modelFullConversion_idealGas

Full conversion, fuel type independent combustion model for emission calculation purpose
Diagram of FullConversion_idealGas

Extends from TransiEnt.Basics.Icons.FullConversion, TransiEnt.Components.Gas.Combustion.Basics.CombustionBaseClass_idealGas (base class for combustion models).

Information

1. Purpose of model

Simple and effective (no TILMedia-Objects) model for an ideal chemical combustion of natural gas to calculate the exhaust mass flow and gas composition for the default gastype gasModel2 as defined in the simCenter repository at a given lambda.

2. Level of detail, physical effects considered, and physical insight

Full conversion of all combustibles. Air inflow calculated internally for (super)stoichiometric combustion (lambda).

3. Limits of validity

Generation of CO, NOx, SO2 is neglected.

Air and flue gasTypes are final.

4. Interfaces

gasPortIn/Out - port for fuelgas at the inlet and exhaustgas at the outlet

5. Nomenclature

(no elements)

6. Governing Equations

The exhaust gas composition is calculated by a simple set of balance equations for the chemical elements in the molecules of fuelgas and air.

The flow of the fuel gas components is tranlsated into a flow of chemical elements by the external function Comps2ElementsGas, wherein combustible (not fully oxidized) and non-combustible (from CO2, H2O) C and H are fully considered.

The air gasType is fixed with the components:

  1. Water
  2. Nitrogen
  3. Oxygen

Required oxigen/air for stoichiometric combustion are then read out by the external function OxygenDemand and calculated:

mair,req = nO2,req · MO2 / ξO2,air

and

mair = mair,req · λ

With the air composition and inflow the component outflow of the flue gas is calculated. It is assumed to be composed of (in the shown order)

  1. Water
  2. Carbon dioxide
  3. Carbon monoxide
  4. Hydrogen
  5. Oxygen
  6. Nitric oxide
  7. Nitric dioxide
  8. Sulfur dioxide
  9. Nitrogen

This yields with CO, NOx, SOx neglected:

nH2O,flue = 0.5nH,fuel + nH2O,air

nCO2,flue = nC,fuel

nO2,flue = nO2,air - nO2,req

nN2,flue = nN2,fuel + nN2,air

The mass flow rate is calculated by a simple mass balance equation, which yields

mfuel,in + mair,in + mflue,out = 0, where mair,in is calculated internally.

7. Remarks for Usage

(no elements)

8. Validation

Tested in check model "TransiEnt.Components.Gas.Combustion.Check.TestCombustion"

9. References

(no remarks)

10. Version History

Created by Jan Braune (jan.braune@tuhh.de), Mar 2015

Edited by Paul Kernstock (paul.kernstock@tuhh.de), Aug 2015

Edited by Lisa Andresen (andresen@tuhh.de), Dec 2015

Parameters

TypeNameDefaultDescription
TILMedia.GasTypes.BaseGasFuelMedium (from CombustionBaseClass_idealGas)simCenter.gasModel2Fuel medium
TransiEnt.Basics.Media.Gases.Gas_ExhaustGasExhaustGas (from CombustionBaseClass_idealGas)Exhaust gas medium type
SI.MolarMass[airType.nc_propertyCalculation]M_i_airTransiEnt.Basics.Functions.GasProperties.getMolarMasses_idealGas(airType, airType.nc_propertyCalculation)[O2, N2] Air molar masses
SI.MolarMass[FuelMedium.nc_propertyCalculation]M_i_fuelTransiEnt.Basics.Functions.GasProperties.getMolarMasses_idealGas(FuelMedium, FuelMedium.nc_propertyCalculation)Fuel molar masses
SI.MolarMass[ExhaustGas.nc_propertyCalculation]M_i_exhTransiEnt.Basics.Functions.GasProperties.getMolarMasses_idealGas(ExhaustGas, ExhaustGas.nc_propertyCalculation)[H2O, CO2, CO, H2, O2, NO, NO2, SO2, N2] Exhaust molar masses
TransiEnt.Basics.Records.GasProperties.OxygenDemandCombustionoxygenDemand
TransiEnt.Basics.Media.Gases.Gas_MoistAirairTypeAir medium type
SI.MassFractionxi_airairType.xi_default[H2O, N2, O2] Air components mass fraction
Reallambda1.2Air ratio

Connectors

TypeNameDefaultDescription
TransiEnt.Basics.Interfaces.Gas.IdealGasEnthPortOutgasPortOut (from CombustionBaseClass_idealGas)
TransiEnt.Basics.Interfaces.Gas.IdealGasEnthPortIngasPortIn (from CombustionBaseClass_idealGas)

Components

TypeNameDefaultDescription
TransiEnt.SimCentersimCenter (from CombustionBaseClass_idealGas)
Modelica.Units.SI.MassFlowRatem_flow_air