Linear stability analysis of a slightly viscoelastic liquid jet

Gel propellant is one of the non-Newtonian viscoelastic liquids. The study of breakup of a gel propellant jet emanating from an injector has always been a fundamental task for a propulsion system with gel propellants. In this paper, a linear instability analysis method has been used to investigate the breakup of a slightly viscoelastic liquid jet. The disturbance wave growth rate of the axisymmetric mode has been determined by solving the dispersion equation of a slightly viscoelastic liquid jet, which was obtained by combining the linear instability theory and the linear viscoelastic model. Moreover, the maximum growth rate and corresponding dominant wave number have been observed, according to which maximum growth rate curves and dominant wave number curves have been plotted; this theory has been verified in the experiments of other authors. The time constant ratio, zero shear viscosity, liquid jet velocity, surface tension, liquid jet radius, liquid density and the gas density have been tested for their influence on the instability of the viscoelastic liquid jet. The results show that the effect of gas density is the greatest on the breakup of the viscoelastic jet, the jet velocity is affected second and the zero shear viscosity is least affected. However, the effects of other parameters are limited.