Rocket Propulsion

Subtopic: Tsiolkovsky Rocket Equation & Specific Impulse

An ideal rocket has characteristic exhaust velocity of 1200 m/s, mass flow rate of 75 kg/s, thrust coefficient of 1.5, and nozzle throat area of 0.025 m^2. The chamber pressure in kPa and the specific impulse due to gravity in seconds are ________, respectively. Assume that the acceleration due to gravity is 9.8 m/s^2.

Subtopic: Tsiolkovsky Rocket Equation & Specific Impulse

Consider a launch vehicle of mass 10 tons being launched vertically. The vehicle has 8 tons of propellant, which burns completely at a constant rate over 50 s. If the engine specific impulse is 250 s, and the acceleration due to gravity at sea level is g0, the acceleration experienced by the vehicle at lift-off is ________.

Subtopic: Tsiolkovsky Rocket Equation & Specific Impulse

An ideal two-stage rocket has identical specific impulse and structural coefficient for its two stages. For an optimized rocket, the two stages have identical payload ratio as well. The payload is 2 tons and the initial mass of the rocket is 200 tons. The mass of the second stage of the rocket (including the final payload mass) is ____ tons.

Subtopic: Tsiolkovsky Rocket Equation & Specific Impulse

A monopropellant liquid rocket engine has 800 injectors of diameter 4 mm each, and with a discharge coefficient of 0.65. The liquid propellant of density 1000 kg/m3 flows through the injectors. There is a pressure difference of 10 bar across the injectors. The specific impulse of the rocket is 1500 m/s. The thrust generated by the rocket is _____ kN (rounded off to one decimal place).

Subtopic: Tsiolkovsky Rocket Equation & Specific Impulse

A particle acted upon by a constant force 4î + ĵ - 3k̂ N is displaced from point A with position vector î + 2ĵ + 3k̂ m to point B with position vector 5î + 4ĵ + k̂ m. The work done by this force is _______ J (answer in integer).

Subtopic: Tsiolkovsky Rocket Equation & Specific Impulse

A chemical rocket with an ideally expanded flow through the nozzle produces 5 × 106 N thrust at sea level. The specific impulse of the rocket is 200 s and acceleration due to gravity at the sea level is 9.8 m/s^2. The propellent mass flow rate out of the rocket nozzle is _________ kg/s (rounded off to the nearest integer).

Subtopic: Solid, Liquid & Hybrid Rocket Engines

Two missiles A and B powered by solid rocket motors have identical specific impulse, liftoff mass of 5600 kg each, and burn durations of 30At = s and 70Bt = s, respectively. The propellant mass flow rates, Am and Bm , for missiles A and B, respectively, are given by 120 kg/s, 0 30 70 kg/s, 0 70 A B t t m m =   =   Neglecting gravity and aerodynamic forces, the relationship between the final velocities AV and BV of missiles A and B, respectively, is given by

Subtopic: Solid, Liquid & Hybrid Rocket Engines

Consider a cryogenic liquid rocket engine using an expander cycle with liquid hydrogen and liquid oxygen as the two propellants. The mass flow rate of hydrogen 2Hm into the combustion chamber is 32 kg/s , and the mass flow rate of oxygen 2Om into the chamber is such that 22 8HOmm = . The combustion of hydrogen and oxygen is at stoichiometry. Assuming that the rate of the forward reaction is much larger than that of the reverse reaction, the rate of formation of H2O is ________ kmol/s. (round off to the nearest integer) END OF QUESTION PAPER

Subtopic: Solid, Liquid & Hybrid Rocket Engines

The region of highest static temperature in a rocket engine and the region of highest heat flux are ____________, respectively.

Subtopic: Solid, Liquid & Hybrid Rocket Engines

A rocket operates at an absolute chamber pressure of $20\text{ bar}$ to produce thrust, $F_1$. The hot exhaust is optimally expanded to $1\text{ bar}$ (absolute pressure) using a convergent-divergent nozzle with exit to throat area ratio $\left(\frac{A_e}{A_t}\right)$ of $3.5$ and thrust coefficient, $C_{F,1} = 1.42$. The same rocket when operated at an absolute chamber pressure of $50\text{ bar}$ produces thrust $F_2$ and the thrust coefficient is $C_{F,2}$. Which of the following statement(s) is/are correct?

