| The pressure-swirl nozzle is widely used because of its simple structure,stable atomization performance and reliable operation.The application covers industrial fields,transportation,agricultural production fields,and people's daily life.The study of this paper is about the pressure-swirl nozzle in the gas turbine combustors.Through the numerical simulation,we study spray characteristics of the nozzle and the flow conditions of different kinds of fuel in the internal and external flow field of the nozzle under different inlet conditions and different nozzle structures,and to discuss the atomization characteristics of the pressure-swirl nozzle.The atomization effect of the centrifugal nozzle directly affects the stability and work efficiency of the combustion chamber in the gas turbine.Therefore,in the numerical simulation study of this paper,the centrifugal nozzle model is mainly meshed by Gambit software,the three-dimensional numerical simulation of the centrifugal nozzle by the Fluent software,the gas-liquid interface is tracked by the VOF method,and the Realizable k-? turbulence model is simulated the entire flow process.The number of tangential inlets,the angle of inclination of the inlet,and the atomization characteristics of different fuel types under different inlet parameters were studied.When the number of tangential inlets is 1,2,3,and 4,respectively,the variation of the atomization characteristics of four pressure-swirl nozzles is studied,including the swirl intensity of the internal flow field of the nozzle,the velocity distribution of the fuel at the outlet of the nozzle,and the pressure distribution.The gas-liquid two-phase distribution,as well as the atomization cone angle at the outlet of the nozzle,showed that the change in the number of tangential inlets hardly affected the atomization characteristics of the nozzle.Change the type of fuel and choose kerosene,kerosene 80% + ethanol 20%(volume ratio),kerosene 70% + ethanol 30%(volume ratio),respectively,to discuss the nozzle atomization characteristics of the change,the results shows that with the increase of the volume fraction of ethanol in the mixed fuel,the velocity at the outlet of the nozzle increases.The angle of inclination of the nozzle inlet was changed,and four kinds of pressure-swirl nozzles with inclination angles of 0°,15°,30°,and 45° were selected for numerical simulation.The regularity of atomization characteristics was obtained: as the angle of inclination increased,the velocity of the fuel at the outlet of the nozzle and the atomization cone angle both increase first and then decrease,and there is an optimum angle to optimize the atomization effect of the nozzle.The number of three inlet nozzles with an inlet tilt angle of 0° was selected as the numerical simulation object.The inlet pressure conditions were changed to study the atomization characteristics of the nozzle under different inlet pressure conditions.The experimental research related to the numerical simulation study was conducted,and the simulation results were compared with the experimental results.The results showed that although there was an error between the two,the overall change rule was the same.The experimental results can verify the correctness of the numerical simulation model and get the conclusion of the atomization characteristics of the corresponding centrifugal nozzle. |
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