NeqSim’s Pump models a liquid pump from a process inlet stream. Use either a specified discharge pressure and isentropic efficiency, a vendor head/efficiency curve, or a specified discharge temperature. PumpMechanicalDesign adds preliminary mechanical-design calculations and an auditable API 610 screening result.

Packages

Class Package Purpose
Pump neqsim.process.equipment.pump Steady-state and transient process calculation
PumpChartInterface neqsim.process.equipment.pump Vendor head, efficiency, and NPSHr curves
PumpMechanicalDesign neqsim.process.mechanicaldesign.pump Preliminary sizing and design outputs
PumpApi610DesignCalculator neqsim.process.mechanicaldesign.pump Structured API 610 screening checks

Calculation modes

Specified discharge pressure

Set the discharge pressure and isentropic efficiency before calling run():

pump.setOutletPressure(15.0, "bara");
pump.setIsentropicEfficiency(0.78);
pump.run();

The absorbed shaft power is based on the isentropic enthalpy rise divided by the specified efficiency:

\[P = \frac{\dot m\left(h_{2s}-h_1\right)}{\eta_s}\]

Here $P$ is shaft power, $\dot m$ is mass flow, $h_1$ is inlet specific enthalpy, $h_{2s}$ is the isentropic discharge enthalpy, and $\eta_s$ is isentropic efficiency.

Vendor performance curves

Supply one row per speed to PumpChartInterface.setCurves(...). Flow is in m³/h, efficiency is supplied in percent, and the head unit is set separately. The NPSHr array must have the same speed/flow layout.

double[] speed = new double[] { 1000.0 };
double[][] flow = new double[][] { { 50.0, 75.0, 100.0, 125.0, 150.0 } };
double[][] head = new double[][] { { 120.0, 115.0, 105.0, 90.0, 70.0 } };
double[][] efficiency = new double[][] { { 65.0, 75.0, 82.0, 78.0, 68.0 } };
double[][] npshRequired = new double[][] { { 2.0, 2.4, 3.0, 4.0, 5.5 } };

pump.getPumpChart().setCurves(new double[] {}, speed, flow, head, efficiency);
pump.getPumpChart().setHeadUnit("meter");
pump.getPumpChart().setNPSHCurve(npshRequired);
pump.setSpeed(1000.0);
pump.run();

Do not use setHeadCurve, setEfficiencyCurve, or setNPSHRequiredCurve; those convenience methods are not part of the current Pump API.

Specified discharge temperature

Calling setOutletTemperature(...) selects the fixed-temperature mode. NeqSim performs a TP flash at the specified discharge temperature and pressure and back-calculates power from the inlet/outlet enthalpy difference. This mode represents a measured or externally specified discharge state; it does not evaluate a vendor performance curve.

pump.setOutletPressure(15.0, "bara");
pump.setOutletTemperature(35.0, "C");
pump.run();

setOutTemperature(double) is deprecated. Use setOutletTemperature(double) for kelvin or setOutletTemperature(double, String) for an explicit unit.

NPSH screening

getNPSHAvailable() returns metres of liquid head. It clones the inlet fluid, calculates its bubble-point pressure at the inlet temperature, and evaluates the pressure head. The current implementation assumes zero velocity-head contribution and expects static elevation effects to already be represented in the suction system:

\[NPSH_A = \frac{P_s-P_v}{\rho g}\]

where $P_s$ is absolute suction pressure, $P_v$ is bubble-point pressure, $\rho$ is inlet-fluid density, and $g$ is gravitational acceleration. A failed bubble-point calculation returns Double.NaN; it is not interpreted as a large safe margin.

getNPSHRequired() returns the interpolated vendor NPSHr when a chart is present. Without a vendor NPSHr curve it returns a coarse flow-based screening estimate. Treat that fallback as a data gap, not as vendor qualification.

double npshAvailableM = pump.getNPSHAvailable();
double npshRequiredM = pump.getNPSHRequired();
pump.setCheckNPSH(true);
pump.setNPSHMargin(1.15);
boolean cavitationRisk = pump.isCavitating();

The getter methods do not accept unit strings; both values are returned in metres.

