Week 10 - Simulating Combustion of Natural Gas.

Aim

To perform a simulation for combustion of natural gas.

Introduction

Natural gas is an extremely important source of energy for reducing pollution and maintaining a clean and healthy environment. In addition to being domestically abundant and secure source of energy,the use of natural gas also offers a number of environmental benefits over other sources of energy,particulary other fossil fuels.

The combustion is defined as a chemical reaction in which a hyderocarbon fuel reacts with an oxidant to form produts,accompanied with release of energy in the form of heat. Being the integral part of various engineering application like internal combustion engines , furnace , power station combustors , combustion exhibits itself as a wide domain during the design,analysis and performance characteristics stages of then above mentioned applications.

In this simulation the nox and soot is getting formed at the outlet of the combustor, such formstion has harmful effects on the environment and human beings.The stringent government norms also demand the least formation of nox and soot and to satisfy those requirements , we need to check the effect of adding water in the fuel.

Here We add the water content in the fuel from 5% to 30% by mole and observe the effect of it on the results.

Objectives & results

Performing a combustion simulation on the combustor model and plotting the variation of the mass fraction of the different species’ in the simulation using line probes at different locations of the combustor.

Geometry

Part-2

1. 5% water

2. 10% water

3. 15% water

4. 20% water

5. 25% water

6. 30% water

Conclusions

In this project the mass fraction of products from NOx and soot emmisions are predicted using ansys fluent.

• The temperature drops as we add water from 5% to 30%.
• Diluting the fuel with water reduces the effect of harmful pollutants such as NOx and soot at the outlet.
• The rate of reduction in concentration is greater than that of NOx when diluting fuel with water.
• Since soot value decreases with dilution we can say that there is less wastage of fuel.
• Fuel dilution by water is a great way to reduce emmisions.
• After checking the mass fraction of soot formation it is evident that for all cases the result is unbalanced.But the amount of soot formation is signifacantly lower.
• Eddy-dissipation model helps us model combustion process via turbulence mixing without the presence of an ignition source.