AIMS AND CONTENT

LEARNING OUTCOMES

The main objectives of the course are focused on the design of the different components characterizing an aircraft engine: engine inlet, compressor, combustor chamber, turbine, diffusers and nozzle.

TEACHING METHODS

Theoretical lectures and computational exercises.

SYLLABUS/CONTENT

• Performance of the engine. Analysis of the thermodynamic cycle of a turbojet engine. Pressure and temperature ratios of the cycle. Thrust and specific fuel consumption
• Layout of a turbojet engine. Definition of the main design parameters of the different engine  components.
• Engine inlet, compressor rig, combustor chamber, turbine, diffusers and nozzle, post-combustor. Analysis of the thrust characterizing the different components.
• Dimensioning and design criteria of the engine components:

1. Reduced mass flow for the dimensioning of the engine inlet. Diffuser performance chart from Sovran and Klomp. Effect of flow non uniformity on the pressure recovery and total pressure losses.
2. Design of the exit nozzle. Loss of thrust due blockage mass flow (discharge coefficient) and total pressure losses (due to boundary layer evolution). Comparison between converging and converging-diverging nozzles.
3.  Mean line design of compressors and turbines stages. Identification of the stage number. Radial equilibrium equation for the dimensioning of both compressor and turbine stages. Lieblein and Zweifel correlations for limitation of the aerodynamic loading of compressor and turbine blades, respectively. Design of compressor blades with NACA65 profiles. Design of parabolic-arc turbine profiles. Introduction to secondary flows evolution and their effects on total pressure and exit flow angle. Correlations.
4. Design of S-shaped duct. Effects of curvature radii and inlet flow unsteadiness.

• Kerrebrock and Lefebvre correlations for the determination of the total pressure losses within the combustor chamber.
• Matching of the different engine components. Off-design functioning of the engine. 

RECOMMENDED READING/BIBLIOGRAPHY

• S. Farokhi, “Aircraft Propulsion”, Wiley and Sons, 2009
• J. Mattingly, W. Heiser, D. Pratt, “Aircraft Engine Design: Second Edition”, AIAA Education Series 2002

TEACHERS AND EXAM BOARD

Exam Board

DANIELE SIMONI (President)

DAVIDE LENGANI

FRANCESCA SATTA

MARINA UBALDI

PIETRO ZUNINO

LESSONS

Class schedule

AEROENGINES

EXAMS

EXAM DESCRIPTION

Oral examination.

ASSESSMENT METHODS

The examination will be focused on two independent questions of the course. The student should be able to perform a preliminary design of each component of the aeroengine

Exam schedule