Ing Ind - Inf (Mag.)(ord. 270) - BV (469) AERONAUTICAL ENGINEERING - INGEGNERIA AERONAUTICA

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083903 - HEAT TRANSFER AND THERMAL ANALYSIS

Ing Ind - Inf (Mag.)(ord. 270) - BV (470) SPACE ENGINEERING - INGEGNERIA SPAZIALE

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083903 - HEAT TRANSFER AND THERMAL ANALYSIS

Ing Ind - Inf (Mag.)(ord. 270) - BV (478) NUCLEAR ENGINEERING - INGEGNERIA NUCLEARE

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052603 - HEAT TRANSFER AND THERMAL ANALYSIS

Ing Ind - Inf (Mag.)(ord. 270) - BV (479) MANAGEMENT ENGINEERING - INGEGNERIA GESTIONALE

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083903 - HEAT TRANSFER AND THERMAL ANALYSIS

Ing Ind - Inf (Mag.)(ord. 270) - BV (483) MECHANICAL ENGINEERING - INGEGNERIA MECCANICA

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083903 - HEAT TRANSFER AND THERMAL ANALYSIS

Obiettivi dell'insegnamento

The course is aimed at providing both knowledge and know-how for the solution of heat transfer and thermal control problems, with focus on the aeronautics and space fields. An advanced description of conduction, convection and radiation heat transfer modes is provided together with examples of application and the analysis of the devices and methodologies typically used in thermal control systems.

Risultati di apprendimento attesi

The student

- knows the fundamental and advanced concepts about heat transfer by conduction, convection and radiation;

- is able to apply such concepts to properly model simplified and complex systems including external and internal heat transfer for single devices, airplanes and spacecraft;

- can use analytical and numerical tools for thermal design in the fields of aeronautics and space;

- has the competence to understand the open problems and to autonomously stay up-to-date with the technological innovations in such fields.

Argomenti trattati

1. Heat conduction

Fourier law and thermal conductivity. Heat diffusion equation; initial-, boundary- and interface- conditions. Steady-state conduction: one-dimensional solutions in Cartesian, cylindrical and spherical coordinate systems; thermal resistances and equivalent circuits. Transient conduction: lumped parameter method with convection and radiation boundary conditions, also in presence of a heat source; simplified one-dimensional cases.

2. Convective heat transfer

Governing equations, dimensionless version of the thermo-fluid dynamics equations and dimensionless groups of interest for convection. Free and forced convection in external flow: laminar and turbulent boundary layers, micro- and macro- scales, velocity profiles; some relevant heat transfer correlations for different geometries. Forced convection inside ducts: bulk temperature, logarithmic mean temperature difference, fully developed region and Graetz problem; some relevant heat transfer correlations.

Boiling and condensation: vaporization; introduction to capillary and interface phenomena; metastable states; pool boiling, the boiling curve, critical and minimum heat fluxes, factors affecting the boiling curve; introduction to two-phase flow, forced-convection boiling inside tubes; film condensation on vertical flat plates and inside/outside tubes, dropwise condensation.

3. Radiative transfer

Introductory concepts about radiation and interactions between radiation and matter. Thermal radiation, radiation intensity, directional, spectral and total quantities, irradiation and radiosity. Blackbody radiation: Planck distribution, Stefan-Boltzmann law, Wien displacement law, band emission. Emission, absorption, reflection, transmission for real, diffuse and gray emitters; selective surfaces; Kirchhoff law. Radiation exchange between gray surfaces, view factors and their relationships, exchange between gray surfaces in an enclosure. Radiation in gases: emission, absorption, scattering. Solar and environmental radiation.

4. Thermal analysis

4.1 Thermal modeling

Multi-node lumped parameter approach: nodes, networks, resistances. Finite difference and finite volume methods: overview about the methods, mesh types, boundary conditions, discretization schemes and solution strategies, examples of application using commercial or open source software. Ray-tracing/radiosity algorithms and Monte Carlo methods for radiation. Design of heat exchangers and extended surfaces.

4.2 Thermal control

Temperature and heat transfer control. Operating, storage and survival limits. Internal and external exchanges and thermal sources for the different mission/spacecraft types; major issues; modeling and design strategies to implement a thermal control system; description of the most used devices: coatings/clothings/MLI, radiators, first/second surface mirrors, shields, thermal fillers/doublers/washers, cold plates, vapour chambers, heat pipes, heaters, other devices and systems.

Prerequisiti

To profitably follow the lectures the student should have a good knowledge about mathematical analysis (including partial differential equations) and thermodynamics, and at least a basic knowledge about heat transfer and fluid dynamics.

Modalità di valutazione

Exams are scheduled only after the course end (no intermediate test is offered), following the official test sessions scheduled by the School.

The evaluation is performed by means of a written exam consisting of two parts:

- a first part including brief open questions focused on the main concepts of the theory part of the course; these questions are aimed at verifying the learning of the fundamental aspects about the different heat transfer modes and about the methodologies and devices used for thermal analysis and thermal control;

- a second part including

- an open question aimed at verifying the ability to model a heat transfer problem in a way suitable for numerical solution with the finite difference or finite volume methods;

- two exercises aimed at verifying the ability to model and solve a heat transfer problem analytically, making proper simplifications and assumptions if needed, and critically commenting the results. More specifically, in these exercises it is verified the ability to create a conceptual model of a simplified heat transfer problem, to convert it into a system of equations (by using equivalent circuits, energy balances and all the toolbox of analytical results and experimental data/correlations that are described in the theory part of the course) and to solve it and comment the results.

Bibliografia

J.H. Lienhard IV, J.H. Lienhard V, A Heat Transfer Textbook, 4th edition, ISBN: 978-0486479316 Note:

The textbook can be dowloaded from the Web page: http://web.mit.edu/lienhard/www/ahtt.html

T.L. Bergman, A.S. Lavine, F.P. Incropera, D.P. DeWitt, Fundamentals of Heat and Mass Transfer, 7th Edition, Editore: John Wiley & Sons, Anno edizione: 2011, ISBN: 978-0470917855
M. Guilizzoni, La Fisica Tecnica e il rasoio di Ockham - Terza edizione, Editore: Maggioli, Anno edizione: 2017, ISBN: 978-8891624130

Forme didattiche

Tipo Forma Didattica

Ore di attività svolte in aula

(hh:mm)

Ore di studio autonome

(hh:mm)

Lezione

36:00

54:00

Esercitazione

24:00

36:00

Laboratorio Informatico

0:00

0:00

Laboratorio Sperimentale

0:00

0:00

Laboratorio Di Progetto

0:00

0:00

Totale

60:00

90:00

Informazioni in lingua inglese a supporto dell'internazionalizzazione

Insegnamento erogato in lingua
Inglese

Disponibilità di materiale didattico/slides in lingua inglese

Disponibilità di libri di testo/bibliografia in lingua inglese

Possibilità di sostenere l'esame in lingua inglese

Disponibilità di supporto didattico in lingua inglese