AE 2304 PROPULSION-II prepared By Mr. Suresh Chandra Khandai

1. AE 2304PROPULSION-IIpreparedByMr. Suresh Chandra Khandai

2. UNIT-I AIRCRAFT GAS TURBINES • Impulse and reaction blading of gas turbines • Velocity triangles and power output • Vortex theory • Choice of blade profile, pitch and chord • Estimation of stage performance • Limiting factors in gas turbine design • Methods of blade cooling • Matching of turbine and compressor. • Numerical problems • University question paper solution

3. Gas Turbines • Work can be extracted from a gas at higher inlet pressure to the lower back pressure by allowing it to flow through the turbine. • The work done by the gas is equivalent to the change of its enthalpy.

4. Impulse turbines • An impulse stage is characterized by the expansion of the gas which occurs only in the stator nozzles. • The rotor blades act as directional vanes to deflect the direction of the flow. • They convert the K.E. of the gas into work by changing the momentum of the gas more or less at constant pressure.

5. Reaction turbines • A reaction stage is one in which expansion of the gas takes place both in the stator & in the rotor. • The function of the stator is the same as that of the impulse stage, but the function of the rotor is in two folds

6. Methods of blade cooling • Convection cooling works by passing cooling air through passages internal to the blade. Heat is transferred by conduction through the blade, and then by convection into the air flowing inside of the blade. A large internal surface area is desirable for this method, so the cooling paths tend to be serpentine and full of small fins.[

7. A variation of convection cooling, impingement cooling, works by hitting the inner surface of the blade with high velocity air. This allows more heat to be transferred by convection than regular convection cooling does. Impingement cooling is often used on certain areas of a turbine blade, like the leading edge, with standard convection cooling used in the rest of the blade.

8. The second major type of cooling is film cooling . This type of cooling works by pumping cool air out of the blade through small holes in the blade. This air creates a thin layer (the film) of cool air on the surface of the blade, protecting it from the high temperature air. The air holes can be in many different blade locations, but they are most often along the leading edge.

9. Transpiration cooling, the third major type of cooling, is similar to film cooling in that it creates a thin film of cooling air on the blade, but it is different in that that air is "leaked" through a porous shell rather than injected through holes. This type of cooling is effective at high temperatures as it uniformly covers the entire blade with cool air. • Transpiration-cooled blades generally consist of a rigid strut with a porous shell. Air flows through internal channels of the strut and then passes through the porous shell to cool the blade.

10. UNIT-II RAMJET PROPULSION • Operating principle of Ram jet engine • Sub critical, critical and supercritical operation of Ramjet • Combustion in Ramjet engine • Ramjet performance • Ramjet design calculations • Introduction to scramjet. • Numerical Problems • University question paper solution

11. RAMJET ENGINE

14. SCRAMJET

15. UNIT-III FUNDAMENTALS OF ROCKET PROPULSION • Operating principle • Specific impulse of a rocket - Derivation • Internal ballistics of rocket engines • Rocket nozzle classification - Explanation • Rocket performance considerations • Numerical problems • University question paper solution

16. SOLID PROPELLANT ROCKET MOTOR

17. DESIGN • Design begins with the total impulse required, which determines the fuel/oxidizer mass. Grain geometry and chemistry are then chosen to satisfy the required motor characteristics. • The following are chosen or solved simultaneously. The results are exact dimensions for grain, nozzle, and case geometries. • The grain burns at a predictable rate, given its surface area and chamber pressure. • The chamber pressure is determined by the nozzle orifice diameter and grain burn rate. • Allowable chamber pressure is a function of casing design.

18. The length of burn time is determined by the grain 'web thickness'. • The grain may or may not be bonded to the casing. Case-bonded motors are much more difficult to design, since the deformation, under operating conditions, of the case and the grain must be compatible.

19. UNIT-IV CHEMICAL ROCKETS • Solid propellant rockets – Selection criteria of solid propellants • Hardware components of solid rockets – Propellant grain design considerations • Liquid propellant rockets – Selection of liquid propellants • Cooling in liquid rockets • Hybrid rockets • Numerical problems • University question paper solution

20. LIQUID ROCKET MOTOR

23. UNIT-V ADVANCED PROPULSION TECHNIQUES • Electric rocket propulsion • Ion propulsion techniques • Nuclear rocket • Solar sail • Concepts in nozzleless propulsion • Numerical problems • University question paper solution • Revision

24. Electric rocket propulsion • ELECTRO THERMAL • ELECTRO MAGNETIC(PLASMA THRUSTERS) • ELECTRO STATIC(ION PROPULSION

25. ELECTRO THERMAL PROPULSION Electro-thermal propulsion systems are those systems in which electrical energy is used to heat propellants, thus producing thrust. Principle Electro-thermal systems heat propellants , which produce gases. The gases are then sent through a supersonic nozzle to produce thrust.

28. Ion propulsion Technique • This technique of propulsion utilizes electrostatic energy, i.e. energy due to electric charges on materials is used to propel rockets. Since ions are used for this, the technique is also called as ion propulsion technique.

30. Nuclear Rocket • Nuclear energy is used as propellant.

31. Solar sail

32. NOZZLELESS PROPULSION Nozzleless solid propellant rocket motor

33. THE END