08081 - Turbomachinery

Academic Year 2015/2016

  • Docente: Fabrizio Ponti
  • Credits: 6
  • SSD: ING-IND/08
  • Language: Italian
  • Teaching Mode: Traditional lectures
  • Campus: Forli
  • Corso: First cycle degree programme (L) in Aerospace Engineering (cod. 8263)

Course contents

Basic knowledge
Classification of machinery.
Water as a potential fluid: characteristics and Ts and hs diagrams.
Conservation of mass. Energy conservation: first principle for a closed system and for an open system (mechanical and thermal). Entropy and enthalpy.
Ideal gas and ideal fluid: definition, major transformations and their representation on the Ts, hs diagrams. Work  and efficiency, polytropic and isentropic efficiency for a compression and an expansion.
Combustion: definition of stoichiometric air, excess air, lower heating value.

Gas turbine thermodynamic cycle
Generality, Brayton cycle, simple plant configuration and  cycle representation on the diagram Ts. Conditions for the representability of the cycle in the Ts diagram. Thermodynamic analysis of gas turbine self-sustaining condition. Assessment of performance. Condition of maximum useful work and maximum efficiency.
Regenerative cycle, thermodynamic diagrams, problems and limitations in employment.
Cycle  with separated compression phases (inter-cooling): Schematic diagram and thermodynamic conditions. Complete inter-cooling, condition of maximum useful work, problems and limitations in employment.
Post-combustion cycle: Schematic diagram and thermodynamic process.
Turbine blades cooling: techniques and evaluation of the needed cooling mass flow rate, typical blades materials.
Centrifugal compressor: specific work and efficiency. Compressors and turbines performance representation.
Axial compressor: velocity triangles, specific work and efficiency. Surge, chocking. Inducer. Starting problems for axial compressors. Compression refrigeration cycle
Definition of COP. Cycle at saturated vapor compression cycle (biphasic with intercooler, dual-separator, dual-separator with bubbler), biphasic compression cycle with two temperatures of vaporization. Characteristics of fluids for refrigeration equipment and their classification.
Applications of refrigeration cycles to liquefaction of hydrogen and oxygen.

Readings/Bibliography

Sistemi energetici e loro componenti, 2a ed., G. Negri di Montenegro, M. Bianchi, A. Peretto, Pitagora Editrice Bologna

Teaching methods

Theaching is organized in class lectures and numerical exercises

Assessment methods

The final exam will be a discussion on the topics presented in class

Teaching tools

The slides used by the teacher are available.

Office hours

See the website of Fabrizio Ponti