ABSTRACT
The design of the solid propellant grain is a decisive aspect of the solid propellant
rocket motor performance. Tubular grain design is a favorable design since it
produces a high neutral thrust profile. However, neutrality of tubular grains
deteriorates as the aspect ratio of the grain deviates from an optimum value that is
dependent on the web thickness. In some cases, the undesirable phenomenon of
erosive grain burning may take place. One simple solution to restore neutrality is to
add taper to the ends of the grain. Loss of motor filling comes as penalty for adding
these tapered ends. The grain should thus be tailored to simultaneously satisfy both
desired design objectives namely, neutrality and filling.
The present paper aims to address the dependence of these two design objectives
on the design of a taper-ended tubular grain. The designs that are likely to yield
erosive burning are also addressed. A parametric study is conducted involving the
aspect ratio of the grain, its web thickness, and the taper angles on both ends.