20810128-1 - HEAT TRANSFER MODULE I

The course deals with the laws and methods which allow a quantitative evaluation of heat transfer processes (conduction, convection, radiation) between bodies and inside a body, as well as the temperature field variations these processes cause, with the objective of providing the knowledge necessary to design heat transfer devices.
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Programme

Introduction

Units of Measures

1. HEAT TRANSFERS

1) Conduction
phenomenology of heat transfers; general information on thermal fields; Fourier postulated. Fourier's equation, in Cartesian and cylindrical coordinates, with and without internal heat development. Examples of exact solutions: flatbed and cylindrical layer steady. Sull'adduzione limit signs on faces. The similarity of insulating critical elettrica.Raggio. Example variable regime: periodic regime stabilized in a semi-infinite half

2) Convection
Definition. Natural convection and forced convection. Schematic of the phenomenon. Definition of the heat exchange coefficient. dimensional analysis. Buckingham theorem. Method of indexes. Determination of dimensional characteristics of heat transfer variables. Applications.

3) Irradiation
Kirchhoff's law. Planck's law, Stefan-Boltzmann and Wien. gray bodies. Applications.

4) Complex Phenomena
Heat transfer by adduction. Applications.


2. Applied Thermodynamics

1) Thermodynamic systems
Thermodynamics principles. Temperature. thermodynamic equilibrium. Work in a closed system. Temperature concept.

2) First law
Conversion and energy transformation: the formulation of the first principle. internal energy. Specific heat.

3) Second law
Statements of the second law. Carnot cycle. Carnot's theorem. Thermodynamic temperature scale. Entropy. Reversible and irreversible transformation.

4) Thermodynamics Air
gaseous mixtures. moist air. Absolute and relative humidity. dew point temperature. Enthalpy associated. Mollier diagram. moist air transformation. Psychrometer.
energy exchanges between man and environment. thermal comfort. wellness equations. Thermal comfort indices: actual temperature, PMV, PPD.



3. APPLIED ACOUSTICS AND LIGHTING

1) Definition fundamental physical quantities. Characterization of the stimulus.

2) The psychophysical quantities.

3) Applications and Technology about the Sea Engineering : description of the used instrumentation and measurement methodologies, Design principles.



Core Documentation

1. Yunus A. Çengel, “Termodinamica e trasmissione del calore”, McGraw-Hill Education (testo base in versione completa con compendio di Acustica ed Illuminotecnica)
2. Michael Moran et al., “Elementi di Fisica Tecnica per l’Ingegneria”, McGraw-Hill (per consultazione ed approfondimento)
3. Lecture Notes


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Programme

Thermodynamics

Fundamentals: physical quantities and units of measurement, closed and open systems, forms of energy, properties of a thermodynamic system, transformations and thermodynamic cycles, temperature and zero principle of thermodynamics, pressure.
The first law of thermodynamics: the concept of conservation of energy, closed and open systems, enthalpy, energy conservation for stationary flow systems.
Properties of substances: pure substances, heat capacity and specific heats, phases of a substance, phase changes of pure substances, state diagrams, equation of state for ideal gases, transformations.
The second law of thermodynamics: statements of the second law of thermodynamics, heat engines, refrigeration machines and heat pumps, reversible and irreversible transformations, Carnot cycle, entropy.
Thermodynamics of humid air: dry air and atmospheric air, absolute humidity and relative humidity, dew temperature, psychrometric diagram, air conditioning, transformations for air conditioning.

Heat transfer

Steady-state thermal conduction: Fourier postulate, analogy with electrical flow, thermal conductivity, one-dimensional conduction in simple geometries, multilayer flat walls, cylindrical geometries, critical insulation radius.
Forced and natural convection: introduction, dimensionless numbers, classification of fluid motion, limit layer of velocity and temperature, natural convection on surfaces.
Irradiation: introduction, thermal radiation, black body radiation, radiative properties, view factors, heat transmission by radiation between black and gray diffusing surfaces, radiation screens.
Applications: thermal transmittance and conductance of walls, critical insulation radius.

Acoustics

Acoustic quantities: general information, sound pressure and sound pressure level, sound power and sound power level, sound intensity and sound intensity level, psychophysical acoustics, normal audiogram, weighting curves.
Free-field and indoor environment propagation: behavior of materials subjected to sound stresses, sound-absorbing and sound-insulating materials, sound-insulating power, sound insulation, Sabine theory.

Core Documentation

Educational material provided by the Professor

Books:
Yunus A. Çengel, Giuliano Dall'Ò, Luca Sarto, “Fisica tecnica ambientale. Con elementi di acustica e illuminotecnica”, McGraw-Hill Education

Yunus A. Çengel, “Termodinamica e trasmissione del calore”, McGraw-Hill Education

Fabio Polonara, Gianni Cesini, Gianni Latini, “Fisica tecnica”, CittàStudi (only for in-depth analysis)