3. Write a detailed note on the following thrust vector control methods:

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1 Code No: R Set No Starting from the first principles and with the help of neatly drawn velocity triangles obtain the following relationship: Ψ = 2 Φ (tan β 2 + tan β 3 ) where Ψ is the blade loading coefficient, Φ is the flow coefficient, β 2 and β 3 are the air angels. [16] 2. Discuss in detail about the quasi-steady and periodic fluctuating type of stresses acting on a conventional turbine blade, which could lead to crack initiation and eventual failure of the blade. [16] 3. Write a detailed note on the following thrust vector control methods: (a) Jet exhaust deflection (b) Spoilers (c) Fluid injection (d) Ball and socket type nozzle. [ ] 4. A ramjet engine operates at M = 1.5 at an altitude of 6.5 km. The diameter of the inlet diffuser at entry is 0.5 m and the stagnation temperature at the nozzle entry is 1600 K. The calorific value of the fuel used is 40 MJkg-1. The properties of the combustion gases are same as those of air, i.e. g = 1.4, R = 287 kjkg-1k-1. The velocity of air at the diffuser exit is negligible. Assuming, hd = 0.90, hb = 0.98, hj = 0.96, stagnation pressure loss in the combustion chamber = p02, calculate the following: (a) Efficiency of the ideal cycle (b) Fuel-air ratio (c) Diffuser pressure ratio (d) Propulsive efficiency (e) Nozzle pressure ratio (f) Nozzle jet Mach number (g) Thrust produced (h) Air flow rate. [16] 1 of 2

2 Code No: R Set No Explain the rocket engine principle. Classify the rockets and write their salient features. [16] 6. Explain the components of solid rockets and for which applications the rockets are used. [16] 7. (a) Compare the merits and demerits of liquid oxygen and nitric acid as rocket oxidizers. (b) Why does heat transfer increase during combustion instability? [8+8] 8. With the help of a diagram explain a typical ion propulsion system. What are the sources of losses in the system and how they are prevented? [16] 2 of 2

3 Code No: R Set No Write short notes on the following aspects related to the overall blade loss coefficient Y or λ: (a) Profile loss (b) Annulus loss (c) Secondary flow loss (d) Tip clearance loss. [ ] 2. How do you estimate gas bending stresses in a rotor blade? [16] 3. What are the modifications in the nozzle design could provide thrust vector control to the rocket vehicle. [16] 4. (a) Define Gross thrust of a ramjet engine and derive an expression for it. (b) Write a detailed note on variable geometry ramjet engine. [8+8] 5. A rocket nozzle has a throat area of 18 cm 2 and combustion chamber pressure 0f 25 bar. If the specific impulse is seconds and Weight flow rate N/s. determine (a) The thrust coefficient, (b) Propellant weight flow coefficient, (c) Specific propellant consumption, and (d) The characteristic velocity. [16] 6. Classify and explain the nozzles used in solid propellant rockets. [16] 7. Describe the construction features of propellant feeding devices for liquid rocket engines. How the positive expulsion of propellant is achieved. [16] 8. Describe the principles of electro magnetic thrusters and the ionization schemes used there in. [16] 1 of 1

4 Code No: R Set No In a single-stage impulse turbine the nozzle discharges the fluid on to the blades at an angle of 25 0 to the plane of rotation and the fluid leaves the blades with an absolute velocity of 300ms 1 at an angle of to the direction of motion of the blades. If the blades have an equal inlet and outlet angles and there is no axial thrust, estimate the blade angle, power produced per kgs 1 of the fluid. [16] 2. Discuss in detail about the quasi-steady and periodic fluctuating type of stresses acting on a conventional turbine blade, which could lead to crack initiation and eventual failure of the blade. [16] 3. Explain the basic concepts of thrust augmentation through after burning concept, and discuss in detail about the associated pressure losses. [16] 4. (a) Derive a relationship for the overall efficiency of an ideal ramjet engine. (b) How actual ramjet engine cycle deviates from an ideal ramjet engine cycle? [8+8] 5. Explain the rocket engine principle. Classify the rockets and write their salient features. [16] 6. Write notes on the following with respect to the solid propellant rocket motor: (a) Rocket motor case (b) Igniters. [8+8] 7. Explain the following with respect to liquid propellants: (a) Bipropellant (b) Storable propellants. (c) Monopropellants. (d) Thrusters. [ ] 8. What are the sub-systems of a typical electrical propulsion system? How will you relate them to solid propellant rocket motor sub systems? [16] 1 of 1

5 Code No: R Set No Explain the significance of flow coefficient and blade loading coefficient with the help of Ψ Φ diagram for a 50% reaction turbine stage. [16] 2. With the help of neat sketches, explain in detail the various methods of blade cooling. Further, explain how does the performance of a gas turbine is affected by cooling of the blades? [16] 3. Explain the basic concepts of thrust augmentation through after burning concept, and discuss in detail about the associated pressure losses. [16] 4. A ramjet is to propel an aircraft at Mach 3 at high altitude where the ambient pressure is 8.5 kpa and the ambient temperature T a is 220 K. The turbine inlet temperature T is 2540 K. If all components are ideal, i.e. frictionless determine the following: (a) The thermal efficiency (b) The propulsion efficiency (c) The overall efficiency Let the specific heat ratio (γ) be 1.4 and fuel-to-air ratio, f = [16] 5. A rocket has the following data: Propellant flow rate = 5.0 kg/s Nozzle exit diameter = 10 cm Nozzle exit pressure = 1.02 bar Ambient pressure = bar Thrust chamber pressure = 20 bar Thrust = 7 kn (a) Determine the effective jet velocity, actual jet velocity, specific impulse, and the specific impulse and the propellant consumption. (b) Recalculate the values of thrust and sp. Impulse for an altitude where the ambient pressure is 10 mbar. [16] 6. (a) Explain the salient features of a solid rocket motor with the help of a suitable diagram. (b) Explain the following with respect to the solid propellant rocket motor: i. Relationship between the burning rate and chamber pressure. 1 of 2

6 Code No: R Set No. 4 ii. Relationship between the burning rate and temperature. [8+4+4] 7. Describe the applications of small liquid thrusters in attitude control and orbit adjustments. [16] 8. Explain the different types of electric propulsion devices. What are the typical applications of electric propulsion? [16] 2 of 2