JAWAHARLAL NEHRU  TECHNOLOGICAL  UNIVERSITY  HYDERABAD
III Year B.Tech. AE-I Sem      L   T/P/D   C
4   -/-/-   4
(A52108) AEROSPACE PROPULSION - I

Objective:

To acquaint the student with the operating principles,construction,thermodynamic modeling and analysis of aircraft gas turbine engines and the principles components.

UNIT-I

Flight Propulsion-Aircraft Gas Turbine Engines-Generation of Trust Engine performance Parameters: History of flight propulsion, Role of reciprocating engines, operating envelope of flight vechicles.Engine operational limits.Air breathing emgines-types. Aircraft gas turbine engines-types, operating principles, distinguishing features-sehamatic diagrams, relative merits, applications. Engine components-funtion, sehamatic diagram, layout, engine station numbering. Trust generation-momentum equations. Gross, net, uninstalled, installedtrust, propulsive efficiency. Engine performance parameters-specific thrust, specific fuel consumption, total efficiency- performance trends. Effect of flight conditions, ject exit speed, exit pressure. Role of propulsion in aircraft performance. Criteria for engine selection, airframe-engine matching.

UNIT-II

Aerothermodynamic Modeling of Engine and Components- Parametric Cycle Analysis of Engines: Engine components- performance requirements, thermodynamic processes- pressure ratios, temperature ratios. Energy transfer, losses. Performance- polytropic, stage and component effciencies, burning efficiency, under and over expansion- figures of merit- significance- ideal component characteristics.

Aircraft gas turbine engines- cycle representation- turbojet, turbojet with reheat, turbofan. Computation of neft work, thermal efficiency- appication to thrust equation. Parametric cycle analysis- definition, purpose- determination of engine design performance parameters- effect of component performance, engine design choices, design constraints, flight conditions, operating parameters- determintaion of engine design point, design point performance- computation for ideal turbojet, turbofan engines. 

UNIT-III

Aircraft Engine componets- Non-Rotating- Inlets and Exhaust Nozzles, Combustion Systems- Combustors, Afterburners, Ducts and Mixers: Subsonic inlets- function, performance requirements, geometry, operating conditions, flow field, cature area, sizing. Flow distortion, diffuser losses- methods for mitigation. Performance characteristics. Supersoinic inlets- compression process, types, construction, losses, perforamnce characteristics.

Exhaust nozzles-pirmary nozzle-governing equations of flow-choking, engine back pressure control, nozzle-area ratio, thrust reversing, vectroing-mechanisms. Performance-performance maps.

Combustion process-characteristics-effects of fuel-air mixture ratio, mass flow rate, combustor. 1-D modeling of flow. Burners-types, components-funtion, schematic diagram, airflow distribution, cooling-types, cooling effectivness. Combuster porformance parameters-effect of combuster design. Fuel injection, atomisation, vaproisation, recirculation-flame stailisation, flame holders. Afterburners, funtion, components, desgin requirements, desgin parameters. The bypass duct-total pressure losses. Mixing process-pressure losses. Aircraft gas turbine engine fuels-composition, specifications of commonly used fuels.

UNIT-IV

Rotating Machinery-Axial Flow compessors,Axial Flow Turbines: Axial flow compressors-operating principle, descripition of flow feild-construction.Flow analysis-Euler's turbo machinery equations -velocity diagram analysis. Stage parameters.Flow losses-causes-efficiency, relation to total pussure loss coefficient. Axial flow turbines-similarities and differences with compressors. Veiocity diagram analysis-no exit swirl condition, flow losses-causes. Computation of stage parametersfor ideal and real compressors and turbine of given cascade blade geometry and initial flow conditions and turbine speed-procedure.

Limits on achievable performance of compressors and turbines-flow problems- surge, separation, rotating stall, wind-milling, blade stresses, temperatures-solutions-variable stators, multi-spooling, blade cooling. Operation at off desgin speeds. Range of typical axial flow compressor and turbine desgin parameters. Typical blade profiles.

UNIT-V

Performance Analysis-component Matching: Non-dimensaionalisation and correction of engine and component characteristic parameters-merits-corrected performance.Performance analysis of compressors, fan, burner, turbine, exhaust nozzle. Relation between compressors pressure ratio,mass flow rate, efficiency, engine speed. Engine control-throttle lever setting, fuel flow, burner temperature ratio, turbine speed, flow coefficient, mass flow rate-relations. Off design performance of compressors-operating line-significance, application to engine performance analysis. Engine thrust ratings.
Component matching-significance, requirements, simplifying assumptions-choked turbine and exhaustnozzle flow, constant compponent efficiencies. Turbine inlet temperature as control parameter. Engine Working lines. Effect of exhaust nozzle area, turbine inlet vane. Component matching for gas generator, turbo jet engine. Engine performance maps. Use of matching data to second stage design. Review of aircraft-engine matching.

TEXT BOOKS

1. Mattingly, J.D., Elements of gas Turbine Propulsion, MC Graw-Hill,1996, ISBN0-07-912196-9.
2. Flack, R.D., Fundamentals of jet Propulsion with Applications, cambridge University press,2005,ISBN o-521-81983-0.
3. The Jet Engine, Rolls Royce pIc, 1986, ISBN 0-902121-2-5.

REFERENCES

1. Cumpsty, N., Jet Proplusion, 2nd edn., cambridge University press,2005, ISBN 0-521-54144-1.
2. Kerrebrock,J.L., Aircraft Engines and Gas Turbines, 2nd edn.,MIT press, 1992, ISBN 0-262-11162-4.
3. Hill, P.G. and Peterson, C.R., Mechanics and Thermodynamics of Proplusion, 2nd edn., Addison Wesley, 1992.
4. Saravanamutto, H.I.H., Rogers, G.F.C. and Cohen, H., Gas Turbine Theory, 5th edn., Prentice Hall, 2001.
5. EI-Sayed, A.F., Aircraft Propulsion and Gas Turbine Engines, CRC Press, 2008, ISBN 978-0-8493-9196-5.
6. Boyce, M.P., Gas Turbine Enginerring Handbook, 2nd edn., Gulf professional Publishing, 2002, ISBN 0-88415-732-6.
7. The Aircraft Gas Turbine Engine and operation, Pratt and Whitney, 1988.
8. Oates, G.C., ed., Aerothermodynamics of Aircraft Engine components, AIAA, 1985, ISBN 0-915928-97-3.

Outcome:

The student should able to estimate the performance of the engine,and its components,in terms of the desgin choice parameters and constraints,flight conditions and engine operating conditions.