Pipeline Simulation Guide

Comprehensive documentation for pipeline simulation in NeqSim, covering all pipeline types, common interface, flow modeling, and integration with mechanical design.

Overview
Pipeline Interface
Pipeline Types
Common Functionality
Flow Regime Detection
Heat Transfer
Pressure Drop Calculations
Profile Methods
Geometry and Properties
Mechanical Design Integration
Examples

Overview

NeqSim provides a unified pipeline simulation framework supporting:

Single-phase flow - Gas or liquid pipelines
Two-phase flow - Gas-liquid systems with holdup and slip
Multiphase flow - Gas-oil-water systems
Transient flow - Time-dependent simulations
Steady-state flow - Equilibrium calculations

All pipeline types implement the PipeLineInterface which provides 70+ common methods for consistent access to pipeline properties and behavior.

Location: neqsim.process.equipment.pipeline

Pipeline Interface

All pipeline classes implement PipeLineInterface, providing a consistent API:

public interface PipeLineInterface extends ProcessEquipmentInterface {
    // Geometry
    void setDiameter(double diameter);
    double getDiameter();
    void setLength(double length);
    double getLength();
    void setRoughness(double roughness);
    double getRoughness();
    void setAngle(double angle);
    double getAngle();
    void setElevationChange(double elevation);
    double getElevationChange();
    void setWallThickness(double thickness);
    double getWallThickness();
    
    // Flow Properties
    double getVelocity();
    double getVelocity(String unit);
    double getSuperficialVelocity();
    double getReynoldsNumber();
    double getFrictionFactor();
    double getFlowRegime();
    String getFlowRegimeDescription();
    
    // Pressure Drop
    double getPressureDrop();
    double getPressureDrop(String unit);
    double getTotalPressureDrop();
    double getFrictionalPressureDrop();
    double getGravitationalPressureDrop();
    double getAccelerationalPressureDrop();
    
    // Two-Phase Properties
    double getLiquidHoldup();
    double getGasVoidFraction();
    double getSlipRatio();
    double getMixtureVelocity();
    double getLiquidSuperficialVelocity();
    double getGasSuperficialVelocity();
    
    // Heat Transfer
    void setOverallHeatTransferCoefficient(double U);
    double getOverallHeatTransferCoefficient();
    void setAmbientTemperature(double temp);
    double getAmbientTemperature();
    double getHeatLoss();
    double getHeatLoss(String unit);
    
    // Profile Data
    double[] getPressureProfile();
    double[] getTemperatureProfile();
    double[] getLiquidHoldupProfile();
    double[] getVelocityProfile();
    int getNumberOfNodes();
    void setNumberOfNodes(int nodes);
    
    // Mechanical Design
    MechanicalDesign getMechanicalDesign();
    void initMechanicalDesign();
}

Pipeline Types

PipeBeggsAndBrills

Two-phase flow using Beggs-Brill correlation with flow regime detection.

import neqsim.process.equipment.pipeline.PipeBeggsAndBrills;

PipeBeggsAndBrills pipe = new PipeBeggsAndBrills("Flowline", inlet);
pipe.setLength(5000.0, "m");
pipe.setDiameter(0.254, "m");  // 10 inch
pipe.setAngle(5.0);  // Upward inclination
pipe.run();

// Flow regime
String regime = pipe.getFlowRegimeDescription();  // "Intermittent", "Segregated", etc.
double holdup = pipe.getLiquidHoldup();

AdiabaticPipe

Simple pipe with no heat transfer (adiabatic walls).

import neqsim.process.equipment.pipeline.AdiabaticPipe;

AdiabaticPipe pipe = new AdiabaticPipe("Gas Pipe", inlet);
pipe.setLength(1000.0, "m");
pipe.setDiameter(0.3, "m");
pipe.run();

// Temperature remains constant
double dT = pipe.getOutletStream().getTemperature("C") 
          - pipe.getInletStream().getTemperature("C");
// dT ≈ 0 (adiabatic)

OnePhasePipe

Optimized for single-phase (gas or liquid) flow.

