Flow of Gel Fuels in Tapered Injectors

The governing equations of the steady flow of gel propellants and fuels in a tapered tube injector were formulated assuming a power-law rheological model. A parametric investigation was conducted to evaluate the effect of the injector geometry and pressure gradient on the flow rate and the mean apparent viscosity of the gel for various fuels and metal loadings. The theoretical results indicate that the flow rate increases significantly with decreasing power-law index and with increasing pressure drop in the injector. The apparent viscosity is not uniform in each cross section; it is maximal at the axis and reaches minimum at the wall. The mean apparent viscosity of the gel exhibits a significant decrease with increasing convergence angle of the injector. This implies that to obtain better atomization of the gel, high convergence angles are required. A comparison between RP-1/Al gels with various aluminum mass fractions was made. The results indicate the existence of an optimal metal loading. (Author)