API 610 mechanical-design screening

PumpMechanicalDesign combines the simulated duty with purchaser inputs and vendor curve data. Its PumpApi610DesignCalculator reports each check as PASS, WARNING, FAIL, or NOT_EVALUATED, and combines them into PASS, PASS_WITH_WARNINGS, FAIL, or NOT_EVALUATED.

The screen covers:

Missing purchaser or vendor values remain NOT_EVALUATED. NeqSim does not certify casing, rotor, bearing, nozzle, seal, baseplate, material, inspection, or test compliance. Use the purchased standard edition, project specification, and vendor documentation for final design.

Complete Java example

This Java 8 example runs a single-phase liquid pump with a vendor curve, checks NPSH, performs the API 610 screen, and exports the structured mechanical-design response. The inlet uses n-hexane so the actual-volume flow conversion is based on one stable liquid phase at the stated temperature and pressure.

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import neqsim.process.equipment.pump.Pump;
import neqsim.process.equipment.stream.Stream;
import neqsim.process.mechanicaldesign.pump.PumpApi610DesignCalculator;
import neqsim.process.mechanicaldesign.pump.PumpMechanicalDesign;
import neqsim.thermo.system.SystemInterface;
import neqsim.thermo.system.SystemSrkEos;

public final class PumpDesignExample {
  private static final Logger logger = LogManager.getLogger(PumpDesignExample.class);

  private PumpDesignExample() {}

  public static void main(String[] args) {
    SystemInterface fluid = new SystemSrkEos(298.15, 5.0);
    fluid.addComponent("n-hexane", 1.0);
    fluid.setMixingRule("classic");

    Stream feed = new Stream("pump feed", fluid);
    feed.setFlowRate(100.0, "m3/hr");
    feed.run();

    Pump pump = new Pump("P-100", feed);
    double[] speed = new double[] { 1000.0 };
    double[][] flow = new double[][] { { 50.0, 75.0, 100.0, 125.0, 150.0 } };
    double[][] head = new double[][] { { 120.0, 115.0, 105.0, 90.0, 70.0 } };
    double[][] efficiency = new double[][] { { 65.0, 75.0, 82.0, 78.0, 68.0 } };
    double[][] npshRequired = new double[][] { { 2.0, 2.4, 3.0, 4.0, 5.5 } };

    pump.getPumpChart().setCurves(new double[] {}, speed, flow, head, efficiency);
    pump.getPumpChart().setHeadUnit("meter");
    pump.getPumpChart().setNPSHCurve(npshRequired);
    pump.setSpeed(1000.0);
    pump.setCheckNPSH(true);
    pump.setNPSHMargin(1.15);
    pump.run();

    double powerKw = pump.getPower("kW");
    double vendorHeadM = pump.getPumpChart().getHead(feed.getFlowRate("m3/hr"), pump.getSpeed());
    double npshAvailableM = pump.getNPSHAvailable();
    double npshRequiredM = pump.getNPSHRequired();

    PumpMechanicalDesign design = pump.getMechanicalDesign();
    design.setApi610PumpType(PumpApi610DesignCalculator.Api610PumpType.OH2);
    design.setMaximumSuctionPressure(8.0);
    design.setFurnishedCasingMawp(25.0);
    design.calcDesign();

    PumpApi610DesignCalculator assessment = design.getApi610Assessment();
    PumpApi610DesignCalculator.AssessmentStatus status = assessment.getAssessmentStatus();
    String responseJson = design.getResponse().toJson();

    logger.info("Power: {} kW; vendor head: {} m", powerKw, vendorHeadM);
    logger.info("NPSHa: {} m; NPSHr: {} m", npshAvailableM, npshRequiredM);
    logger.info("API 610 status: {}; response: {}", status, responseJson);
  }
}

Interpreting results

Result Interpretation
pump.getPower("kW") Absorbed shaft power calculated by the process model
pump.getPumpChart().getHead(flow, speed) Vendor-curve head in the configured head unit
pump.getNPSHAvailable() Process-side NPSHa in metres, or NaN if unavailable
pump.getNPSHRequired() Fitted vendor-curve value or coarse fallback estimate in metres
assessment.getOperatingRegion() Rated-point classification relative to vendor BEP
assessment.getSelectedDriverPowerKw() First configured rating meeting the required driver power
assessment.getRequiredCasingPressureBara() Screening casing-pressure requirement in bara
assessment.getChecks() Immutable list of individual checks and missing-evidence findings

Limitations