Liquid rocket engines

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Launch Systems Academic Year 2016-2017 Liquid Rocket Engines (Class Exercise, 15 Nov 16) Data A LRE (Liquid Rocket Engine) operates under the following conditions  Propellant: MMH (Mono-Methyl Hydrazine)-NTO (Nitrogen Tetroxide)  Thrust at optimum expansion altitude (z* = 10000 m): T(z*) = 66000 N  Combustion chamber pressure: pc = 5.3 MPa  Burning time: tb = 460 s Consider a frozen , gas phase mixture. When needed, assume typical values for the required parameters and justify your hypotheses/assumptions. The given data depend on the parameters N, and C respectively indicatin g the alphabetical position of the first letter of candidate name and family name. Requirements 1. Preliminary engine sizing for z = z* . Evaluate the specific impulse, the nozzle throat and exhaust section areas and velocities, the initial amount and mass flow rates of fuel and oxidizer, the propellant tank volumes, the feed line (blowdown configuration), and injector head characteristics. 2. Compare the achieved thrust chamber and nozzle sizes of the MMH-NTO engine with those of a LRE working under similar operating conditions but using H2-O2 as a propellant. 3. For both systems, evaluate specific impulses and thrusts under vacuum condition (keeping the sizing results coming from the optimum expansion at z = z*). 4. Considering the MMH-NTO engine sized in 1., what is the thrust achieved under vacuum if the throat area is increased of 7% with respect to the original design value (e.g., due to erosion during the working phase)?