The Aerobee 150 flew on an AJ11-26 IRFNA and ANFA hypergolic pressure fed liquid motor.
We have some information to start with.
from math import pi, log
# Physics
g_0 = 9.80665 # kg.m/s^2 Standard gravity
# Chemistry
rho_rfna = 1500.0 # kg/m^3 Density of IRFNA
rho_fa = 1130.0 # kg/m^3 Density of Furfuryl Alcohol
rho_an = 1021.0 # kg/m^3 Density of Aniline
# Data
Isp = 209.0 # s Average Specific Impulse accounting for underexpantion[1]
r = 0.190 # m Radius of the tanks (OD of rocket)[2]
Burn_time = 52.0 # s Duration of the burn[2]
Mass_Fuel = 134.4 # kg Mass of the fuel burnt[1]
Mass_Ox = 343.9 # kg Mass of the oxidizer burnt[1]
First lets compute the fuel density, O/F ratio, mass flow rate, and Thrust
rho_fuel = rho_an*0.65 + rho_fa*0.35
OF = Mass_Ox / Mass_Fuel
mdot = (Mass_Fuel+Mass_Ox) / Burn_time
Thrust = mdot*g_0*Isp
print "O/F ratio: %6.1f" % OF
print "mdot: %7.2f [kg/s]" % mdot
print "Thrust: %6.1f [kN]" % (Thrust/1000.0)
O/F ratio: 2.6 mdot: 9.20 [kg/s] Thrust: 18.9 [kN]
# Mass flow for each propllent
mdot_o = mdot / (1 + (1/OF))
mdot_f = mdot / (1 + OF)
print "Ox flow: %7.2f kg/s" % mdot_o
print "Fuel flow: %7.2f kg/s" % mdot_f
def tank_length(m, rho):
l = m / (rho*pi*r*r)
return l
l_o = tank_length(Mass_Ox, rho_rfna)
l_o += l_o*0.1 # add 10% for ullage
l_f = tank_length(Mass_Fuel, rho_fuel)
l_f += l_f*0.1 # add 10% for ullage
print "Ox tank length: . . . .%7.3f m" % l_o
print "Fuel tank length: %7.3f m" % l_f
Ox flow: 6.61 kg/s Fuel flow: 2.58 kg/s Ox tank length: . . . . 2.224 m Fuel tank length: 1.231 m