Learning outcomes of the course unit
The course aims to provide the basics for the analysis of energy systems, both through the study of the processes of conversion between different forms of energy (thermal, mechanical) as well as providing the key elements of the mechanisms of heat transfer and fluid mechanics.
To follow the course successfully requires knowledge of the contents of the courses of Calculus and Physics.
Course contents summary
Thermodynamics, fluid dynamics, heat transfer.
Thermodynamics. Basics of systems of measurement units. Introduction and definitions. Closed systems. First law of thermodynamics and internal energy. Second law of thermodynamics and entropy. Irreversibility. Theorem of not decrease of entropy. Simple one-component systems. The (p, v, T) surface and (p, v) and (p, T) diagrams. Properties of liquids. Properties and transformations of saturated and superheated vapour. Ideal gas. Properties of ideal gases. Thermodynamic diagrams (T, s) and (h, s). Simple multi-component systems. Mixtures of ideal gases. Mixtures of air and water vapour. Thermodynamic properties of mixtures of air and water vapour: title, humidity, specific enthalpy. Psychrometric chart. Dew-point temperature and adiabatic saturation. The psychrometer. Thermodynamics of open systems. Definitions. Balance equations of mass and energy. Thermodynamic cycles: Rankine cycle and cooling cycle.
Fluid Dynamics. Physical aspects of the motion of a fluid. Viscosity. Laminar and turbulent flow. Boundary layer. Material derivative. Continuity equation. Navier vectorial equation. Non dimensional form of the isothermal equations of motion. Reynolds number. External flow. D'Alembert paradox. Drag force. Motion of fluids in pipes. Integral equations of motion. Mechanical energy equation. Bernoulli's equation. Pressure drop. Measures of fluid speed and mass flow rate. Compressible fluids. Mach number. Acoustic waves equation. Compressible fluid flow in ducts with variable section. De Laval nozzle.
Heat transfer. Conduction. Fourier law. Thermal conductivity. Steady state heat conduction. Electrical analogy. Heat convection. Forced, natural and mixed convection. Energy balance equation. Non dimensional form of the non-isothermal equations of motion. Prandtl number, Grashof number, Nusselt number. Thermal radiant. Introduction and definitions. Black body radiation laws: Stefan-Boltzmann’s law, Planck's law, Wien's law, Lambert's law. Kirchhoff’s law. View factor and its properties. Mutual thermal radiation between surfaces. Simultaneous presence of different modes of heat transfer. Global heat transfer coefficient. Tube in tube heat exchanger. Thin fin.
A. Cocchi, "Elementi di termofisica generale e applicata", Società Ed. Esculapio, Bologna.
Y. A. Çengel, “Termodinamica e trasmissione del calore”, McGraw-Hill.
Assessment methods and criteria
The exam consists of a written test and an interview on three separate issues and related to the thermodynamics, fluid dynamics and heat transfer. In addition to theoretical arguments included in the program are also subject to examination application examples such as those presented during the course.