Persistent vortex generating high regression rate solid fuel grain for a hybrid rocket engine

A fuel grain for a hybrid rocket, the fuel grain comprising:

• a first fuel grain section comprising:
• a first plurality of concentric ring-shaped beads of different radii fused together to form a first disc, the first disc defining a first combustion port;
• an inner circumferential surface of each of the first plurality of circular ring-shaped beads comprising an irregular surface, such that as a ring-shaped bead forming a first combustion port wall ablates due to combustion in a combustion port, an inner circumferential surface of an adjacent ring-shaped bead comprising an irregular surface presents to form the first combustion port wall;
• a material of the first fuel grain section comprising a combustible substance;
• a second fuel grain section comprising:
• a second plurality of concentric ring-shaped beads of different radii fused together to form a second disc, the second disc defining a second combustion port;
• an inner circumferential surface of each of the second plurality of circular ring-shaped beads comprising an irregular surface, such that as a ring-shaped bead forming a second combustion port ablates due to combustion in a combustion port, an inner circumferential wall of an adjacent ring-shaped bead comprising an irregular surface presents to form the second combustion port wall;
• a material of the second fuel grain section comprising a combustible substance;
• and
• the first and second fuel grain sections bonded together and the first and second combustion ports aligned to form the fuel grain.

A hybrid rocket engine comprising:

• a fuel grain further comprising:
• a plurality of layers of fuel grain material each layer comprising a plurality of concentric ring-shaped beaded structures of different radii fused together to form a disc, the disc defining a central opening;
• the plurality of layers stacked and bonded to form a cylindrical fuel grain such that the central opening of each one of the plurality of layers is aligned to form a combustion port extending axially through the fuel grain and bounded by a boundary wall;
• wherein the fuel grain material includes at least one combustible substance;
• an inner circumferential surface of each ring-shaped beaded structure comprising an irregular surface, such that as a ring-shaped bead forming the boundary wall ablates due to combustion in the combustion port, an inner circumferential wall of an adjacent ring-shaped bead comprising an irregular surface presents to form the boundary wall;
• an oxidizer source, the oxidizer for flowing through the combustion port during engine operation;
• a valve for controlling flow of oxidizer through the combustion port;
• a nozzle in fluid communication with the combustion port;
• and
• a shell for housing the fuel grain, the oxidizer source, and the valve, the nozzle extending from the shell.