UNIT V

ROCKET PROPULSION

SYLLABUS

(X)* First halfTypes of rocket engines – Propellants-feeding systems – Ignition andcombustion – Theory of rocket propulsion(Y)*Second HalfPerformance study – Staging – Terminal and characteristic velocity –Applications – space flights.

PART – A

VVXX11.. How a rocket propulsion system works?

VVXX22.. Compare solid and liquid propellant rockets.

VVXX33.. Name some oxidizers used in rockets.

VVXX44.. What is hypergolic?

VVXX55.. Mention any four specific applications of rocket.

VVXX66.. What is bi-propellant? Give example.

VVXX77.. What is the role of inhibitors in rocket propulsion system? (Or) What is the use of

inhibitors in solid propellants?

VVXX88.. What is mono-propellant? Give examples.

VVXX99.. Classify the rocket engines.

VVXX1100.. What are the properties of solid propellants?

VVXX1111.. Define characteristic velocity.

VVXX1122.. Why rocket is called as non breathing engine? Can rocket work at vacuum?

VVXX1133.. What are the requirements of good liquid propellants?

VVXX1144.. What are the advantages of a hybrid rocket?

VVXX1155.. What are the types of rocket engines based on source of energy employed?

VVXX1166.. Explain chemical rocket propulsion system.

VVXX1177.. What is meant by restricted burning in rockets?

VVXX1188.. Define the terms UDMH, RFNA, JATO and RATO.

VVYY11.. A rocket flies at 10080 km/hr with an effective exhaust jet velocity of 1400 m/sec, and

the propellant flow rate of 5 kg/sec. Find the propulsion efficiency and propulsion power

of the rocket.

VVYY22.. Give some important requirements of rocket engine fuels.

VVYY33.. What is meant by effective jet velocity?

VVYY44.. Define thrust co-efficient.

VVYY55.. What is mass ratio? How does it affect rocket velocity gain?

VVYY66.. Define thermal efficiency.

VVYY77.. Define propulsive efficiency.

VVYY88.. Define thrust.

VVYY99.. What is weight flow co-efficient?

VVYY1100.. What is specific impulse of rocket?

VVYY1111.. Define specific propellant consumption.

VVYY1122.. What is IWR?

PART – B

VVXX11.. (i) Draw and explain various types of burning configuration of a solid propellant.

(ii) Compare the performances of propellant pump feed system and gas feed system.

VVXX22.. List the main components of Liquid Propellant Rocket engine and expalin.

VVXX33.. Describe with a schematic diagram the principle of working and construction of a

magneto hydrodynamic rocket engine.

VVXX44.. What are the advantages and disadvantages of liquid propellant rocket engine.

VVXX55.. Explain the working principle of a Turbo-pump feed system with a schematic diagram for

liquid propellant rocket engine.

VVXX66.. Describe briefly the important applications of rocket propulsion in the following fields

1. Aircrafts

2. Militry

3. Space

4. Scientific

VVXX77.. Draw a neat sketch explaining the general working of the hybrid propellant rocket.

VVXX88.. (i) Comparison between solid and liquid propellant propulsion.

(ii) List out the important properties of solid propellants.

VVXX99.. Enumerate the differences between a mono propellant and bi propellant.

VVXX1100.. Explain briefly about the propellant feed system of a liquid propellant rocket engine with

suitable schematic sketches.

VVXX1111.. What is gas pressurization and its purpose in rocket engines? Describe with the aid of a

sketch.

VVXX1122.. (i) What is regenerative heating of a propellant in a liquid propellant rocket?

(ii) What is the purpose of injectors in rocket engines? Describe an injector with the aid

of a sketch.

VVXX1133.. (i) What are the various methods of ignition employed in liquid propellant rockets?

(ii) What is ignition delay?

(iii) Describe the events leading to pressure oscillations in a rocket combustor.

VVYY11.. The following conditions refer to a rocket:

Propellant flow rate = 193 kg/s,

Nozzle exit diameter = 600 mm,

Nozzle exit pressure = 1.1 bar,

Ambient pressure = 1.013 bar,

Thrust chamber pressure = 37 bar,

Thrust produced = 380 kN.