Subtopic: Solid, Liquid & Hybrid Rocket Engines

A solid propellant rocket producing 25 MN thrust is fired for 150 seconds. If the propellant mass consumed during this duration is $1.25 \times 10^6$ kg, the effective exhaust velocity (in m/s) is:

Subtopic: Tsiolkovsky Rocket Equation & Specific Impulse

A rocket engine has a sea level specific impulse of 210 s and a nozzle throat area of 0.005 m?. While testing at sea level conditions, the characteristic velocity and pressure for the thrust chamber are 1900 m/s and 50 bar, respectively. Assume the acceleration due to gravity to be 9.8 m/s?. The thrust produced by the rocket engine is kN (round off to one decimal place).

Subtopic: Solid, Liquid & Hybrid Rocket Engines

For a rocket engine, the velocity ratio $r$ is $V_a/V_e$, where $V_a$ is the vehicle velocity and $V_e$ is the exit velocity of the exhaust gases relative to the rocket. The value of $r$ at which the propulsive efficiency $\eta_p$ is maximum is _________.

Subtopic: Tsiolkovsky Rocket Equation & Specific Impulse

The specific impulse of a rocket engine is 3000 N s/kg. The mass of the rocket at burnout is 1000 kg. If the velocity increment $\Delta V$ achieved during the burn is 1500 m/s in gravity-free, drag-free space, the initial mass of the rocket (in kg) divided by 1000 is _________ (round off to 2 decimal places).

Subtopic: Tsiolkovsky Rocket Equation & Specific Impulse

A rocket has an initial mass of 150 kg. After operating for a duration of 10 s, its final mass is 50 kg. If the acceleration due to gravity is 9.81 m/s2 and the thrust produced by the rocket is 19.62 kN, the specific impulse of the rocket is

Subtopic: Tsiolkovsky Rocket Equation & Specific Impulse

Among the following engines, which one is expected to have the maximum Specific Impulse?

Subtopic: Tsiolkovsky Rocket Equation & Specific Impulse

500 students are taking one or more courses out of Chemistry, Physics, and Mathematics. Registration records indicate course enrolment as follows: Chemistry (329). Physics (186). Mathematics (295). Chemistry and Physics (83). Chemistry and Mathematics (217). and Physics and Mathematics (63). How many students are taking all 3 subjects?

Subtopic: Solid, Liquid & Hybrid Rocket Engines

A single stage chemical rocket, having an initial mass of 10,000 kg and structural mass (burnout mass) of 2000 kg, uses a propellant with an effective exhaust velocity of 2500 m/s. The maximum velocity increment $\Delta V$ (in km/s) of the rocket in gravity-free, vacuum space is _________ (round off to 2 decimal places).

Subtopic: Solid, Liquid & Hybrid Rocket Engines

In a particular rocket engine, helium propellant is heated to 6000 K and 95% of its total enthalpy is recovered as kinetic energy of the nozzle exhaust. Consider helium to be a calorically perfect gas with specific heat at constant pressure of 5200 J/kgK. The exhaust velocity for such a rocket for an optimum expansion is _____ m/s.

Subtopic: Tsiolkovsky Rocket Equation & Specific Impulse

A rocket, with a total lift-off mass of 10000 kg, moves vertically upward from rest under a constant gravitational acceleration of 9.81 m/s^2. The propellant mass of 8400 kg burns at a constant rate of 1200 kg/s. If the specific impulse of the rocket engine is 240 s, neglecting drag, the burnout velocity in m/s is

Subtopic: Solid, Liquid & Hybrid Rocket Engines

A rocket nozzle is designed to produce maximum thrust at an altitude, H = 8 km from the sea level. The nozzle operates 1n

