Numerical Study on Spray Characteristics of Jet Breakup Using a Phase-Field-Based Lattice Boltzmann Model

Liquid fuel breakup is a critical process in the field of energy and power engineering, and understanding its mechanisms is significant to enhancing the fuel atomization efficiency. In this paper, the fuel jet breakup process and its spray characteristics are investigated numerically by using a phase-field-based lattice Boltzmann model. The spray characteristics are analyzed quantitatively from three aspects, including the spray penetration, the atomized droplet distributions, and the atomization cone angle, and a coefficient of atomization dispersion angle is proposed to describe the atomization angle and spatial dispersion of the atomized droplets. The numerical results show that the spray penetration is proportional to time before the first breakup, then it turns into the 0.6 power of time. The changes in the number of droplets, the average droplet equivalent diameter, and the droplet velocity in the jet direction as functions of time occur in accordance with the Boltzmann distribution, the logistic distribution, and the exponential associated distribution, respectively, and the bimodality is the most obvious characteristic in the probability distribution of the droplet velocity. The atomization dispersion angle tends to be steady as the fuel jet is fully developed, which is more suitable for characterizing the jet breakup process as compared to the maximum atomization angle.