On the effect of charge channel conicity on the internal ballistic parameters of a solid-propellant rocket motor

This paper considers the influence of a charge design element, namely, the channel conicity, on the internal ballistic parameters. The case of a small conicity of the charge channel with an inclination angle of its generatrix to the channel symmetry axis of 0.5 degrees is studied. The charge channel is expanded toward its nozzle boundary. Under these conditions, the flow velocity at the nozzle boundary of the channel is 17.68% less than that in a cylindrical channel; the longitudinal pressure drop is reduced by 14.66%. The calculations performed have shown that the use of a conical charge channel instead of a cylindrical one, with an inclination angle of the charge channel generatrix to the symmetry axis equal to 0.5 degrees, allows one to significantly reduce the flow velocity at the nozzle boundary of the charge channel. This creates conditions for erosion-free combustion of solid propellants for charge with dimensions close to those of a charge with a cylindrical channel. At the same time, the longitudinal force effect on the charge is also reduced.