The Research For Plasma Ignition Characteristics Of Lean Combustion

With the continuous development of modern industry, the amount of low calorific value fuel such as coal mine methane gas and industrial emissions are more and more. In the past, this low calorific value waste gas is emptying directly without any treatment. Doing like this not only causes a serious waste of energy but also exacerbate the greenhouse effect. In response to this situation, people think of the lean-burn technology, which developed from the seventies of the last century and get more and more attention because of growing energy crisis today. The lean burn technology makes the combustion of low calorific value fuel become a reality.Firstly, this paper introduce the High Temperature Air Combustion Technology, the Porous Combustor Technology, the Swiss-roll Combustor Technology and the Catalytic Combustion Technology.They are widely-used new type lean combustion technologies which base the theory of excess enthalpy combustion. The ignition of low concentration fuel is more difficult so that people think of using thermal plasma to ignite the fuel.This paper introduce the structure of plasma ignition system detailedly.Secondly, the effects of adding oxygen atoms on lean fuel oxidation process is simulated by the chemical kinetics software CHEMKIN with detailed reaction kinetics GRI3.0. Study shows that the oxygen atom plays a very important role in fuel oxidation. It can increase the oxidation speed, shorten the Ignition delay period, improve the fuel conversion rate and make flame temperature higher at last.In order to study the role of plasma in lean combustion accurately and take into account savings computing time, the most important purpose is providing an effective way for the coupling of the chemical reaction kinetics model and FLUENT multidimensional model, this paper use the principal component analysis, based on the special condition, to simplify the GRI3.0detailed mechanism to one simplified model including37components,55elementary reactions.After that, the simplified model is compared with GRI3.0detailed mechanism and the results show the simplified one is correct and available.Thirdly, taking the CHEMKIN and FLUENT as a research platform, this paper establish a model which couples detailed chemical reaction kinetics and two-dimensional CFD to simulate the low concertration methane combustion process accurately. The key parameters of the plasma ignition characteristics can be obtained by this simulation, such as temperature field, the active component field and the fuel and combustion products fields. The ignition characteristics of plasma ignition burner can be studied by analyzing these date.Finally, the ignition and combustion process of plasma ignition combustor is simulated in different conditions.The effects of fuel velocity, methane concentration and fuel original temperature are gained, which supply gist with ameliorating and designing plasma combustor which is used in lean combustion field...