Gas Turbines

1. MEL 341 : GAS DYNAMICS & PROPULSION
P M V Subbarao
Professor
Mechanical Engineering Department
We learn this course as Gas dynamics for
Propulsion

2. Course Overview
• This undergraduate level course teaches the principles of
jet propulsion.
• The primary focus of the course is on the teaching of
thermodynamics and Gas dynamics in aircraft engines.
• The course provides information that will enable the
engineering analysis of
• ramjets and turbine engines and
• its separate components including inlets, nozzles,
combustion chambers, compressors, and turbines.

3. Course Objectives
• Students successfully completing MEL 341 will get:
• A basic understanding of thermodynamic cycles of jet
engines.
• A basic understanding of the compressible fluid flow in
inlets and compressors and turbines.
• A basic understanding of the combustion physics in
combustion chambers.
• A basic understanding of the rational behind several types
of jet engines.
• The ability to analyze jet engines; determine propulsion
efficiency and design inlets and nozzles.

4. Course Contents
• UNIT- I: PROPULSION
• Aircraft Propulsion – introduction -- Early aircraft engines --
Types of aircraft engines -- Reciprocating internal combustion
engines -- Gas turbine engines -- Turbo jet engine -- Turbo fan
engine -- Turbo-prop engine
• Aircraft propulsion theory: thrust, thrust power, propulsive and
overall efficiencies -- Problems.
• UNIT- II: THERMODYNAMIC ANALYSIS OF IDEAL
PROPULSION CYCLES
• Thermodynamic analysis of turbojet engine – Study of subsonic
and supersonic engine models -- Identification and Selection of
optimal operational parameters. Need for further development –
Analysis of Turbojet with after burner.

5. • Thermodynamic analysis of turbofan engine – Study of
subsonic and supersonic systems -- Identification and
selection of optimal operational parameters. Design of fuel
efficient engines – Mixed flow turbo fan engine – Analysis
of Turbofan with after burner.
• Thermodynamic analysis of turbo-prop engine –
Identification and selection of optimal operational
parameters.

6. UNIT –III: GAS DYNAMICS OF PASSIVE
COMPONENTS OF TURBO ENGINES
• FUNDAMENTALS OF GAS DYNAMICS : Energy equation for a
non-flow process -- Energy equation for a flow process -- The
adiabatic energy equation -- Momentum Equation --Moment of
Momentum equation -- Stagnation Velocity of Sound --Stagnation
Pressure -- Stagnation Density -- Stagnation State -- Velocity of
sound -- Critical states -- Mach number -- Critical Mach number --
Various regions of flow.
• ANALYSIS OF DIFFUSERS AND NOZZLES: Introduction –
study of intakes for subsonic and supersonic engines -- Comparison
of isentropic and adiabatic processes -- Mach number variation --
Area ratio as function of Mach numbers -- Impulse function -- Mass
flow rates -- Flow through nozzles -- Flow through diffusers –
Effect of friction -- Analysis of intakes for supersonic engines –
intakes with normal shock – oblique shocks – Study of special
supersonic nozzles and diffusers.

7. UNIT –IV: STUDY OF COMPRESSORS
• Design and Analysis of compressors – Classification –
analysis of centrifugal compressors – velocity triangles –
design of impellers and diffusers – analysis of axial flow
compressor – analysis of stage – characterization of stage –
design of multistage axial flow compressor – Performances
analysis of centrifugal and axial flow compressors.
•

8. • UNIT –V: GAS DYNAMICS OF COMBUSTORS
• Stoichimetry of combustion – calculation air-fuel ratio –
gas dynamics of combustors – thermal loading factors –
design and selection of combustors.
• UNIT –VI: STUDY OF TURBINES
• Concept of gas turbine – analysis of turbine stage –
velocity triangles and characterization of blades and stages
– Design of multistage axial flow turbine – Performance
analysis of turbines.
• UNIT –VI: ADDITIONAL TOPICS
• Thermodynamic analysis real turbo engine cycles –
performance analysis and thermodynamic optimization.
• Introduction to ramjets – study of rocket engines – study
of missile engines.

9. Books & References
• Jet Propulsion:
• Flack, R.D.., “Fundamentals of Jet Propulsion”, Cambridge University Press,
2005.
• Baskharone, E.A., “Principles of Turbomachinery in Air-Breathing Engines”,
Cambridge University Press, 2006.
• Kerrebrock J.L., “Aircraft Engines and Gas Turbines”, MIT Press, 1992.
• Mattingly, J.D., “Elements of Gas Turbine Propulsion”, McGraw-Hill Inc.,
1996.
• Gas Dynamics:
• Anderson, J.D., “Modern Compressible Flow: With Historical Perspective”,
McGrawHill, 2002.
• Zuker, R.D., and Biblarz, O.,”Fundamentals of Gas Dynamics”, John Wiley
& Sons Inc., 2002.
• Thompson, P. A. Compressible Fluid Dynamics. Maple Press Company, 1984.
• Saad, M.A.,”Compressible Fluid Flow”, Prentice-Hall, 1993.
• Liepmann, H., and A. Roshko. Elements of Gas Dynamics. John Wiley
Publishers, 1957.