Find the effective jet velocity, jet velocity, specific impulse, total impulse and the SPC.

VVYY22.. A rocket engine has the following data:

Effective jet velocity = 1200 m/s,

Flight to jet speed ratio = 0.82

Oxidizer flow rate = 3.4 kg/s,

Fuel flow rate = 1.2 kg/s and

Heat of reaction per kg of the exhaust gases = 2520 kJ/kg.

Calculate the following:

i. Thrust

ii. Specific impulse

iii. Propulsive efficiency

iv. Thermal efficiency

v. Overall efficiency

VVYY33.. In rocket engine, propellant flow rate is 5.5 kg/s, nozzle exit diameter is 9 cm, nozzle exit

pressure is 1.02 bar, ambient pressure is 1.013 bar, thrust chamber pressure is 22 bar and

thrust is 7.2 kN. Calculate the following: (i) Effective jet velocity (ii) Actual jet velocity

(iii) Specific impulse and (iv) Specific propellant consumption.

VVYY44.. A rocket has the following data : Combustion chamber pressure = 36 bar, Combustion

chamber temperature = 3600 K, Oxidizer flow rate = 41 kg/s, Mixer ratio = 5 and

Ambient pressure = 585 N/m2. Determine

i. Nozzle throat area

ii. Thrust

iii. Thrust co-efficient

iv. Characteristic velocity and

v. Exit velocity of exhaust gases.

Take γ = 1.3 and R = 287 J/kg K.

VVYY55.. A rocket operating at an altitude of 19 km with the following data:

Propellant flow rate = 1 kg/s

Thrust chamber pressure = 25x105 N/m2

Thrust chamber temperature = 2500 K

Nozzle area ratio = 10.12

Calculate (i) Thrust (ii) Effective jet velocity (iii) Specific impulse.

Take γ = 1.3 and R = 355 J/kg K.

VVYY66.. A rocket engine has the following data. Combustion chamber pressure is 38 bar,

combustion chamber temperature is 3500 K, oxidizer flow rate is 41.67 kg/s, mixture

ratio is 5, and the properties of exhaust gases are Cp/Cv = 1.3 and R = 0.287 kJ/kg K. The

expansion takes place to the ambient pressure of 0.0582 bar. Calculate the nozzle throat

area, thrust, thrust co-efficient, exit velocity of the exhaust and maximum possible

exhaust velocity.

VVYY77.. A rocket flies at 10,080 kmph with an effective exhaust jet velocity of 1400 m/s and

propellant flow rate of 5.0 kg/s. If the heat of the reaction of the propellant is 6500 kJ/kg

of the propellant mixture determine (i) the propulsive efficiency and power (ii) engine

output and thermal efficiency and (iii) overall efficiency.

VVYY88.. Calculate the orbital and escape velocities of a rocket at mean sea level and an altitude of

300 km from the following data:

Radius of earth at mean sea level = 6341.6 km

Acceleration due to gravity at mean sea level = 9.809 m/s2

VVYY99.. A rocket has the following data: Propellant flow rate = 5 kg/s, Nozzle exit diameter = 10

cm, Nozzle exit pressure = 1.02 bar, Ambient pressure = 1.013 bar, Thrust chamber

pressure = 20 bar, Thrust = 7 kN. Determine the effective jet velocity, actual jet velocity,

specific impulse and the specific propellant consumption. Recalculate the values of thrust

and specific impulse for an altitude where the ambient pressure is 10 mbar.

VVYY1100.. A projectile has the following data: Initial mass = 200 kg; mass of propellants = 70 kg;

operating period = 3s; average specific impulse = 2400 Ns/kg. Find the mass ratio of the

vehicle, propellant mass fraction, vehicle acceleration and total impulse.

VVYY1111.. A rocket has an initial mass of 3600 kg at take off. The effective jet velocity for the

duration of powered flight of 80 seconds remains constant at 2070 m/s. The maximum

velocity of the rocket during the flight (assumed vertical) is twice the effective jet

velocity. Calculate the flow rate of the propellants, thrust in kilo Newton and the values

of the altitude gains during powered and coasting flights.