Finite Area Combustor Theoretical Rocket Performance

ABSTRACTPrevious to this report, the computer program of NASA SP-273 and NASA TM-86885 was capable of calculating theoretical rocket performance based only on tileassumption of an infinite area combustion chamber (IAC). An option has been addedto this program which now also permits the calculation of rocket performance basedon the assumption of a finite area combustion chamber (FAC). In tile FAC model,the combustion process in the cylindrical chamber is assumed to be adiabatic, butnonisentropic. This results in a stagnation pressure drop from tile injector face tothe end of the chamber and a lower calculated performance for tile FAC model thanthe IAC model.INTRODUCTIONThe calculation of theoretical rocket performance involves a munber of assump-tions. For the same propellant and operating conditions, theoretical performancecan vary depending on which assumptions are used. Rocket performance calculatedby the computer program of references 1 and 2 assumes adiabatic combustion inan infinite area combustion chamber (IAC) followed by isentropic expansion in thenozzle. In order to have a more realistic model, this supplement to references 1and 2 presents an additional option for calculating rocket performance based on tile