.TransiEnt.Components.Gas.Combustion.FullConversion_idealGas

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, NO_x, 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:

m_air,req = n_O2,req · M_O2 / ξ_O2,air

and

m_air = m_air,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, NO_x, SO_x neglected:

n_H2O,flue = 0.5n_H,fuel + n_H2O,air

n_CO2,flue = n_C,fuel

n_O2,flue = n_O2,air - n_O2,req

n_N2,flue = n_N2,fuel + n_N2,air

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

m_fuel,in + m_air,in + m_flue,out = 0, where m_air,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