Study On Premixing Performance Of Fuel In Combustion Chamber

With the wide application of gas turbine,the restrictions on pollution emission of gas turbine are becoming more and more stringent all over the world.How to achieve better gas turbine performance and lower pollutant emission level at the same time has become the focus of current research.Nitrogen oxide(NOx)is one of the main exhaust pollutants of gas turbine.The uniformity of fuel / air mixing is one of the main factors affecting the production of NOx in gas turbine combustion chamber.Uneven mixing means that there are different fuel component distributions at each point in the combustion chamber,which also has different equivalent ratio distribution.This kind of non-uniformity mixing combustion mode will make the temperature field produce uneven distribution,produce local hot spots,and cause the emission performance to deteriorate.Therefore,it is very important to study the mixing performance of fuel/air.In this paper,numerical simulation methods are used to study the mixing rules of methane and air in rectangular channels and swirl channels.Based on the obtained rules,comprehensive analysis is performed on the parameters of the mixing holes at various levels of the premixing stage.Finally,the methane / air mixing of the whole premixed stage is analyzed.The main work of this article is:(1)The numerical simulation method was used to study the effects of factors such as the number of holes,pore diameter,pore angle,pore position and mixing distance on the mixing performance of methane / air in a rectangular channel.The mixing mechanism of methane and air is analyzed,and the mixing law of methane and air in rectangular channel is obtained.The mixing law of methane / air in the channel;it was found that the mixing performance of methane / air was mainly related to the jet depth.(2)Under the condition of the same Reynolds number at the inlet,the effects of factors such as the number of holes,pore diameter,pore angle,pore position,and mixing distance on the methane / air mixing performance in the swirl channel were studied using numerical simulation methods.Mixing rules of methane / air in the flow channel;The mixing conditions of methane / air in the swirling channel under different pore arrangements are discussed,and several pore arrangements with better mixing conditions are obtained;according to the rules obtained previously The mixing hole scheme of the swirling channel was discussed,and the non-uniformity of the swirling channel with better mixing performance was finally 4.64%.(3)Under the condition of the same inlet Reynolds number,discuss the effect of the equivalent diameter on the methane / air mixing performance in the rectangular channel,single-hole swirl channel,and four-hole swirl channel.The mixing performance of methane /air in the channel does not change much;the mixing conditions of methane / air in the channel under variable flow conditions are discussed,and it is found that the inlet flow has basically no effect on the mixing performance;according to the structural characteristics of the combustion chamber,combining the rectangular and The mixing characteristics of methane /air in the swirl channel and its key influencing factors.The structural parameters of the mixing pores at various levels of the premixing stage were comprehensively analyzed to obtain the mixing pore schemes at each level.The uniformity is 5.32%.