import neqsim.process.equipment.pipeline.OnePhasePipe;

OnePhasePipe pipe = new OnePhasePipe("Liquid Line", inlet);
pipe.setLength(2000.0, "m");
pipe.setDiameter(0.15, "m");
pipe.run();

double reynolds = pipe.getReynoldsNumber();
double friction = pipe.getFrictionFactor();

MultiphasePipe

Wrapper for TwoPhasePipeFlowSystem with full multiphase capabilities.

import neqsim.process.equipment.pipeline.MultiphasePipe;

MultiphasePipe pipe = new MultiphasePipe("Export Pipeline", inlet);
pipe.setLength(50000.0, "m");
pipe.setDiameter(0.4, "m");
pipe.setNumberOfNodes(100);
pipe.setOverallHeatTransferCoefficient(15.0, "W/m2K");
pipe.setAmbientTemperature(4.0, "C");
pipe.run();

// Get profiles
double[] pressure = pipe.getPressureProfile();
double[] temperature = pipe.getTemperatureProfile();
double[] holdup = pipe.getLiquidHoldupProfile();

TransientPipe

Time-dependent pipeline simulation.

import neqsim.process.equipment.pipeline.TransientPipe;

TransientPipe pipe = new TransientPipe("Transient Line", inlet);
pipe.setLength(10000.0, "m");
pipe.setDiameter(0.3, "m");
pipe.setTimeStep(1.0);  // seconds
pipe.setSimulationTime(3600.0);  // 1 hour
pipe.run();

// Access time-dependent results
double[][] pressureVsTime = pipe.getPressureHistory();

Common Functionality

Setting Geometry

All pipeline types support consistent geometry methods:

// Length
pipe.setLength(5000.0, "m");
pipe.setLength(16404.0, "ft");

// Diameter
pipe.setDiameter(0.254, "m");      // Outer diameter
pipe.setInnerDiameter(0.244, "m"); // Inner diameter

// Wall thickness
pipe.setWallThickness(0.01, "m");  // 10mm

// Roughness
pipe.setRoughness(0.0001, "m");    // Absolute roughness
pipe.setRoughness(0.1, "mm");      // With unit

// Elevation
pipe.setElevationChange(100.0, "m");  // Total rise
pipe.setAngle(5.7);                   // Degrees from horizontal

Getting Flow Properties

// Velocity
double velocity = pipe.getVelocity("m/s");
double superficial = pipe.getSuperficialVelocity();

// Pressure drop
double totalDP = pipe.getTotalPressureDrop();
double frictionDP = pipe.getFrictionalPressureDrop();
double gravityDP = pipe.getGravitationalPressureDrop();
double accelDP = pipe.getAccelerationalPressureDrop();

// Dimensionless numbers
double Re = pipe.getReynoldsNumber();
double f = pipe.getFrictionFactor();

Two-Phase Properties

// Holdup and void fraction
double holdup = pipe.getLiquidHoldup();      // Liquid volume fraction
double voidFrac = pipe.getGasVoidFraction(); // Gas volume fraction

// Superficial velocities
double vsl = pipe.getLiquidSuperficialVelocity();
double vsg = pipe.getGasSuperficialVelocity();
double vm = pipe.getMixtureVelocity();

// Slip ratio
double slip = pipe.getSlipRatio();  // vg/vl

Flow Regime Detection

The Beggs-Brill correlation identifies flow regimes:

Regime	Description	Typical Conditions
Segregated	Stratified flow, liquid at bottom	Low gas, low liquid velocity
Intermittent	Slug/plug flow	Moderate velocities
Distributed	Annular/mist flow	High gas velocity
Transition	Between regimes	Boundary conditions

PipeBeggsAndBrills pipe = new PipeBeggsAndBrills("Pipe", inlet);
pipe.setLength(1000.0, "m");
pipe.setDiameter(0.2, "m");
pipe.run();

// Get flow regime
int regimeCode = pipe.getFlowRegime();
String regimeDesc = pipe.getFlowRegimeDescription();

switch (regimeCode) {
    case 1: System.out.println("Segregated flow"); break;
    case 2: System.out.println("Intermittent flow"); break;
    case 3: System.out.println("Distributed flow"); break;
    case 4: System.out.println("Transition"); break;
}

