Study On Rheology And Injection Dynamics Of Gelled Kerosene

Gelled kerosene is formed by adding gelling agent,and has stable structural.Compared with kerosene,gelled kerosene is hard to leak and volatilize,and can further increase the strength of energy density by adding energy-containing particles.So,it has high application prospect in aerospace field.But the complex rheology and injection dynamics of gelled kerosene affect the atomization effect of propellant Furthermore,the efficiency and stable combustion of propellant and the performance of the engine are affected.Therefore,the study of the preparation,rheologyand injection dynamics of gelled kerosene are carried out,and have important significance of engineering and science to promote the application of gelled kerosene.A variety of gelled kerosene were prepared and their rheology were measured,the internal flow of the injector is simulated numerically,a single-stock jet experimental platform for gel was set up,and the disturbance of the jet flow was conducted by a linear analysis.The main research works of this paper include:(1)The inorganic and organic gelled kerosene was prepared by gellants and experimental equipment.The yield stress,thixotropy,viscosity and stability were measured and were characterized by the rheological parameters.The results show:gelled kerosene can be formed by adding fumed silica and some organic gallants.Inorganic and organic gallants have different gelatinization mechanism,and heating can improve the quality of organic gelled kerosene;The prepared gelled kerosene both have yield stress,their yield stress increases with the increase of gellant content,and the yield stress of organic gelled kerosene is less than that of inorganic;The stability of gelled kerosene increases with the increase of gellant content,and decrease with the increase of centrifugal force,and the stability of organic gelled kerosene is better than that of inorganic;Gelled kerosene has the thixotropic property of large decrease on viscosity in short time;The viscosity of gelled kerosene increase with the increase of gellant content,The value of n decreases with the increase of gellant content,and the consistency coefficient K does not show definite rule.(2)By SOLA algorithm of staggered grids,the numerical calculation of the rheological properties of gelled kerosene in the conical injector was carried out,and the influence of the length diameter ratio and the convergence Angle on the pressure loss,velocity field and viscosity field of the injector was analyzed.The results show:The theoretical solution is consistent with the numerical solution,and the validity and applicability of the numerical method are verified;The conical injector is beneficial to the shear thinning properties of gelled kerosene;The section of the outlet has no influence on the flow field in the nozzle,However,the average apparent viscosity of the outlet of the injector was increased;The convergence angle significantly affects the velocity distribution in the injector,but it has little effect on the velocity distribution of the export section;The relative decrease range of apparent viscosity decreases with the increase of convergence angle,and the pressure loss increases as the increases of convergence angle.(3)A single-stock jet experimental platform for gelled kerosene was set up,the morphology and perturbation characteristics of the jet flow were captured by high-speed photography,the disturbance characteristics of the jet flow were analyzed by linear stability method,The amplitude of disturbance on different jet flow length was calculated,and compared with the experiment The results show:,The disturbance of the gel simulated liquid increases gradually with the increase of the jet flow velocity;When the average velocity of the injection exceeds 30.84m/s,The jet flow surface bursts,and the higher the average velocity of the jet flow,the earlier the jet flow burst and the higher the crushing degree;In view of the limitations of the Yang linear analysis method in the high dilution gel,an improved method is proposed the linear,and shows good adaptability,because perturbation equation of jet flow is solved by introducing the interface velocity factor.