfig.forThreePhase();
config.setAqueousPhaseIndex(2);   // Water
config.setOrganicPhaseIndex(1);   // Oil
config.setConvergenceTolerance(1e-5);
config.setCoupledIterations(15);
config.setEnableDiagnostics(true);

// Log configuration
System.out.println(config.toString());

Example 4: Literature Validation

import neqsim.fluidmechanics.flownode.*;

// Test case: Stratified flow, 100mm pipe
FlowPattern pattern = FlowPattern.STRATIFIED_WAVY;
double D = 0.1;

// Calculate and validate interfacial area
double area = InterfacialAreaCalculator.calculateInterfacialArea(
    pattern, D, 0.3, 50, 800, 5, 0.5, 0.025);
double[] areaRange = InterfacialAreaCalculator.getExpectedInterfacialAreaRange(pattern, D);

System.out.println("=== Interfacial Area Validation ===");
System.out.printf("Calculated: %.1f m²/m³%n", area);
System.out.printf("Literature range: %.1f - %.1f m²/m³%n", areaRange[0], areaRange[2]);
System.out.printf("Status: %s%n", 
    (area >= areaRange[0] && area <= areaRange[2]) ? "✓ PASS" : "✗ FAIL");

// Calculate and validate kL
double kL = MassTransferCoefficientCalculator.calculateLiquidMassTransferCoefficient(
    pattern, D, 0.3, 5, 0.5, 800, 0.001, 2e-9);
boolean kLValid = MassTransferCoefficientCalculator.validateAgainstLiterature(kL, pattern, 1);

System.out.println("\n=== Mass Transfer Coefficient Validation ===");
System.out.printf("Calculated kL: %.2e m/s%n", kL);
System.out.printf("Status: %s%n", kLValid ? "✓ PASS" : "✗ FAIL");

Literature References

Interfacial Area Correlations

Tzotzi, C., Andritsos, N. (2013)
Interfacial shear stress in wavy stratified gas-liquid flow.
Chemical Engineering Science, 86, 49-57.
Used for: Wave enhancement in stratified flow
Ishii, M., Mishima, K. (1989)
Droplet entrainment correlation in annular two-phase flow.
International Journal of Heat and Mass Transfer, 32(10), 1835-1846.
Used for: Entrainment in annular flow
Hewitt, G.F., Hall-Taylor, N.S. (1970)
Annular Two-Phase Flow.
Pergamon Press.
Used for: Annular flow interfacial area validation

Mass Transfer Coefficient Correlations

Lamont, J.C., Scott, D.S. (1970)
An eddy cell model of mass transfer into the surface of a turbulent liquid.
AIChE Journal, 16(4), 513-519.
Used for: Turbulence enhancement of kL
Springer, T.G., Pigford, R.L. (1970)
Influence of surface turbulence and surfactants on gas transport through liquid interfaces.
Industrial & Engineering Chemistry Fundamentals, 9(3), 458-465.
Used for: Marangoni effect correction
Solbraa, E. (2002)
Measurement and modelling of absorption of carbon dioxide into methyldiethanolamine solutions at high pressures.
PhD thesis, NTNU.
Used for: Stratified flow kL correlations and validation data

General References

Krishna, R., Standart, G.L. (1976)
Mass and energy transfer in multicomponent systems.
Chemical Engineering Communications, 3(4-5), 201-275.
Used for: Multicomponent diffusion theory
Taylor, R., Krishna, R. (1993)
Multicomponent Mass Transfer.
Wiley.
Used for: Film model theory
Perry’s Chemical Engineers’ Handbook, 8th Edition
Used for: Expected kL ranges and validation

Mass Transfer API Documentation

Table of Contents

Overview

Architecture

MassTransferConfig

Factory Methods

Configuration Parameters

Transfer Limits

Convergence

Stability

Model Options

Three-Phase Options

Diagnostics

Example: Configure for Evaporation

Example: Configure for Three-Phase

InterfacialAreaCalculator

Flow Pattern Models

Core Methods

calculateInterfacialArea

Enhanced Methods

calculateStratifiedWavyArea

calculateAnnularAreaWithEntrainment

calculateEnhancedInterfacialArea

Validation Methods

getExpectedInterfacialAreaRange

MassTransferCoefficientCalculator

Core Correlations

Liquid-Side Methods

calculateLiquidMassTransferCoefficient

calculateLiquidMassTransferCoefficientWithTurbulence

applyMarangoniCorrection

Gas-Side Methods

calculateGasMassTransferCoefficient

Combined Methods

calculateEnhancedLiquidMassTransferCoefficient

Utility Methods

estimateTurbulentIntensity

Validation Methods

getExpectedMassTransferCoefficientRange

validateAgainstLiterature

TwoPhaseFixedStaggeredGridSolver Extensions

Phase Tracking Methods

isGasPhaseCompletelyDissolved

isLiquidPhaseCompletelyEvaporated

Summary Methods

getMassTransferSummary

getMassBalanceError

Validation Methods

validateMassTransferAgainstLiterature

Complete Examples

Example 1: Water Evaporation into Dry Nitrogen

Example 2: CO₂ Dissolution into MEA Solution

Example 3: Three-Phase Gas-Oil-Water System

Example 4: Literature Validation

Literature References

Interfacial Area Correlations

Mass Transfer Coefficient Correlations

General References

See Also

`calculateInterfacialArea`

`calculateStratifiedWavyArea`

`calculateAnnularAreaWithEntrainment`

`calculateEnhancedInterfacialArea`

`getExpectedInterfacialAreaRange`

`calculateLiquidMassTransferCoefficient`

`calculateLiquidMassTransferCoefficientWithTurbulence`

`applyMarangoniCorrection`

`calculateGasMassTransferCoefficient`

`calculateEnhancedLiquidMassTransferCoefficient`

`estimateTurbulentIntensity`

`getExpectedMassTransferCoefficientRange`

`validateAgainstLiterature`

`isGasPhaseCompletelyDissolved`

`isLiquidPhaseCompletelyEvaporated`

`getMassTransferSummary`

`getMassBalanceError`

`validateMassTransferAgainstLiterature`