Class Orifice

java.lang.Object

neqsim.util.NamedBaseClass

neqsim.process.SimulationBaseClass

neqsim.process.equipment.ProcessEquipmentBaseClass

neqsim.process.equipment.TwoPortEquipment

neqsim.process.equipment.diffpressure.Orifice

All Implemented Interfaces:

Serializable, Runnable, ProcessEquipmentInterface, TwoPortInterface, SimulationInterface, NamedInterface

public class Orifice
extends TwoPortEquipment

Orifice class for flow restriction and measurement using ISO 5167 orifice plate calculations.

This class supports both steady-state and transient/dynamic simulations. In transient mode, the orifice calculates flow based on the pressure differential across the plate using ISO 5167 equations, making it suitable for depressurization and blowdown scenarios.

Key features:

• ISO 5167 compliant flow calculations with Reader-Harris/Gallagher discharge coefficient
• Support for corner, flange, D and D/2 pressure taps
• Compressible flow with expansibility factor
• Pressure-driven flow in transient simulations (flow = f(ΔP))
• Automatic handling of zero/low flow conditions

Author:

ESOL

See Also:

• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
private Double	C
private Double	diameter
private Double	diameter_outer
private double	dischargeCoefficient
private Double	dp
private double	orificeDiameter
private double	pressureDownstream
private double	pressureUpstream
private static final long	serialVersionUID	Serialization version UID.

Fields inherited from class TwoPortEquipment

inStream, outStream

Fields inherited from class ProcessEquipmentBaseClass

conditionAnalysisMessage, energyStream, hasController, isSolved, properties, report

Fields inherited from class SimulationBaseClass

calcIdentifier, calculateSteadyState, time

Fields inherited from class NamedBaseClass

name

Constructor Summary

Constructors

Constructor	Description
Orifice(String name)	Constructor for Orifice.
Orifice(String name, double diameter, double orificeDiameter, double pressureUpstream, double pressureDownstream, double dischargeCoefficient)	Constructor for Orifice with full ISO 5167 parameters.

Method Summary

Modifier and Type	Method	Description
Double	calc_dp()	Calculate the non-recoverable pressure drop across the orifice.
static double	calculateBetaRatio(double D, double Do)	Calculates the diameter ratio (beta) of the orifice plate.
static double	calculateDischargeCoefficient(double D, double Do, double rho, double mu, double m, String taps)	Calculates the orifice discharge coefficient using the Reader-Harris Gallagher method.
static double	calculateExpansibility(double D, double Do, double P1, double P2, double k)	Calculates the expansibility factor for orifice plate calculations.
static double	calculateMassFlowRate(double D, double Do, double P1, double P2, double rho, double mu, double k, String taps)	Calculates the mass flow rate through an orifice plate using the ISO 5167 formulation.
static double	calculatePressureDrop(double D, double Do, double P1, double P2, double C)	Calculates the non-recoverable pressure drop across the orifice plate.
void	run(UUID uuid)	In this method all thermodynamic and unit operations will be calculated in a steady state calculation.
void	runTransient(double dt, UUID id)	Run transient simulation for the orifice.
void	setOrificeParameters(Double diameter, Double diameter_outer, Double C)	Deprecated. Use constructor parameters instead

Methods inherited from class TwoPortEquipment

getInletPressure, getInletStream, getInletTemperature, getMassBalance, getOutletPressure, getOutletStream, getOutletTemperature, setInletPressure, setInletStream, setInletTemperature, setOutletPressure, setOutletStream, setOutletTemperature, toJson, toJson, validateSetup

Methods inherited from class ProcessEquipmentBaseClass

copy, displayResult, equals, getConditionAnalysisMessage, getController, getEnergyStream, getEntropyProduction, getExergyChange, getMassBalance, getMechanicalDesign, getMinimumFlow, getPressure, getPressure, getProperty, getReport_json, getResultTable, getSpecification, getTemperature, getTemperature, getThermoSystem, hashCode, initMechanicalDesign, isActive, isActive, isSetEnergyStream, reportResults, run_step, runConditionAnalysis, setController, setEnergyStream, setEnergyStream, setFlowValveController, setMinimumFlow, setPressure, setRegulatorOutSignal, setSpecification, setTemperature, solved

Methods inherited from class SimulationBaseClass

getCalculateSteadyState, getCalculationIdentifier, getTime, increaseTime, isRunInSteps, setCalculateSteadyState, setCalculationIdentifier, setRunInSteps, setTime

Methods inherited from class NamedBaseClass

getName, getTagName, setName, setTagName

Methods inherited from class Object

clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface NamedInterface

getName, getTagName, setName, setTagName

Methods inherited from interface ProcessEquipmentInterface

getCapacityDuty, getCapacityMax, getExergyChange, getFluid, getRestCapacity, needRecalculation

Methods inherited from interface SimulationInterface

getCalculateSteadyState, getCalculationIdentifier, getTime, increaseTime, isRunInSteps, run, run_step, runTransient, setCalculateSteadyState, setCalculationIdentifier, setRunInSteps, setTime

Methods inherited from interface TwoPortInterface

getInStream, getOutStream

Field Details

serialVersionUID

private static final long serialVersionUID

Serialization version UID.

See Also:

• Constant Field Values

dp

private Double dp

diameter

private Double diameter

diameter_outer

private Double diameter_outer

C

private Double C

orificeDiameter

private double orificeDiameter

pressureUpstream

private double pressureUpstream

pressureDownstream

private double pressureDownstream

dischargeCoefficient

private double dischargeCoefficient

Constructor Details

Orifice

public Orifice(String name)

Constructor for Orifice.

