Learning objectives
According to the domestic classification, “Macchine” include both fluid machinery (meant as components), and power plants (meant as primary energy converters). Intended to be a continuation of the course given at the third year (Macchine AB), this one completes the knowledge, as for theory and computational skills, required by a modern mechanical engineer.
Prerequisites
Macchine (fundamentals), i.e.: Fundamentals of Heat Engines (AKA Thermal Machines), Fundamentals of Pumps & Compressors, Fundamentals of Turbomachines
Course unit content
Lectures
Energy engineering and applied economy: fundamentals of thermal plants, cycles and pseudo-cycles, 2nd law, quality number for direct cycles, fuel types and their properties; exploitment of nuclear energy resources.
Analysis criteria for fluid machinery: Stodola's 3D plot, internal and mechanical turbine characteristic; variable-speed pump (and compressor) operation in a circuit; ideal, perfect, and semi-perfect (with polynomials) gas models; energy balance in case of combustion, high temperature dissociation, adiabatic temperature of combustion products, flame structure; fundamentals of thermal regeneration in power plants; similarity in the study of fluid machinery, 2D aerodynamics, lift and drag of wing sections.
Power plants: Sizing of hydro-power plants, regenerative steam cycles, wet steam problems and reheating; fundamentals of nuclear reactors (GCR, BWR, PWR, LMFBR), nuclear steam cycles; gas turbines, open cycle, matching of components, control techniques, off-design operation. CC power plants: topper vs bottomer power ratio, dual-pressure HRSGs, STIG. Jet and turboprop engines, thrust/power required for flying, rockets. Fundamentals of internal combustion engines, standard fuel-air cycles, volumetric efficiency, mean effective pressure, combustion process, energy balance.
Components of power plants: stage efficiency, Curtis turbine stage, 3D effects in turbines, large steam turbines and their design problems; seals, axial thrust; hydraulic turbines, types and their vector-diagrams, exhaust diffuser, cavitation; loss analysis in turbomachines; heat exchangers in steam power plants, condensers, subcooling, air condensers, cooling towers, air pre-heaters. Centrifugal pumps, theoretical and actual characteristics, radial thrust, multistage pumps, cavitation, priming, peripheral pumps, series and parallel. Turbocompressors, stall, surge, multistage compressor characteristic, operating field, choking, rotating stall; gas turbine combustors, HRSGs; reciprocating compressors, clearance volume, staging, intercooling; rotary (displacement) compressors, internal and backflow compression; reciprocating and rotary pumps, pressure ripples and dampers.
Practice
Numerical applications: operation of a pump coupled to its circuit, combined cycle power plants, CHP.
Preliminary design: Pelton and Banki turbines, HRSG, centrifugal pump, steam turbine, reciprocating compressor.
Bibliography
Textbooks
Caputo C. - Gli impianti convertitori di energia - Masson, Milano
Caputo C. - Le macchine volumetriche - Masson, Milano
Caputo C. - Le turbomacchine - Masson, Milano
To learn more:
Acton O. & Caputo C. - Collana di Macchine a fluido, 4 voll.- UTET, Torino
Haywood R.W. - Analysis of engineering cycles 3rd ed. - Pergamon press, Oxford
Horlock J.H. - Combined power plants - Krieger, Malabar
Horlock J.H. - Cogeneration - Krieger, Malabar
Lozza G. - Turbine a gas e cicli combinati - Progetto Leonardo, Bologna
Assessment methods and criteria
Written test: exercise and quizzes (2 h).
Oral test (20 min): in order to undergo the oral test, the student must have completed the written test on a scheduled date (see the official calendar).