Flow Pattern Map

The Beggs-Brill flow pattern boundaries are defined by:

$L_1 = 316 \cdot \lambda_L^{0.302}$ $L_2 = 0.0009252 \cdot \lambda_L^{-2.4684}$ $L_3 = 0.10 \cdot \lambda_L^{-1.4516}$ $L_4 = 0.5 \cdot \lambda_L^{-6.738}$

Where $\lambda_L$ is the no-slip liquid holdup and $N_{Fr}$ is the Froude number.

Heat Transfer

Overall Heat Transfer Coefficient

// Set U-value
pipe.setOverallHeatTransferCoefficient(25.0, "W/m2K");
pipe.setOverallHeatTransferCoefficient(4.4, "BTU/hr-ft2-F");

// Set ambient conditions
pipe.setAmbientTemperature(15.0, "C");
pipe.setAmbientTemperature(4.0, "C");  // Seabed

// Calculate heat loss
pipe.run();
double heatLoss = pipe.getHeatLoss("kW");
double heatLossMW = pipe.getHeatLoss("MW");

Typical U-Values

Application	U-Value (W/m²K)
Bare pipe in air	10-25
Insulated pipe in air	1-5
Buried pipe	2-10
Subsea pipe (uninsulated)	15-50
Subsea pipe (insulated)	1-5
Pipe-in-pipe	0.5-2

Pressure Drop Calculations

Total Pressure Drop

\[\Delta P_{total} = \Delta P_{friction} + \Delta P_{gravity} + \Delta P_{acceleration}\]

Frictional Pressure Drop (Beggs-Brill)

\[\Delta P_{friction} = \frac{f_{tp} \cdot \rho_{ns} \cdot v_m^2}{2 \cdot D} \cdot L\]

Where:

$f_{tp}$ = two-phase friction factor
$\rho_{ns}$ = no-slip mixture density
$v_m$ = mixture velocity
$D$ = pipe diameter
$L$ = pipe length

Gravitational Pressure Drop

\[\Delta P_{gravity} = \rho_s \cdot g \cdot \sin(\theta) \cdot L\]

Where:

$\rho_s$ = slip mixture density = $\rho_L \cdot H_L + \rho_g \cdot (1-H_L)$
$H_L$ = liquid holdup
$\theta$ = pipe inclination angle

Liquid Holdup Correlation

\[H_L(\theta) = H_L(0) \cdot \psi\]

Where $\psi$ is the inclination correction factor.

Profile Methods

For pipelines divided into multiple nodes:

MultiphasePipe pipe = new MultiphasePipe("Pipeline", inlet);
pipe.setLength(50000.0, "m");
pipe.setNumberOfNodes(100);
pipe.run();

// Pressure profile
double[] pressure = pipe.getPressureProfile();

// Temperature profile
double[] temperature = pipe.getTemperatureProfile();

// Liquid holdup profile
double[] holdup = pipe.getLiquidHoldupProfile();

// Velocity profile
double[] velocity = pipe.getVelocityProfile();

// Plot profiles
for (int i = 0; i < pipe.getNumberOfNodes(); i++) {
    double distance = i * pipe.getLength() / pipe.getNumberOfNodes();
    System.out.printf("%.0f m: P=%.1f bar, T=%.1f°C, HL=%.2f%n",
        distance, pressure[i], temperature[i], holdup[i]);
}

Geometry and Properties

Standard Pipe Sizes (API 5L)

NPS (inch)	OD (mm)	OD (m)
2”	60.3	0.0603
4”	114.3	0.1143
6”	168.3	0.1683
8”	219.1	0.2191
10”	273.1	0.2731
12”	323.9	0.3239
16”	406.4	0.4064
20”	508.0	0.5080
24”	609.6	0.6096
30”	762.0	0.7620
36”	914.4	0.9144
42”	1066.8	1.0668
48”	1219.2	1.2192

