College of Engineering
Aerospace Engineering Department
BS in Aerospace Engineering
Two nozzles were designed and constructed for testing in the Cal Poly propulsion laboratory to explore which nozzle was the most capable in producing the most thrust. A 15 degree and 30 degree converging-diverging nozzles were machined and tested. Theory suggest that a bell nozzle would be the most efficient since all of the gasses generated in the combustion chamber are directed and accelerated by the throat leave the nozzle traveling along the thrust axis. All of the momentum of the gasses are directed axially thus resulting in maximum thrust. Thrust should also be produced by the converging-diverging nozzle and the hole nozzle since due to the continuity equation a decreased area should result in an increase in velocity of the flow. From the experimental tests conducted it was found that the 15 and 30-degree converging-diverging nozzles resulted in an average of 1.47 and 1.57 lbf of thrust respectively. The nozzle that produced the most thrust was the 30 degree nozzle.