29243 - Technical Physics T

Learning outcomes

Aim of the course is to provide students with the theoretical and practical means needed to set up and solve the following problems: energy balance problems of thermodynamic systems; fluid flow problems in ducts, with or without machinery, both in laminar flow and in turbulent flow; steady-state conduction problems in simple geometries, even with internal power generation; simple convective heat transfer problems; simple radiative heat transfer problems; combined heat transfer problems. Moreover, the main thermodynamic cycles and the main industrial applications of the theory presented are discussed in detail.

Course contents

Applied Thermodynamics

Introduction and definitions - First law and energy - Second law and entropy - Thermodynamic temperature - Simple systems - Gibbs equation - Phase rule - Energy balance for a control volume - Simple closed systems with a single chemical constituent - Specific heat capacity - Equation of state and diagrams {p,T}, {p,v}, {T,s}, {h,s}, {p,h} - Ideal gases: Joule's law; internal energy, enthalpy and entropy changes - Properties of liquids (outlines) - Properties of saturated vapors - Properties of superheated vapors and of real gases (outlines) - Direct thermodynamic cycles: Rankine, Brayton-Joule, Otto, Diesel - Inverse thermodynamic cycles: vapor compression cycle - Air and vapour mixtures - Psychrometric charts - Main thermodynamic processes of air and vapour mixtures.

Fluid Dynamics

Definitions - Laminar and turbolent flows - Dynamic boundary layer - Viscosity - Main equations of isothermal flow: continuity equation and Navier-Stokes equations - Simple cases of laminar flow - Isothermal flow inside ducts: governing equations - Head losses - Friction factor - Moody diagram - Total dynamic head of pumps and fans.

Heat Transfer

Conduction: Fourier's law - Fourier's equation - Simple cases of steady-state conduction in cartesian and cylindrical coordinates - Thermal resistance - Thermal resistances in series and in parallel - Steady-state conduction with internal heat generation - Thermoelectric effects: Seebeck and Peltier.

Convection: Forced, free and mixed convection flows - Main equations for non isothermal flows - Newton's law - Heat transfer coefficient and Nusselt number - Dimensionless equations and relationships Nu = Nu (Re, Gr, Pr) for mixed convection - Thermal boundary layer - Forced convection: relationship Nu = Nu (Re, Pr) - Free convection: relationship Nu = Nu (Gr, Pr).

Radiation: Introduction and definitions - Laws: Kirchhoff, Stefan-Boltzmann,  Planck, Wien, Lambert - Gray surfaces - Heat exchange by radiation between black and gray surfaces.
Combined heat transfer problems: Introduction - Total thermal resistance and overall heat transfer coefficient - Finned surfaces.

Readings/Bibliography

The handwritten notes taken during the lessons and the material given by the teacher are enough to prepare for the exam. In order to achieve a deeper knowledge of some topics or for self-study, the following books are suggested.

Suggested books:

1- Çengel Y. A., Termodinamica e trasmissione del calore, McGraw-Hill, Milano, 2013 (quarta edizione).

2- Lazzari S., Pulvirenti B., Rossi di Schio E., Esercizi risolti di Termodinamica, Moto dei Fluidi e Termocinetica per i nuovi Corsi di Laurea in Ingegneria, Esculapio, 2008 (terza edizione).

3- Zanchini E., Termodinamica, Pitagora, Bologna, 1993.

4- Cocchi A., Elementi di termofisica generale ed applicata, Progetto Leonardo, Società Editrice Esculapio, Bologna, 1990.

5- Pnueli D., Gutfinger C., Meccanica dei fluidi, Zanichelli, 1995.

6- Barletta A., Applicazioni della fisica termica, Pitagora, Bologna, 2002.

7- Fabbri G., Fluidodinamica applicata - 50 esercizi svolti, Progetto Leonardo, Esculapio, 1999.

8- Esercizi di Fisica Tecnica, Volumi 1-10, Libreria Editoriale Petroni, Bologna.

Teaching methods

Practical lessons are intended to show the applications of theory as well as to give a deeper knowledge of some topics.

Assessment methods

The exam deals with theoretical and practical topics and is divided in two parts: a written test and an oral examination. Typically, the written test is as follows: a theoretical question and a numerical exercise of Applied Thermodynamics, a theoretical question and a numerical exercise of Fluid Dynamics, a theoretical question and a numerical exercise of Heat Transfer. For the written test, the use of a personal calculator is required; however, students are not allowed to consult books and notes.

Office hours

See the website of Stefano Lazzari

See the website of Sandro Salvigni