ADVANCED HEAT ENGINES
Learning outcomes of the course unit
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.
Macchine (fundamentals), i.e.: Fundamentals of Heat Engines (AKA Thermal Machines), Fundamentals of Pumps & Compressors, Fundamentals of Turbomachines
Course contents summary
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.
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.
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).