Design And Performance Study Of Marine Low Emission Tower Type Coaxials Taged Combustor

With the development and wide application of gas turbine,reducing the pollutant emission at the outlet of combustion chamber has gradually attracted people’s attention.The development direction of combustion chamber R & D and design is to realize low emission combustion while ensuring combustion performance.The key to the flow field structure and combustion organization of low emission combustion chamber lies in the design of head hydrocyclone.Different hydrocyclone structures have different ways of air organization,and the flow field structure has a great impact on the combustion of fuel.In this paper,lean premixed combustion technology is adopted,and the structure design of the head hydrocyclone and the overall scheme design of the combustion chamber are studied based on the prototype combustion chamber.A multi swirl Low Emission Tower type Coaxials taged Combustor(LETCC)scheme is proposed,and the performance of the combustion chamber is studied by means of numerical simulation.The main research contents of this paper are as follows:(1)Through the assistance of empirical formula and numerical simulation,the structure of multi swirl tower staged hydrocyclone is designed.According to the design principle of low emission combustion chamber,the modification design is carried out on the basis of the flame tube of the prototype combustion chamber,and the tower staged lean oil premixed low emission combustion chamber is obtained.(2)The combustion performance of prototype combustor and tower staged combustor is compared by numerical simulation,and the differences and reasons of temperature field,velocity field and high temperature zone between the two combustors are analyzed.The results show that under the design condition,the outlet NOx emission of low emission combustion chamber is 45.39 ppm,CO emission is 34.3ppm,OTDF is 27.39%,RTDF is 16%.The tower staged combustion chamber with lean premixed combustion technology has good combustion performance and emission performance.(3)Under the design condition,the effects of the combination mode of rotation direction,the swirl number of the main combustion stage,the inclined radial angle of the tower hydrocyclone and the axial position of the primary fuel injection on the combustion performance were investigated.The results show that the combustion chamber has better comprehensive performance parameters when the four-stage hydrocyclone is in the same rotation direction,the number of primary swirl of main combustion is 0.65,the number of secondary swirl of main combustion is 0.9,the inclined radial angle of tower hydrocyclone is45 °,and the axial position of primary fuel injection of main combustion is 20 mm.When the main combustion stage rotates in the same direction,the average temperature of the combustion chamber is low;With the increase of secondary swirl number of main combustion,the axial size of main recirculation zone gradually decreases and the radial size gradually increases;With the increase of oblique radial direction,the central axis temperature of combustion chamber decreases gradually.(4)The off design performance of tower staged low emission combustor was studied.Under high operating conditions,the effects of Fuel Classification ratio of main combustion stage on combustion performance and emission performance were studied.The results show that under the condition of 1.0,the NOx emission at the outlet decreases gradually with the increase of the classification proportion of the main combustion stage fuel.When the classification proportion of the main combustion stage fuel is 1.4,the minimum NOx emission at the outlet of the combustion chamber is 37.15ppm;Under the working condition of 0.8,the change of Fuel Classification proportion has little effect on the outlet NOx emission.When the main fuel classification proportion is 1.1,the NOx emission is lower,which is 13.83 ppm.When the fuel classification ratio of the main combustion stage is near1.1,the combustion efficiency under 1.0 and 0.8 conditions is the highest,which are 99.661%and 99.653% respectively.