93035 - FISICA TECNICA 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) - 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

1- A. Cavallini, L. Mattarolo, Termodinamica Applicata, Cleup Editore, Padova, 1992.

2- G. Cesini, G. Latini, F. Polonara, Fisica Tecnica, Città Studi Edizioni. Digital Edition on Pandora Campus.

3- 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 (third ed.).

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.

Teaching tools

Laboratories are organized at the Laboratory of Technical Physics in via Terracini, 34. During the Laboratory, the students learn som experimental techniques for measuring temperature, relative humidity, wind velocity and the calibration of the instruments they use.

Office hours

See the website of Beatrice Pulvirenti