Problem 9: a) What is the ratio of the burning area to the nozzle area for a solid propellant motor with these characteristics? Propellant specific gravity Chamber pressure Burning rate Temperature sensitivity op Specific heat ratio Chamber gas temperature Molecular mass Burning rate exponent n 1.71 14 MPa 38 mm/sec 0.007 (K)- 1.27 2220 K 23 kg/kg-mol 0.3 b) Plot the burning rate against chamber pressure for the motor using 7 = pressures of 11 and 20 MPa. a-pi" between chamber c) What would the area ratio A/A+ be if the pressure were increased by 10%? (Use curve from b). d) Design a simple rocket motor for the conditions given above for a thrust of 5000 N and a duration of 15 sec. Determine principal dimensions and approximate weight.|