Mechanical Design Integration

All pipeline types integrate with the mechanical design framework:

// Initialize mechanical design
AdiabaticPipe pipe = new AdiabaticPipe("Export Line", inlet);
pipe.setLength(50000.0, "m");
pipe.setDiameter(0.508, "m");
pipe.initMechanicalDesign();

// Configure design
PipelineMechanicalDesign design = (PipelineMechanicalDesign) pipe.getMechanicalDesign();
design.setMaxOperationPressure(150.0);  // bara
design.setMaxOperationTemperature(80.0);  // °C
design.setMaterialGrade("X65");
design.setDesignStandardCode("DNV-OS-F101");
design.setCompanySpecificDesignStandards("Equinor");

// Calculate design
design.calcDesign();

// Get results
double wallThickness = design.getWallThickness();  // mm
String json = design.toJson();  // Complete report

See Pipeline Mechanical Design for detailed mechanical design documentation.

Examples

Example 1: Gas Export Pipeline

import neqsim.thermo.system.SystemSrkEos;
import neqsim.process.equipment.stream.Stream;
import neqsim.process.equipment.pipeline.AdiabaticPipe;

// Dry gas
SystemSrkEos gas = new SystemSrkEos(303.15, 150.0);
gas.addComponent("methane", 0.92);
gas.addComponent("ethane", 0.05);
gas.addComponent("propane", 0.02);
gas.addComponent("CO2", 0.01);
gas.setMixingRule("classic");

Stream inlet = new Stream("Gas Inlet", gas);
inlet.setFlowRate(20.0, "MSm3/day");
inlet.run();

// 100 km pipeline
AdiabaticPipe pipeline = new AdiabaticPipe("Export Pipeline", inlet);
pipeline.setLength(100000.0, "m");
pipeline.setDiameter(0.762, "m");  // 30 inch
pipeline.setRoughness(0.0001, "m");
pipeline.run();

System.out.println("Inlet: " + inlet.getPressure("bara") + " bara");
System.out.println("Outlet: " + pipeline.getOutletStream().getPressure("bara") + " bara");
System.out.println("Pressure drop: " + pipeline.getPressureDrop("bara") + " bara");
System.out.println("Velocity: " + pipeline.getVelocity("m/s") + " m/s");

Example 2: Subsea Multiphase Flowline

import neqsim.process.equipment.pipeline.MultiphasePipe;

// Wellstream
SystemSrkEos fluid = new SystemSrkEos(350.0, 200.0);
fluid.addComponent("methane", 0.65);
fluid.addComponent("ethane", 0.08);
fluid.addComponent("propane", 0.05);
fluid.addComponent("n-hexane", 0.10);
fluid.addComponent("n-decane", 0.10);
fluid.addComponent("water", 0.02);
fluid.setMixingRule("classic");
fluid.setMultiPhaseCheck(true);

Stream wellhead = new Stream("Wellhead", fluid);
wellhead.setFlowRate(50000.0, "kg/hr");
wellhead.run();

// 25 km subsea flowline
MultiphasePipe flowline = new MultiphasePipe("Subsea Flowline", wellhead);
flowline.setLength(25000.0, "m");
flowline.setDiameter(0.254, "m");  // 10 inch
flowline.setNumberOfNodes(50);
flowline.setOverallHeatTransferCoefficient(15.0, "W/m2K");
flowline.setAmbientTemperature(4.0, "C");
flowline.run();

// Results
System.out.println("Outlet pressure: " + flowline.getOutletStream().getPressure("bara") + " bara");
System.out.println("Outlet temperature: " + flowline.getOutletStream().getTemperature("C") + " °C");
System.out.println("Liquid holdup: " + flowline.getLiquidHoldup());
System.out.println("Flow regime: " + flowline.getFlowRegimeDescription());
System.out.println("Heat loss: " + flowline.getHeatLoss("MW") + " MW");

Example 3: Vertical Riser

import neqsim.process.equipment.pipeline.PipeBeggsAndBrills;

// Production from seabed
Stream production = new Stream("Seabed Production", wellfluid);
production.setFlowRate(30000.0, "kg/hr");
production.run();

