On Shear Rheology of Gel Propellants

Abstract

Selected fuel, oxidizer and simulant gels were prepared and rheologically characterized using a rotational rheometer. For fuel gelation both organic and inorganic gellants were utilized, whereas oxidizers and simulants were gelled with addition of silica and polysaccharides, respectively. The generalized Herschel‐Bulkley constitutive model was found to most adequately represent the gels studied. Hydrazine‐based fuels, gelled with polysaccharides, were characterized as shear‐thinning pseudoplastic fluids with low shear yield stress, whereas inhibited red‐fuming nitric acid (IRFNA) and hydrogen peroxide oxidizers, gelled with silica, were characterized as yield thixotropic fluids with significant shear yield stress. Creep tests were conducted on two rheological types of gels with different gellant content and the results were fitted by Burgers‐Kelvin viscoelastic constitutive model. The effect of temperature on the rheological properties of gel propellant simulants was also investigated. A general rheological classification of gel propellants and simulants is proposed.

Rheological Characterization of Hydrogen Peroxide Gel Propellant

“…2 and 3 show a similar shear thinning trend with increase in the shear rate for the shear rate range 1 to 1000 1/s, to the reference Figure 4 [7]. The gelation of hydrogen peroxide [7] (Figure 4) was done using fine powder silica with a standard tapped density of approximately 50 g/l as a gelling agent, in a concentration ranging between 5 to 7 wt% [6,7], and it has a shear apparent viscosity range between 107 Pa.s and 100 Pa.s. Summaries of the results obtained for the apparent viscosity and yield stress of H 2 O 2 -SiO 2 gel for various temperatures are presented in Tables 1, 2, and 3.…”

“…The clear understanding of fluid flow characteristics is vital for efficient combustion, in order to gain optimum performance. As a result, a significant effort has been made worldwide to formulate, prepare, and study the rheological properties of gel propellants for various applications in rocket propulsion systems [1][2][3][4][5][6][7]. In the current study, hydrogen peroxide based gel is examined and discussed, because it is eco-friendly.…”

Literature survey for a first choice of a fuel-oxidiser couple for hybrid propulsion based on kinetic justifications

“…Apart from the reactivity aspects, the characteristics of solid fuels should be considered to ensure they can withstand the high heat load due to the combustion. This kind of consideration is found for gels dedicated to other propulsion techniques [75] but still remains absent for the hybrid rocket. For the thermal resistance, the melting temperature and the thermal conductivity are the most important data.…”

Numerical Simulation on Head-On Binary Collision of Gel Propellant Droplets

“…The physical properties of the simulant gels (non-Newtonian fluids) are from [22]. The power-law model is used to describe dynamic viscosity, the correction is as follows:…”