69156 - Applied Physics

Academic Year 2024/2025

  • Docente: Claudia Naldi
  • Credits: 6
  • SSD: ING-IND/10
  • Language: Italian
  • Moduli: Dario D'Orazio (Modulo MOD 1) Claudia Naldi (Modulo MOD 2)
  • Teaching Mode: Traditional lectures (Modulo MOD 1) Traditional lectures (Modulo MOD 2)
  • Campus: Cesena
  • Corso: First cycle degree programme (L) in Food Technology (cod. 8528)

    Also valid for First cycle degree programme (L) in Viticulture and Enology (cod. 8527)

Learning outcomes

The student will acquire the basic language of Physics and the essential concepts relative to heat transfer and fluid dynamics in food processing. The student will be able to understand and manage the physical parameters that describe foods, to understand the role of the governing parameters that rule the most important thermal and fluid treatments for foods, to understand the physical mechanisms underneath the measuring apparatus employed by food industry and catering sector.

Course contents

Module 1 – Prof. D’Orazio

Introduction to Applied Physics: measurement units, international system, intensive/extensive/specific properties, vector quantities and scalar quantities, defining position, velocity, acceleration, force, pressure, energy and power, phases of matter.

Thermodynamics applied to closed systems: system definition, closed system, open system, isolated system, constituents of a system, property and status, transformation (or process) and cycle, stable equilibrium state, quasi-static process, mutually stable equilibrium, heat reservoir, mechanical apparatus, environment of a system, adiabatic process, the first law of thermodynamics, energy, heat, energy balance, simple systems and internal energy, enthalpy and specific heats. Heat engine, Carnot's theorem, efficiency of a heat engine.

Thermodynamics applied to open systems: fluid element, specific energy of a fluid element, control volume, energy balance for almost simple system in motion in steady state, examples: adiabatic turbine/compressor, heat exchanger, throttling valve.

Simple single-component systems: equation of state, critical point, diagrams (p,T) and (p,v), saturated vapor, ideal gases, Joule's law, adiabatic and isothermal ideal gas processes, Carnot cycle, refrigeration cycle.

Gas mixtures: mole fraction, mass fraction, partial pressure, partial volume. Mixtures of ideal gases: Dalton law. Water vapor-air mixtures (humid air): vapor quality, relative humidity, dew point, psychrometric chart and psychrometer.

Module 2 – Prof. Naldi

Elements of fluid dynamics: fluid element, streamline, steady flow, viscosity, non-Newtonian fluids, internal/external flows, Poiseuille flow, average roughness, Reynolds experiment, hydraulic diameter, laminar regime, turbulent regime, transition regime, concentrated and diffused head losses, Moody diagram, total pressure drop.

Heat transfer: local thermodynamic equilibrium, temperature distribution, heat transfer, conduction, convection, radiation, flow, density of heat flow, thermal power, Fourier law, thermal conductivity. Steady conduction examples: single-layer flat wall, multi-layers flat wall, electrical analogy, thermal resistance for conduction; single-cylindrical layer, multi-cylindrical layers, electrical analogy.

Forced convection, natural convection, mixed convection, heat transfer coefficient, thermal resistance for convection, Nusselt number, Prandtl number, Rayleigh number, internal/external convection. Forced Convection: external flow on a flat plate, internal flow in a circular duct. Natural convection: horizontal/vertical flat plate.

Heat exchangers: double-pipe, shell and tube, cross-flow. Overall heat transfer coefficient. Sizing of a heat exchanger: heat capacity per unit of time, logarithmic mean temperature difference, efficiency of the heat exchanger.

Readings/Bibliography

Lecture notes provided by the teachers available on https://virtuale.unibo.it/ (Italian). The lecture notes contain all the needed theory elements and exercises. You can download the learning material from https://virtuale.unibo.it/ For further information:

Y. A. Çengel, Introduction to Thermodynamics & Heat Transfer, McGraw-Hill

Teaching methods

The course consists of lectures in classroom: both theoretical notions and exercises are presented.

Assessment methods

The notions acquired are assessed by a written test, in which the first part focuses on verifying the knowledge relative to the first part of the course (Module 1) and the second part focuses on verifying the knowledge relative to the second part of the course (Module 2).

The test lasts 120 minutes and is composed of questions designed to check the acquired theoretical knowledge and exercises designed to check the acquired problem-solving knowledge. In particular, both parts of the exam are structured as follows:

- 2 multiple choices theoretical questions where every correct answer is worth 3 points, each incorrect answer is worth -1 point and each answer left blank is worth 0 points;

- 3 open answer theoretical questions where every correct answer is worth 7 points, each incorrect answer is 0 points, each answer left blank is worth 0 points;

- 1 exercise to be solved where a correct answer is worth 8 points, an incorrect answer is 0 points, an answer left blank is worth 0 points.

During the test, the use of a scientific calculator is required, whereas it is not allowed to consult notes, books or other materials.

The two parts of the written test are evaluated separately. The final mark is obtained as the arithmetic average (in case rounded upwards) of the marks obtained in the two parts of the test (the one relative to Module 1 and the one relative to Module 2).

The final mark can be: not sufficient if the total score (average value) is less than 18, or sufficient (with mark between 18 and 30) if the total score is at least 18. If every answer is correct and complete, the mark is 30 cum laude ("30L").

On the website https://virtuale.unibo.it/ students can download examples of tests. Students can consult the list of exam dates on the website https://almaesami.unibo.it/

Once the exam is completed with a satisfying mark, students have to request it to be registered by following the instructions on the website https://virtuale.unibo.it/

Students can do the written test again if the mark does not satisfy them, but every time they take a new exam the previously mark loses any value.

Eligible students (laureandi and students far behind) can email the professors in order obtain an additional scheduled exam during the classes period.

Teaching tools

Slides presented by means of a laptop, explanation of theory contents and exercises. Lecture notes provided by the teachers available on https://virtuale.unibo.it/

Office hours

See the website of Claudia Naldi

See the website of Dario D'Orazio

SDGs

Affordable and clean energy

This teaching activity contributes to the achievement of the Sustainable Development Goals of the UN 2030 Agenda.