Answer Happy

a) For a stoichiometric mixture, which bi-propellant combination of liquid oxidizer and liquid fuel . has the highest specific impulse amongst the liquid rocket propellants? [2 marks] b) Name any two (out of six) types of the liquid rocket engine cycles? [4 marks] c) Which chemical substance is primarily used as oxidiser in contemporary composite solid rocket propellants? What is the chemical formula of the substance in question? [4 marks] d) The solid rocket motor (SRM) shown on the Figure 2-1, has two-stage end-burning propellant grain, i.e. the propellant grain with the “booster" and the “sustainer" part (stage) of the propellant grain. The first stage, or the booster stage, has constant burning surface Sb1 = Sb = const and the web thickness W1= w. The second stage, or the sustainer stage, has S, the burning surface Sb2= = const and the web thickness w2= 2w. Propellant for both 2 burning stages is same, with exponent coefficient in burning pressure law n=0.5. The nozzle is without a divergent part (At=Aexit, Eexit = 1). Inhibited A = Aexit Sustainer part of the propellant grain Booster part of the propellant grain Sb=const 2w w Sb=const 2 Figure 2-1: Scheme of propellant grain for Question 2 [5 marks] [5 marks] In this question, you should calculate the following ratios: P. (i) the pressure ratio between booster and sustainer stage P2 (ii) the burning time ratio between booster and sustainer stage 1 12 F (iii) the thrust ratio between booster and sustainer stage F Useful equations: S, Equation of equilibrium combustion pressure inside SRM: P = .P.C.b A [5 marks] -.) " Burning rate Law: r =b.P”. Burning rate Law in general form Thrust: F = Cp.P.A, F Specific impulse: Isp = (Perie - Pa)=Lexie + C :& Perie - Pa) m Aexit = =U exit + m Pc