com.synerset.hvacengine.fluids.SharedEquations Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of hvac-engine Show documentation

HVAC|Engine is a comprehensive library for calculating moist air properties, including crucial thermodynamic processes such as heating, dry cooling, real cooling with condensate discharge, mixing single or multiple air streams, and more. Immutable, thread-safe, very accurate.

The newest version!

package com.synerset.hvacengine.fluids;

import com.synerset.hvacengine.common.Validators;
import com.synerset.unitility.unitsystem.common.Distance;
import com.synerset.unitility.unitsystem.dimensionless.PrandtlNumber;
import com.synerset.unitility.unitsystem.thermodynamic.*;

public final class SharedEquations {

    private SharedEquations() {
    }

    /**
     * Returns atmospheric pressure based on height above the sea level, Pa
     * REFERENCE SOURCE: [1] [Pat,Pa] (3) [6.2]

     * EQUATION LIMITS: {-5000m,+1100m}

     *
     * @param altitude altitude over sea level (can be negative), m
     * @return atmospheric pressure at provided altitude, Pa
     */
    public static double atmAltitudePressure(double altitude) {
        return 101.325 * Math.pow((1 - 2.25577 * Math.pow(10, -5) * altitude), 5.2559) * 1000;
    }

    public static Pressure atmAltitudePressure(Distance altitude) {
        Validators.requireNotNull(altitude);
        double pressVal = atmAltitudePressure(altitude.getInMeters());
        return Pressure.ofPascal(pressVal);
    }

    /**
     * Returns moist air temperature based on height above the sea level, oC

     * REFERENCE SOURCE: [1] [Pat,Pa] (4) [6.2]

     * EQUATION LIMITS: {-5000m,+1100m}

     *
     * @param tempAtSeaLevel temperature at altitude of 0.0m, oC
     * @param altitude       altitude over sea level (can be negative), m
     * @return temperature at provided altitude, oC
     */
    public static double altitudeTemperature(double tempAtSeaLevel, double altitude) {
        return tempAtSeaLevel - 0.0065 * altitude;
    }

    public static Temperature altitudeTemperature(Temperature tempAtSeaLevel, Distance altitude) {
        Validators.requireNotNull(tempAtSeaLevel);
        Validators.requireNotNull(altitude);
        double tempVal = altitudeTemperature(tempAtSeaLevel.getInCelsius(), altitude.getInMeters());
        return Temperature.ofCelsius(tempVal);
    }

    /**
     * Returns thermal diffusivity, m2/s
     * REFERENCE SOURCE: [8] [am,m2/s] (35) [5]
     *
     * @param rho air density, kg/m3
     * @param k   air thermal conductivity, W/(m*K)
     * @param cp  air specific heat, kJ/kgK
     * @return air thermal diffusivity, m2/s
     */
    public static double thermalDiffusivity(double rho, double k, double cp) {
        return k / (rho * cp * 1000d);
    }

    public static ThermalDiffusivity thermalDiffusivity(Density density, ThermalConductivity thermalConductivity, SpecificHeat specificHeat) {
        Validators.requireNotNull(density);
        Validators.requireNotNull(thermalConductivity);
        Validators.requireNotNull(specificHeat);
        double thermalDiffVal = thermalDiffusivity(density.getInKilogramsPerCubicMeters(),
                thermalConductivity.getInWattsPerMeterKelvin(),
                specificHeat.getInKiloJoulesPerKiloGramKelvin());
        return ThermalDiffusivity.ofSquareMeterPerSecond(thermalDiffVal);
    }

    /**
     * Returns air Prandtl number, -
     * Valid for DA, WV, MA if all arguments are provided for type of fluid.
     *
     * @param dynVis air dynamic viscosity,kg/(m*s)
     * @param k      air thermal conductivity, W/mK
     * @param cp     air specific heat, kJ/kgK
     * @return Prandtl number, -
     */
    public static double prandtlNumber(double dynVis, double k, double cp) {
        return dynVis * cp * 1000d / k;
    }

    public static PrandtlNumber prandtlNumber(DynamicViscosity dynamicViscosity, ThermalConductivity thermalConductivity, SpecificHeat specificHeat) {
        Validators.requireNotNull(dynamicViscosity);
        Validators.requireNotNull(thermalConductivity);
        Validators.requireNotNull(specificHeat);
        double prandtlVal = prandtlNumber(dynamicViscosity.getInPascalsSecond(),
                thermalConductivity.getInWattsPerMeterKelvin(),
                specificHeat.getInKiloJoulesPerKiloGramKelvin());
        return PrandtlNumber.of(prandtlVal);
    }

}