Systems and methods for casting propellant grain
Systems and methods for casting solid propellants include a mandrel for forming geometric features in a perforation of a propellant grain. In various embodiments, the mandrel includes a frangible portion that is removed from the propellant grain after the propellant grain has cured around the mandrel. A second portion of the mandrel may be left behind in the propellant grain. The mandrel may include a support structured disposed in the through hole of the mandrel. The support structure may include a plurality of longitudinal channels for directed exhaust gasses through the mandrel upon ignition of the propellant grain.
1. A method for casting a solid propellant, comprising:
disposing a mandrel with respect to a casting tube, wherein a cavity is formed between the mandrel and the casting tube;
moving an uncured propellant grain into the cavity;
curing the propellant grain around the mandrel, wherein a perforation is formed in the cured propellant grain via the mandrel;
breaking a first portion of the mandrel apart from a second portion of the mandrel; and
removing the first portion from within the propellant grain, while leaving the second portion embedded in the cured propellant grain.
2. The method of claim 1 , further comprising coupling a first end cap to the casting tube.
3. The method of claim 2 , further comprising coupling a second end cap to the casting tube.
4. The method of claim 1 , further comprising:
breaking a third portion of the mandrel apart from the second portion of the mandrel; and
removing the third portion from within the cured propellant grain, while leaving the second portion embedded in the cured propellant grain.
5. A mandrel for forming a solid propellant, comprising:
an elongated body;
a through hole disposed in the elongated body; and
a support structure disposed in the through hole, wherein the support structure comprises a plurality of longitudinal walls extending from an inner surface of the elongated body in a transverse direction across the through hole, wherein each of the plurality of longitudinal walls connects at a first side and a second side to the inner surface.
6. The mandrel of claim 5 , wherein the support structure comprises a plurality of longitudinal channels.
7. The mandrel of claim 6 , wherein the support structure and the elongated body are monolithically formed with each other.
8. The mandrel of claim 7 , further comprising a non-longitudinal feature disposed on an outer surface of the elongated body.
9. The mandrel of claim 7 , further comprising a protuberant surface disposed on the elongated body.
10. The mandrel of claim 7 , further comprising a helically extending ridge disposed on an outer surface of the elongated body.
11. The mandrel of claim 5 , wherein a first wall of the plurality of longitudinal walls intersects with a second wall of the plurality of longitudinal walls.