To prepare for problems 5.79 and 5.80 use the Internet or other resources and define the following terms in the context of rocket propulsion: 

(a) Solid fuel, 

(b) Grain,

(c) Surface regression. 

Also, explain how a solid-fuel rocket engine works.

Transcribed Image Text:

5.79 An end-burning rocket motor has a chamber diameter of 10 cm and a nozzle exit diameter of 8 cm. The density of the solid propellant is 1770 kg/m, and the propellant surface regresses at the rate of 1.2 cm/s. The gases crossing the nozzle exit plane have a pressure of 10 kPa abs and a temperature of 2200C. The gas constant of the exhaust gases is 415 J/kg K. Calculate the gas velocity at the nozzle exit plane. 10 cm Problem 5.79 8 cm 5.80 A cylindrical-port rocket motor has a grain design consisting of a cylindrical shape as shown. The curved internal surface and both ends burn. The solid propellant surface regresses uniformly at 1 cm/s. The propellant density is 2000 kg/m. The inside diameter of the motor is 20 cm. The propellant grain is 40 cm long and has an inside diameter of 12 cm. The diameter of the nozzle exit plane is 20 cm. The gas velocity at the exit plane is 1800 m/s. Determine the gas density at the exit plane. Problem 5.80