Engineering, 02.09.2020 04:01, zanestone12

For a solid propellant rocket motor with a sea level thrust of 207,000 lbf, determine: (a) the (constant) propellant mass flow rate and the specific impulse I at sea level, (b) the altitude for optimum nozzle expansion as well as the thrust and specific impulse at this optimum condition, and (c) at vacuum conditions. The initial total mass of the rocket motor is 50,000 Ibm and its propellant mass fraction is 0.90. The residual propellant (called silvers, combustion stops when the pressure falls below the deflagration limit) amounts to 3% of the burnt propellant. The burn time is 50 seconds, the nozzle throat area (4) is 164.2 in2 and its area ratio (A/A) is 10. The chamber pressure (pi) is 780 psia and the pressure ratio (pi/p2) across the nozzle is taken as 90.0. Neglect any start/stop transients and use the altitude data attached. a) m = 873 lbm/sec, 237 sec.
b) 13.900 ft, F-216.900 lof. 1,-248.5 sec.
c) F = 23 1,000 lbf Isp = 295 sec. 2 0.

Answers: 2

Show answers

Other questions on the subject: Engineering

Engineering, 03.07.2019 14:10, makaylashrout77

Amass of 1.5 kg of air at 120 kpa and 24°c is contained in a gas-tight, frictionless piston-cylinder device. the air is now compressed to a final pressure of 720 kpa. during the process, heat is transferred from the air such that the temperature inside the cylinder remains constant. calculate the boundary work input during this process.

Answers: 2

continue

Engineering, 03.07.2019 14:10, BardiFan

Amass of m 1.5 kg of steam is contained in a closed rigid container. initially the pressure and temperature of the steam are: p 1.5 mpa and t 240°c (superheated state), respectively. then the temperature drops to t2= 100°c as the result of heat transfer to the surroundings. determine: a) quality of the steam at the end of the process, b) heat transfer with the surroundings. for: p1.5 mpa and t 240°c: enthalpy of superheated vapour is 2900 kj/kg, specific volume of superheated vapour is 0. 1483 m/kg, while for t 100°c: enthalpy of saturated liquid water is 419kj/kg, specific volume of saturated liquid water is 0.001043m/kg, enthalpy of saturated vapour is 2676 kj/kg, specific volume of saturated vapour is 1.672 m/kg and pressure is 0.1 mpa.

Answers: 3

continue

Engineering, 04.07.2019 18:10, ahmedeldyame

Aloaded platform of total mass 500 kg is supported by a dashpot and by a set of springs of effective stiffness 72 kn/m. it is observed that when the platform is depressed through a distance x = 12.5 cm below its equilibrium position and then released without any initial velocity; it reaches its equilibrium position in the shortest possible time without overshoot. find the position and velocity of the loaded platform 0.10 sec. after its release. if a further load of 400 kg is added to the platform, find, i) the frequency of damped vibrations, and i) the amplitude of vibration after 2 complete oscillations, given that the initial amplitude is 15 cm.

Answers: 1

continue

Engineering, 04.07.2019 18:10, johnthienann58

Thermal stresses are developed in a metal when its a) initial temperature is changed b) final temperature is changed c) density is changed d) thermal deformation is prevented e) expansion is prevented f) contraction is prevented

Answers: 2

continue

Do you know the correct answer?

For a solid propellant rocket motor with a sea level thrust of 207,000 lbf, determine: (a) the (cons...