# Technical Physics A - L

**Academic Year 2023/2024**- Teacher:

**ROSARIA VOLPE**

## Expected Learning Outcomes

The course aims to equip students with expertise and understanding in the following domains:

- fundamental principles and laws of thermodynamics, with application to system components, thermodynamic and reversed cycles, as well as air conditioning systems;
- three modes of heat transfer and their practical applications, encompassing models for describing and characterizing heat transfer in straightforward geometries and heat exchangers.

## Course Structure

Lessons and exercises are carried out in the classroom using teaching materials and courseware (slides, exercises, etc.) made available to students on the Studium platform at the beginning of and during the course. Should teaching be carried out in mixed mode or remotely, it may be necessary to introduce changes with respect to previous statements, in line with the programme planned and outlined in the syllabus.

## Required Prerequisites

## Attendance of Lessons

## Detailed Course Content

Applied Thermodynamics

1. BASIC CONCEPTS OF THERMODYNAMICS

Classical thermodynamics and energy; heat transfer; International System of Units; thermodynamic system: control mass and control volume; state and equilibrium; state postulate or Gibbs phase rule; zeroth law of thermodynamics; pressure, volume and temperature; transformation and cycles.

2. POINT AND PATH FUNCTIONS

Energy forms: internal, kinetic and potential energy; energy transfer by heat and work.

3. PROPERTIES OF PURE SUBSTANCES

Pure substances and physics of the phase-change processes of pure substances; compressed and saturated liquid; saturated vapour and superheated vapour; property diagrams for phase-change processes. The ideal-gas equation of state and other equations of state; deviation from ideal-gas behaviour.

4. ENERGY ANALYSIS OF CLOSED AND OPEN SYSTEMS AND FIRST LAW OF THERMODYNAMICS

Energy balance for closed systems; moving boundary work; specific heats at constant volume and at constant pressure. Definition of enthalpy. Mass and energy analysis of control volumes. The first law of thermodynamics for closed and open systems. Flow work and energy analysis of steady-flow systems and thermodynamic behaviour of steady-flow engineering devices.

5. THE SECOND LAW OF THERMODYNAMICS AND ENTROPY

Definition of thermal energy reservoirs; heat engines; refrigerators and heat pumps. The second law of thermodynamics: Kelvin-Planck and Clausius statements. Reversible ad irreversible processes. The direct and reversed Carnot cycle. The Carnot principles; the thermodynamic temperature scale. Entropy, isentropic processes and property of diagrams involving entropy. Entropy change of liquids, solids and ideal gases. Entropy balance.

6. TECHNOLOGICAL COMPONENTS

Technological devices; isentropic efficiency of thermodynamic devices; energy, mass and entropy balances for thermodynamic components.

7. GAS POWER CYCLES

The Carnot gas cycle; air-standard assumptions; the Brayton-Joule cycle and deviation of actual gas-turbine cycles from idealized ones; the Brayton-Joule cycle with regeneration; basics of ideal jet-propulsion cycles and other engineering applications; basics of Otto and Diesel cycles.

8. VAPOUR AND COMBINED POWER CYCLES

The Carnot vapour cycle; the Rankine cycle and deviation of actual vapour power cycles from idealized ones; how to increase the efficiency of the Rankine cycle; the ideal reheat Rankine cycle; the ideal regenerative Rankine cycle; cogeneration and combined gas-vapour power cycles.

9. REFRIGERATION CYCLES

The reversed Carnot cycle; refrigerators and heat pump; ideal vapour-compression refrigeration cycle; actual vapour-compression refrigeration cycle.

10. GAS-VAPOUR MIXTURES AND AIR-CONDITIONING

Ideal- and real-gas mixtures and properties; dry and atmospheric air; the psychrometric chart; main air-conditioning processes.

HEAT TRANSFER

11. BASIC CONCEPTS OF HEAT TRANSFER

Heat transfer mechanisms: conduction, convection and radiation. Simultaneous heat transfer mechanisms.

12. HEAT CONDUCTION

The Fourier heat conduction equation; thermal conductivity; solution of steady one-dimensional heat conduction problems; thermal resistance concept and thermal resistance network; thermal contact resistance. Steady heat conduction in plane walls, cylinders ad spheres; multi-layered cylinders and spheres and critical radius of insulation.

13. EXTERNAL AND INTERNAL FORCED CONVECTION AND NATURAL CONVECTION

Classification of fluid flows; non-dimensional parameters for the forced convection; parallel flow over flat planes; flow across cylinders and spheres; flow across tube banks; internal forced convection; laminar and turbulent flows in tubes; physical mechanism of natural convection; equation of motion.

14. THERMAL RADIATION AND RADIATION HEAT TRANSFER

Thermal radiation; blackbody radiation and laws; radiation intensity; radiative properties. Radiation heat transfer; the view factor and relations; black surfaces and diffuse, grey surfaces.

15. HEAT EXCHANGERS

Types of heat exchangers; the overall heat transfer coefficient; the fouling factor; analysis of heat exchangers; the log-mean temperature difference method; the effectiveness-NTU method.

16. MIXED CONDUCTION-CONVECTION PROBLEMS

Heat transfer from finned surfaces; fin equation; fin efficiency and effectiveness. Transient heat conduction and lumped system analysis and Heisler diagram.