// 500m riser
PipeBeggsAndBrills riser = new PipeBeggsAndBrills("Riser", production);
riser.setLength(550.0, "m");  // Include catenary
riser.setDiameter(0.2, "m");
riser.setElevationChange(500.0, "m");  // Vertical rise
riser.run();

System.out.println("Bottom pressure: " + production.getPressure("bara") + " bara");
System.out.println("Top pressure: " + riser.getOutletStream().getPressure("bara") + " bara");
System.out.println("Flow regime: " + riser.getFlowRegimeDescription());
System.out.println("Liquid holdup: " + riser.getLiquidHoldup());

Example 4: Pipeline with Mechanical Design

// Create pipeline
AdiabaticPipe pipe = new AdiabaticPipe("Gas Pipeline", inlet);
pipe.setLength(50000.0, "m");
pipe.setDiameter(0.508, "m");
pipe.run();

// Mechanical design
pipe.initMechanicalDesign();
PipelineMechanicalDesign design = (PipelineMechanicalDesign) pipe.getMechanicalDesign();
design.setMaxOperationPressure(150.0);
design.setMaterialGrade("X65");
design.setDesignStandardCode("ASME-B31.8");
design.setLocationClass("Class 2");
design.calcDesign();

// Get design results
System.out.println("Wall thickness: " + design.getWallThickness() + " mm");
System.out.println("MAOP: " + design.getCalculator().getMAOP("bar") + " bar");
System.out.println("Test pressure: " + design.getCalculator().calculateTestPressure() + " MPa");

// Cost estimation
design.getCalculator().calculateProjectCost();
System.out.println("Total cost: $" + design.getCalculator().getTotalProjectCost());

// Full JSON report
String json = design.toJson();

Pipeline Mechanical Design - Wall thickness, stress analysis, cost estimation
Mechanical Design Standards - ASME, DNV, API standards
Fluid Mechanics - Detailed flow modeling
Valves - Flow control devices
Equipment Index - All equipment types

Pipeline Simulation Guide

Comprehensive Java library for thermodynamic, physical property, and process simulation. NeqSim provides tools for PVT analysis, phase equilibria, transport properties, and full process simulation.

Pipeline Simulation Guide

Table of Contents

Overview

Pipeline Interface

Pipeline Types

PipeBeggsAndBrills

AdiabaticPipe

OnePhasePipe

MultiphasePipe

TransientPipe

Common Functionality

Setting Geometry

Getting Flow Properties

Two-Phase Properties

Flow Regime Detection

Flow Pattern Map

Heat Transfer

Overall Heat Transfer Coefficient

Typical U-Values

Pressure Drop Calculations

Total Pressure Drop

Frictional Pressure Drop (Beggs-Brill)

Gravitational Pressure Drop

Liquid Holdup Correlation

Profile Methods

Geometry and Properties

Standard Pipe Sizes (API 5L)

Mechanical Design Integration

Examples

Example 1: Gas Export Pipeline

Example 2: Subsea Multiphase Flowline

Example 3: Vertical Riser

Example 4: Pipeline with Mechanical Design

Pipeline Simulation Guide

Table of Contents

Overview

Pipeline Interface

Pipeline Types

PipeBeggsAndBrills

AdiabaticPipe

OnePhasePipe

MultiphasePipe

TransientPipe

Common Functionality

Setting Geometry

Getting Flow Properties

Two-Phase Properties

Flow Regime Detection

Flow Pattern Map

Heat Transfer

Overall Heat Transfer Coefficient

Typical U-Values

Pressure Drop Calculations

Total Pressure Drop

Frictional Pressure Drop (Beggs-Brill)

Gravitational Pressure Drop

Liquid Holdup Correlation

Profile Methods

Geometry and Properties

Standard Pipe Sizes (API 5L)

Mechanical Design Integration

Examples

Example 1: Gas Export Pipeline

Example 2: Subsea Multiphase Flowline

Example 3: Vertical Riser

Example 4: Pipeline with Mechanical Design

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