# Heat Transfer and Thermal Analysis

Synthetic program:

il corso fornisce le conoscenze specifiche e gli strumenti operativi per affrontare problemi di scambio termico di media complessità nel campo della propulsione e del controllo termico di componenti e sistemi di interesse aeronautico e spaziale. Per la soluzione di problemi realistici di raffreddamento verrà introdotto l'uso di software specifici.

1. Heat conduction
Fourier law and thermal conductivity. Heat diffusion equation; initial conditions, boundary conditions 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.

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.

## Lecture Notes

### Complete course:

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### Divided by topic:

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### Other:

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## Exercises

### Complete course:

Type File name Year
Digital notes Collection of exercises 2014/2015
Digital notes Collection of exercises 2013/2014

### Divided by topic:

Type File name Year
Digital notes Conduction 2018/2019
Digital notes Convection 2018/2019

### Other:

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## Exams

### First partial exam:

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### Second partial exam:

Type Date
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### Full exam:

Type Date
Text and solution 09/07/2024
Text and solution 11/06/2024
Text and solution 05/02/2024
Text and solution 17/01/2024
Text and solution 08/09/2023
Text and solution 10/07/2023
Text and solution 14/06/2023
Text and solution 14/06/2023
Text and solution 02/02/2023
Text and solution 10/01/2023
Text and solution 05/09/2022
Text and solution 08/07/2022
Text and solution 13/06/2022
Text 04/02/2022
Text and solution 07/02/2020
Text and solution 17/01/2020
Text and solution 10/09/2019
Text and solution 12/07/2019
Text and solution 21/06/2019
Text and solution 07/02/2019
Text and solution 17/01/2019
Text and solution 11/09/2018
Text and solution 11/07/2018
Text and solution 18/06/2018
Text and solution 16/02/2018
Text and solution 16/01/2018
Text and solution 07/09/2017
Text and solution 19/07/2017
Text and solution 05/07/2017
Text and solution 06/02/2017
Text and solution 21/09/2016
Text and solution 07/09/2016
Text and solution 18/07/2016
Text and solution 05/07/2016
Text 03/02/2016
Text and solution 28/09/2015
Text and solution 14/09/2015
Text 11/02/2015
Text and solution 22/07/2014
Text 11/07/2014
Text and solution 10/07/2014

### Oral exam:

Type Date
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### Multiple choice test:

Type Date
Text 14/01/2022
Solution 14/01/2022
Text 26/08/2021
Solution 26/08/2021
Solution 22/07/2021
Text 22/07/2021
Text 02/07/2021
Solution 02/07/2021

### Other:

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## Other

### Laboratory:

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### Projects:

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### Presentations:

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### Collections of notes, exercises or exams:

File name Year
Raccolta domande teoriche

### Etc:

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Esempio parte a crocette

## Live

Quick daily notes, exercises and audio recordings. Files will be approved on priority but deleted after 365 days. 2 points will be assigned by default.

### Quick contents:

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