Subtopic: Tsiolkovsky Rocket Equation & Specific Impulse

A small rocket having a specific impulse of 200s produces a total thrust of 98kN, out of which 10kN is the pressure thrust. Considering the acceleration due to gravity to be 9.8m/s^2, the propellant mass flow rate in kg/s is

Subtopic: Solid, Liquid & Hybrid Rocket Engines

A stationary two stage rocket with initial mass of 16000kg, carrying a payload of 1000kg, is fired in a vertical trajectory from the surface of the earth. Both the stages of the rocket have same specific impulse, Isp, of 300s and same structural coefficient of 0.14. The acceleration due to gravity is 9.8m/s^2. Neglecting drag and gravity effects and considering both the stages with same payload ratio, the terminal velocity attained by the payload in m/s is __________________.

Subtopic: Tsiolkovsky Rocket Equation & Specific Impulse

A cryogenic rocket has a specific impulse of 455s and characteristic velocity of 2386 m/s. The value of thrust coefficient for this rocket is

Subtopic: Solid, Liquid & Hybrid Rocket Engines

Which of the following design parameters influence the maximum rate-of-climb for a jet-propelled airplane? P. Wing loading Q. Maximum thrust-to-weight ratio R. Zero-lift drag coefficient S. Maximum lift-to-drag ratio

Subtopic: Solid, Liquid & Hybrid Rocket Engines

A rocket motor has a chamber pressure of 100 bar and chamber temperature of 3000 K. The ambient pressure is 1 bar. Assume that the specifi c heat at constant pressure is 1 kJ/kg-K. Also assume that the flow in the nozzle is isentropic and optimally expanded. The exit static temperature in K is

Subtopic: Tsiolkovsky Rocket Equation & Specific Impulse

Thrust of liquid oxygen - liquid hydrogen rocket engine is 300 kN. The O/F ratio used is 5. If the fuel mass flow rate is 12.5 kg/s, the specific impulse of the rocket motor in Ns/kg is

Subtopic: Tsiolkovsky Rocket Equation & Specific Impulse

Consider two rockets P and Q fired vertically up wi th identical specific impulse and a payload of 2 kg. Rocket P has 2 identical stages, and each stage has 200 kg of propellant and 20 kg of structural weight. Rocket Q has a single stage with 400 kg of propellant and 40 kg of structural weight. Neglecting drag and gravity effects, the ratio of the change in velocity of P to that attained by Q is (A) 1.13 (B) 1.23 (C ) 1.33 (D) 1.43 Common Data Questions Common Data for Questions 48 and 49: Data for an airplane are given as follows: weight 30Wk N , thrust available at sea-level 0 4000TN , wing planform area 230Sm , maximum lift coefficient max 1.4LC  , and drag coefficient 20.015 0.024 .D LCC Assume air density at sea-level 31.22 /kg m  .

Subtopic: Solid, Liquid & Hybrid Rocket Engines

Mahatama Gandhi was known for his humility as

Subtopic: Tsiolkovsky Rocket Equation & Specific Impulse

A rocket is to be launched from the bottom of a very deep crater on Mars for earth return. The specific impulse of the rocket, measured in seconds, is to be normalized by the acceleration due to gravity at

Subtopic: Solid, Liquid & Hybrid Rocket Engines

A rocket motor has combustion chamber temperature of 2600 K and the products have molecular weight of 25 g/mol and ratio of specific heats 1.2. The universal gas constant is 8314 J/kg-mole-K. The value of theoretical c* (in m/s) is ____.

Subtopic: Solid, Liquid & Hybrid Rocket Engines

A solid propellant of density 1800 kg/m 3 has a burning rate law r = 6.65 x 10 -3p0.45 mm/s, where p is pressure in Pascals. It is used in a rocket motor with a tubular grain with an initial burning area of 0.314 m^2. The characteristic velocity is 1450 m/s. What should be the nozzle throat diameter to achieve an equilibrium chamber pressure of 50 bar at the end of the ignition transient?

