Dana Lattibeaudiere February 21, 2008 Propulsion Nozzle Design Injectors Assistance from Nicole Wilcox & Stephen Bluestone AAE 450 Spring 2008
Nozzle Design CEA code Addition –Pe/Pc ratio as input – varied Pc, O/F for each prop –Output parameters: c*, ɛ, γ, Tc, M, a Assumption: –Exit Pressure = 48,263 Pa – Reason: Find ɛ AAE 450 Spring 2008
Injectors: AAE 450 Spring 2008 Propulsion What are those? Who cares? Cost:~30% of total engine cost Recommendations: –Liquid Propellants: unlike, impinging type of injector –Hybrid Propellants: Injects ox directly down the port –91 – 93 % combustion efficiency Injects ox into a pre-combustion chamber
AAE 450 Spring 2008 Backup Slides Propulsion O_F3 Pc (MPa) Ae/Atc*cfIsp_vacIspPc/PegamaMTc EXAMPLE: Selected this chamber pressure and O/F = 3 for LOX/LH2 case because there wasn’t much of a loss in Isp as Pc increased. Addition of mass is something we wanted to avoid. O_F3Pc (MPa)2.413 Ae/Atc*cfIsp_vacIspPc/PegamaMTc O_F3Pc (MPa)2.758 Ae/Atc*cfIsp_vacIspPc/PegamaMTc
References Humble, R. W., Henry, G. N., Larson, W. J., Space Propulsion Analysis and Design, McGraw-Hill, New York, NY, Sutton, G. P., Rocket Propulsion Elements, Wiley & Sons, INC., New York, NY, AAE 450 Spring 2008