Parameters:

name - a String object

Orifice

public Orifice(String name,
 double diameter,
 double orificeDiameter,
 double pressureUpstream,
 double pressureDownstream,
 double dischargeCoefficient)

Constructor for Orifice with full ISO 5167 parameters.

Creates an orifice plate flow restriction device with specified geometry and operating conditions. This constructor is typically used for transient/dynamic simulations where the orifice controls flow based on pressure differential.

Parameters:

name - Name of the orifice equipment

diameter - Upstream pipe internal diameter in meters

orificeDiameter - Orifice bore diameter in meters

pressureUpstream - Upstream design pressure in bara (used for reference)

pressureDownstream - Downstream boundary pressure in bara (e.g., flare header pressure). This value is used in transient simulations to establish the driving pressure differential.

dischargeCoefficient - Orifice discharge coefficient (typically 0.60-0.62 for sharp-edged orifices, or calculated using Reader-Harris/Gallagher method)

Method Details

setOrificeParameters

@Deprecated
public void setOrificeParameters(Double diameter,
 Double diameter_outer,
 Double C)

Deprecated.

Use constructor parameters instead

Set orifice parameters for legacy compatibility.

Note: These parameters are currently not used in the ISO 5167 calculations. Use the constructor with diameter, orificeDiameter, and dischargeCoefficient instead for transient simulations.

Parameters:

diameter - Orifice diameter

diameter_outer - Outer diameter

C - Discharge coefficient

calc_dp

public Double calc_dp()

Calculate the non-recoverable pressure drop across the orifice.

This method calculates the permanent pressure loss (deltaW) across an orifice plate, which represents the portion of pressure drop that is not recovered downstream. The calculation is based on the discharge coefficient and beta ratio.

Returns:

Non-recoverable pressure drop in bar

calculateDischargeCoefficient

public static double calculateDischargeCoefficient(double D,
 double Do,
 double rho,
 double mu,
 double m,
 String taps)

Calculates the orifice discharge coefficient using the Reader-Harris Gallagher method.

Parameters:

D - Upstream internal pipe diameter, in meters.

Do - Diameter of orifice at flow conditions, in meters.

rho - Density of fluid at P1, in kg/m^3.

mu - Viscosity of fluid at P1, in Pa*s.

m - Mass flow rate of fluid through the orifice, in kg/s.

taps - Tap type ("corner", "flange", "D", or "D/2").

Returns:

Discharge coefficient of the orifice.

calculateExpansibility

public static double calculateExpansibility(double D,
 double Do,
 double P1,
 double P2,
 double k)

Calculates the expansibility factor for orifice plate calculations.

Parameters:

D - Upstream internal pipe diameter, in meters.

Do - Diameter of orifice at flow conditions, in meters.

P1 - Static pressure of fluid upstream, in Pa.

P2 - Static pressure of fluid downstream, in Pa.

k - Isentropic exponent of fluid.

Returns:

Expansibility factor (1 for incompressible fluids).

calculatePressureDrop

public static double calculatePressureDrop(double D,
 double Do,
 double P1,
 double P2,
 double C)

Calculates the non-recoverable pressure drop across the orifice plate.

Parameters:

D - Upstream internal pipe diameter, in meters.

Do - Diameter of orifice at flow conditions, in meters.

P1 - Static pressure of fluid upstream, in Pa.

P2 - Static pressure of fluid downstream, in Pa.

C - Discharge coefficient.

Returns:

Non-recoverable pressure drop, in Pa.

calculateBetaRatio

public static double calculateBetaRatio(double D,
 double Do)

Calculates the diameter ratio (beta) of the orifice plate.

Parameters:

D - Upstream internal pipe diameter, in meters.

Do - Diameter of orifice at flow conditions, in meters.

Returns:

Diameter ratio (beta).

calculateMassFlowRate

public static double calculateMassFlowRate(double D,
 double Do,
 double P1,
 double P2,
 double rho,
 double mu,
 double k,
 String taps)

Calculates the mass flow rate through an orifice plate using the ISO 5167 formulation.

Inputs and output are all in SI units. The method iterates the Reader-Harris/Gallagher discharge coefficient until convergence.

Parameters:

D - upstream internal pipe diameter in meters

Do - orifice diameter in meters

P1 - upstream static pressure in Pa

P2 - downstream static pressure in Pa

rho - fluid density in kg/m3 at P1

mu - fluid viscosity in Pa*s at P1

k - isentropic exponent of the fluid

taps - pressure tap type ("corner", "flange", "D", or "D/2")

Returns:

mass flow rate in kg/s

run

public void run(UUID uuid)

In this method all thermodynamic and unit operations will be calculated in a steady state calculation.

Parameters:

uuid - UUID

runTransient

public void runTransient(double dt,
 UUID id)

Run transient simulation for the orifice.

In transient mode, the orifice acts as a pressure-driven flow restriction device. The flow rate through the orifice is calculated based on the pressure differential using ISO 5167 equations:

m = A × C × ε × √(2ρΔP / (1 - β⁴))

where:

• A = orifice area (m²)
• C = discharge coefficient
• ε = expansibility factor (accounts for compressibility)
• ρ = fluid density at inlet (kg/m³)
• ΔP = pressure drop across orifice (Pa)
• β = diameter ratio (d/D)

The downstream pressure is taken from the stored pressureDownstream value if available (e.g., flare header pressure), otherwise it reads from the outlet stream. This ensures proper flow calculation even when stream pressures aren't updated in the flow network.

Important: In dynamic simulations, the orifice DETERMINES the flow rate based on available ΔP. This is different from steady-state mode where flow may be specified upstream. The calculated flow is set on both the thermoSystem and inStream to ensure consistency in the process network.

Parameters:

dt - Time step in seconds (not used for orifice as it has no accumulation/storage)

id - Unique identifier for this simulation run