## Textbook Information

Y. A. ÇENGEL – Thermodynamics and Heat Transfer, McGraw-Hill

J. MORAN, H.N. SHAPIRO, B.R. MUNSON, D.P. DE WITT – Introduction to Thermal Systems Engineering: Thermodynamics, Fluid Mechanics, and Heat Transfer, McGraw Hill

## Course Planning

Subjects | Text References | |
---|---|---|

1 | Postulato di Stato (Legge di Gibbs) | Y. A. ÇENGEL - TERMODINAMICA E TRASMISSIONE DEL CALORE - MCGRAW-HILL |

2 | Grandezze di Stato e Grandezze di Scambio | Y. A. ÇENGEL - TERMODINAMICA E TRASMISSIONE DEL CALORE - MCGRAW-HILL |

3 | Comportamento termodinamico delle sostanze pure | Materiale didattico - Y. A. ÇENGEL - TERMODINAMICA E TRASMISSIONE DEL CALORE - MCGRAW-HILL-M. J. MORAN, H.N. SHAPIRO, B.R. MUNSON, D.P. DE WITT – ELEMENTI DI FISICA TECNICA PER L’INGEGNERIA - MCGRAW-HILL |

4 | Bilanci di massa ed energia e primo principio della termodinamica | Materiale didattico - Y. A. ÇENGEL - TERMODINAMICA E TRASMISSIONE DEL CALORE - MCGRAW-HILL-M. J. MORAN, H.N. SHAPIRO, B.R. MUNSON, D.P. DE WITT – ELEMENTI DI FISICA TECNICA PER L’INGEGNERIA - MCGRAW-HILL |

5 | Secondo principio della termodinamica ed entropia | Materiale didattico - Y. A. ÇENGEL - TERMODINAMICA E TRASMISSIONE DEL CALORE - MCGRAW-HILL-M. J. MORAN, H.N. SHAPIRO, B.R. MUNSON, D.P. DE WITT – ELEMENTI DI FISICA TECNICA PER L’INGEGNERIA - MCGRAW-HILL |

6 | Comportamento termodinamico dei principali componenti tecnologici | |

7 | Cicli diretti a gas (ad aria standard) e a vapore | |

8 | Cicli inversi a compressione di vapore | |

9 | Psicrometria e trattamenti dell'aria umida | Materiale didattico - Y. A. ÇENGEL - TERMODINAMICA E TRASMISSIONE DEL CALORE - MCGRAW-HILL |

10 | Conduzione stazionaria in geometrie monodimensionali | Materiale didattico - Y. A. ÇENGEL - TERMODINAMICA E TRASMISSIONE DEL CALORE - MCGRAW-HILL |

11 | Convezione forzata esterna ed interna e convezione naturale | |

12 | Scambio termico radiativo | Materiale didattico - Y. A. ÇENGEL - TERMODINAMICA E TRASMISSIONE DEL CALORE - MCGRAW-HILL |

13 | Scambiatori di calore | Materiale didattico - Y. A. ÇENGEL - TERMODINAMICA E TRASMISSIONE DEL CALORE - MCGRAW-HILL |

14 | Problemi misti di conduzione e convezione: la conduzione termica in regime variabile e le superfici alettate | Materiale didattico - Y. A. ÇENGEL - TERMODINAMICA E TRASMISSIONE DEL CALORE - MCGRAW-HILL |

## Learning Assessment

### Learning Assessment Procedures

The evaluation is conducted through both a written and an oral examination. To qualify for the oral examination, students must pass the written test. Both the written and oral examinations assess the student's ability to discuss theoretical aspects of thermodynamics and heat transfer, as well as to solve practical problems and exercises. The written test includes both theoretical questions and exercises to be completed. If circumstances necessitate, the learning assessment can also be conducted online.

If the course was conducted in-person and for all students who attended the course (i.e., with a participation rate of at least 70%), two intermediate tests will be offered: one at the conclusion of the applied thermodynamics section and another at the end of the course. Passing both intermediate tests is equivalent to passing the written exam, and these students will then need to take the oral exam within the academic year. However, intermediate tests will not be offered if lessons are conducted remotely

To guarantee equal opportunities and in compliance with current laws, students enrolled in CInAP can agree with the teacher on any compensatory and/or dispensatory measures, based on educational objectives and specific needs. It is also possible to contact the CInAP reference teacher (Center for Active and Participatory Integration - Services for Disabilities and/or DSA) of the DIEEI (professors Antonella Di Stefano and Arturo Pagano).

### Examples of frequently asked questions and / or exercises

- State postulate

- Real gases: theoretical questions and analytical and/or graphical exercises

- Ideal gases: theoretical questions and analytical and/or graphical exercises through state diagrams

- Saturated mixtures: theoretical questions and analytical and/or graphical exercises through tables and state diagrams

- Incompressible liquid: theoretical questions and analytical exercises through tables

- Heat and work: theoretical questions and analytical and/or graphical exercises

- First Principle balances for closed and open systems: theoretical questions and analytical and/or graphical exercises

- Second Principle balances for closed and open systems: theoretical questions and analytical and/or graphical exercises

- Direct and inverse thermodynamic cycles, gas and steam: theoretical questions and analytical and/or graphical exercises

- Regenerative heat exchanges for performance optimization of thermodynamic cycles: theoretical questions and analytical and/or graphical exercises

- Psychrometry: theoretical questions and analytical and/or graphical exercises

- Stationary conduction in one-dimensional geometries: theoretical questions and analytical and/or graphical exercises

- External and internal forced convection and natural convection: theoretical questions and analytical and/or graphical exercises

- Radiative behaviour of real bodies, the radiative models of the black and grey bodies: theoretical questions and analytical and/or graphical exercises

- Radiative thermal exchanges within cavities consisting of black or grey bodies: theoretical questions and analytical and/or graphical exercises

- Heat exchangers and calculation and sizing methodologies: theoretical questions and analytical and/or graphical exercises

**VERSIONE IN ITALIANO**