Subtopic: Solid, Liquid & Hybrid Rocket Engines

A bipropellant liquid rocket motor operates at a ch amber pressure of 40 bar with a nozzle throat diameter of 50 mm. The characteristic velocity is 1540 m/s. If the fuel-oxidizer ratio of the propellant is 1.8, and the fuel density is 900 kg/m^3, what should be the minimum fuel tank volume for a burn time of 8 minutes

Subtopic: Solid, Liquid & Hybrid Rocket Engines

The propellant in a single stage sounding rocket occupies 60% of its initial mass. If all of it is expended instantaneously at an equivalent exhaust velocity of 3000 m/s, what would be the altitude attained by the payload when launched vertically? [Neglect drag and assume acceleration due to gravity to be constant at 9.81 m/s^2.]

Subtopic: Solid, Liquid & Hybrid Rocket Engines

Choose the most appropriate alternative from the options given below to complete the following sentence: The administrators went on to implement yet another unreasonable measure, arguing that the measures were already ___ and one more would hardly make a difference.

Subtopic: Solid, Liquid & Hybrid Rocket Engines

Multi-staging in rockets improves the burn-out performance by increasing mainly stage-wise (A) payload mass ratios (B) structural mass efficiencies

Subtopic: Solid, Liquid & Hybrid Rocket Engines

For a solid rocket motor, the burn rate r of propellant obeys Saint-Robert's law r = a * p_c^n. For stable combustion without motor overpressure explosion, the pressure exponent n must be:

Subtopic: Tsiolkovsky Rocket Equation & Specific Impulse

The specific impulse I_sp of a rocket engine is defined as:

Subtopic: Solid, Liquid & Hybrid Rocket Engines

Choose the word or phrase that best completes the sentence below. ______________ in the frozen wastes of Arctic takes special equipment.

Subtopic: Solid, Liquid & Hybrid Rocket Engines

Impulse is maximum for a

Subtopic: Solid, Liquid & Hybrid Rocket Engines

designed in such a way that the payload ratio and the structural ratio are same for both the stages The second stage of the rocket has following mass distribution : Propellant Mass = 10208 kg Structural Mass = 1134 kg Payload Mass = 1700 kg 8, =9.8 m/s If the rocket is fired from rest and it flies in a zero gravity field and a drag free environment, the final velocity attained by the payload is

Subtopic: Tsiolkovsky Rocket Equation & Specific Impulse

The performance of a solid rocket motor is improved by replacing the old propellant with a new one. The new propellant gives a combustion temperature 40% higher than the previous propellant without appreciable change in molecular weight of combustion products and other operating parameters. By approximately what percentage is the specific impulse of the new motor higher than the old one ?

Subtopic: Solid, Liquid & Hybrid Rocket Engines

In a convergent-divergent (CD) nozzle of a rocket motor, the wall heat flux is maximum at

Subtopic: Tsiolkovsky Rocket Equation & Specific Impulse

The correct order of increasing specific impulse is

Subtopic: Tsiolkovsky Rocket Equation & Specific Impulse

An aircraft is cruising at a true air speed (TAS) of 100 m/s under ISA conditions, at an altitude at which the density of free stream is 0.526 kg/m'. What will be the equivalent air speed (EAS)?

Subtopic: Solid, Liquid & Hybrid Rocket Engines

The initial temperature sensitivity of burn rate of a solid rocket motor propellant is positive. If the initial temperature increases then

Subtopic: Solid, Liquid & Hybrid Rocket Engines

The maximum value of c for safe loading of the structure, based on von-Mises failure criterion is

Subtopic: Solid, Liquid & Hybrid Rocket Engines

Neglecting gravity and drag effects, if the initial velocity of the liquid rocket engine is 2.5 km/s, the velocity of the rocket at burnout is

Subtopic: Solid, Liquid & Hybrid Rocket Engines

If this motor is fired to give a speed increment of 500 m/s along the direction of motion, the mass of propellant consumed is:

Subtopic: Tsiolkovsky Rocket Equation & Specific Impulse

Which one of the following values is nearer to the vacuum specific impulse of a rocket engine using liquid hydrogen and liquid oxygen as propellants?