Research On The Atomization Characteristics Of Liquid Fuel Injection In A Continuously Rotating Detonation Engine

Continuous rotating detonation engine(CRDE)is a new concept engine that uses detonation waves to continuously propagate in one end of the annular combustion chamber,and the detonation products are discharged at high speed from the other end to generate thrust.It has the advantages of large specific impulse,high working frequency and compact structure,and is one of the most potential new aerospace power plants.With the deepening of engineering research,CRDE using liquid fuel has become a hot spot,in which the atomization of liquid fuel is a key factor for the initiation of the engine and the steady propagation of rotating detonation wave.In this paper,numerical simulations and experimental researches are both used to investigate the atomization characteristics of liquid fuel injection in the annular combustion chamber of CRDE.The main work is as follows:(1)The spray Foam solver based on the Euler-Lagrange method in open source software Open FOAM was used to simulate the liquid fuel atomization in the annular combustion chamber of CRDE.(2)Numerical simulations of the atomization process of the liquid fuel in the annular combustion chamber under different injection structures were carried out.The results show that in the gas-liquid coaxial atomization,when the angle between adjacent nozzles is 15°,the droplet size is the smallest and the distribution is relatively uniform.In the gas-liquid crossflow atomization,the increase of the incoming flow velocity and the kerosene jet velocity leads to the increase of the deflection degree of the jet and the decrease of the droplet size.In the gasliquid impinging atomization,the jet penetration distance is greatly affected by the incoming flow velocity.While increasing the injection angle will reduce the droplet size and mass distribution.(3)Numerical simulations of the atomization process under different break-up models were performed.Under the same working conditions,the kerosene spray atomization characteristics under different break-up models are obtained,and the comparison shows that Reitz Diwakar secondary break-up model is the most suitable one without considering the primary break-up process.(4)Three fuel injection structures were designed,and experimental researches were carried out on the kerosene jet atomization process with those different injection structures.The results show that in the experiment of gas-liquid coaxial atomization,When the nitrogen pressure is 0.6MPa,the droplet size is the smallest,which is 11.2?m.In the gas-liquid crossflow atomization experiment,the droplet size decreases with the increase of kerosene pressure,and the degree of jet deflection decreases.In the gas-liquid impinging atomization experiment.When the kerosene mass flow rate is 9.2g/s,the droplet size is the smallest and the droplet distribution is relatively uniform.(5)Through numerical simulations and experimental researches,the atomization process of the liquid fuel under the three injection structures was compared.The results show that the gas-liquid impinging atomization is the most reasonable arrangement in the annular combustion chamber considering both the overall average droplet diameter and the jet penetration distance.In this paper,the method of numerical simulations and experimental researches reveals the atomization law of liquid fuel in the annular combustion chamber,which is of great significance to promote the initiation and stable propagation of liquid fuel CRDE.