Simulation Study On Low Emission Combustion Technology Of Dual Fuel Combustor In Gas Turbine

At present,China's environmental crisis,low efficiency utilization of energy,unreasonable disadvantages are becoming increasingly serious,as a kind of significant equipment for the country,gas turbine has become the focus of research at the present stage in china.Low emission combustion technology,as the core technology of combustor,is an important index to measure the performance of gas turbine,and has become the focus of market competition for gas turbine products.The dual fuel combustion technology is a front direction of low emission combustion chamber,based on the existing marine of liquid fuel gas turbine,through theoretical analysis,structure design and numerical simulation,this paper fully carry out the dual fuel gas turbine performance investigation to meet the requirements of low emission.According to the three kinds of NOx generating mechanism in the dual fuel combustion chamber,the key factors of NOx genetrating are analyzed and the results show that NOx formation mainly depends on the combustor primary zone of equivalence ratio,and the mixture of the fuel and air uniformity.In addition,NOx emission prediction methods based on different main factors and NOx emission control methods with different working principles have been established,and a NOx emission prediction method suitable for lean burn premixed combustion mode combined with steam injection technology has been determined.The design method of low emission dual fuel combustor is studied.The principle of air flow distribution in the combustion chamber and the principle of the intake distribution of the dual fuel nozzle are established.Based on the above principles,the results of the air and fuel distribution in the combustor are given,and the structural design results of the combustion chamber and swirler nozzle are alsopresented,and the performance of the retrofit dual fuel combustor is predicted.The results show that the performance of the dual fuel combustor meets the design requirements.A three-dimensional numerical simulation geometric model of dual fuel combustor is established.The influence of swirl,nozzle moment,depth of cracking and steam injection on the performance of dual fuel combustor is analyzed.The results show that the spin down in the cyclone left 45 degrees,compared to the left 30 degrees of rotation,the combustion flame structure is more reasonable,the outlet temperature quality meet the design requirements;Under the 4 different kinds of nozzle distances,the best position design of the dual fuel combustion chamber nozzle is 38.764 mm,in this position of the combustion nozzle,fuel can fully premix,which is conducive to further research on improving combustion performance;with the increase of fuel cracking depth,the combustion flame moving from the initial tissue mainly distributed in the main combustion zone to the outlet of the combustion chamber,there is a decrease of the uniformity of the outlet temperature field,under 60% and 80% cracking depth,the wall temperature distribution are similar with little difference,while under the 100% cracking depth,the wall temperature of main combustion zone decrease significantly due to the moving rearward of the flame;with the increase of steam injection volume,the effect of steam injection on the combustion flame gradually increased,we can see that from 10% to 50% the high temperature zone is mainly concentrated in the head area of flame tube,with the increase of the amount of steam injection,influence of steam volume on combustion field is increasing,flame moves rearward obviously,under the 250% conditions,reaction occurs near the mixing hole,therefore near the exit area of the outlet temperature uniformity increased significantly.This paper presents a simulation method of dual fuel gas turbine combustion chamber with low emission combustion technology,and the design of dual fuel combustion chamber was numerically simulated by using CFD software,which has an important significance for the transformation of gas turbine combustor chamber and the application of CFD in dual fuel gas turbine combustor.