The Numerical Simulation On Fuel Premixed And Prevaporized Process In High-Speed Nozzle

Low pollution combustion will be a tendency for the future advanced gas turbine combustor. The inevitable demand of combustion mode and knowhow technology are LPP(Lean Premixed Prevaporation) technology. Recently, LPP combustion technology has been caused the extensive concerns of domestic and international research workers of research institutions in the experimental application stage.This paper has analysed and CFD numerical simulated the key problem such as the risk of damage to an LPP combustor related to the autoignition and flashback phenomena that may be occured inside the premixing system. Autoignition cann’t occurs if the fuel-air mixture residence time is shorter than fuel ignition delay time. The crossflow of fuel jet in the air flow is a efficient method for LPP, currently however, it was mainly investigated by experimental method. The premixed process and law for the crossflow of fuel jet in airflow in the limited space were CFD numerical studied. On this basis, combining with others experimental research, designed a rapid and efficient LPP model nozzle. The prediction of performance was analysed, its pre-mixing combustion effects were evaluated in the model combustion chamber, and these make the research results with engineering application value.Based on experimental study, the jet crossflow mix process of single hole fuel jet with high speed airflow was simulated in the CFD software with the Euler-Euler two-phase flow model combined with UDF method. The results according with the testing conclusion were obtained. By studying the laws of jet flow mechanics and jet penetration depth, the primary factors that influence on penetration depth and jet bending along the airflow direction with the formation of the kidney vortex were acquired. Series analysis were carried through about the spray forming mechanism and its main influence factors on the atomization that interior kidney vortex gradually strengthened until the surface fracture and breakup to droplets. On this basis, this paper introduces the design of different internal structure of rapid mixing nozzle, and the performance such as evaporation time, mass and heat transfer, and total pressure loss were numerical simulated. Finally, in order to validate the combustion performance of the rapid mixing nozzle, according to others’combustion chamber test, the multi-point direct jet LPP combustion chamber was designed. By using the multi-step reaction mechanism of flammable gas mixture, the combustion characteristics of rapid mixing nozzle were numerical analyzed. It is conclusion that LPP combustion has the performances of high efficiency and low NOx emissions.