70/0068-M - FLUID MACHINERY AND ENERGY SYSTEMS
Academic Year 2021/2022
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DANIELE COCCO (Tit.)
- Teaching style
- Lingua Insegnamento
|[70/77] CHEMICAL ENGINEERING||[77/00 - Ord. 2017] PERCORSO COMUNE||9||90|
|[70/84] ENERGETIC ENGINEERING||[84/00 - Ord. 2018] PERCORSO COMUNE||6||60|
|[70/89] ELECTRICAL, ELECTRONIC AND COMPUTER ENGINEERING||[89/10 - Ord. 2016] ELETTRICA||6||60|
|[70/89] ELECTRICAL, ELECTRONIC AND COMPUTER ENGINEERING||[89/46 - Ord. 2016] ELETTRICA ON LINE E IN PRESENZA (BLENDED)||6||60|
According to the educational objectives of the Bachelor's Degree in Chemical Engineering, the specific educational objectives of the course are to give the basic knowledge in the field of thermodynamics, fluid machines and energy conversion systems.
The main learning outcomes of the Fluid Machines and Energy Systems course are as follows:
Knowledge and understanding
• Achieve the basic knowledge about the thermodynamic properties of fluids, the mass and energy balances of energy systems and plant components and principles of heat transfer processes.
• Achieve the basic knowledge about the operation of fluid machines.
• Achieve the basic knowledge about the operation and methods used to improve the efficiency of steam power plants , gas turbines and combined cycles .
Applying Knowledge and understanding
• Achieve the ability to perform the energy balance of simple plant components (boiler, condenser , pump , turbine, heat exchanger , etc . ) .
• Achieve the ability to calculate the performance of a prime movers (turbines) or operating machines (pumps, compressors , fans ) .
• Achieve the ability to choose the pump or the fan required by an hydraulic circuit or a ventilation system.
• Achieve the ability to describe the cycle and the operation of steam power plants, gas turbines, combined cycles and combined heat and power systems.
• Achieve the ability to evaluate the main performance (efficiency and net energy production) of a power generation plant or a combined heat and power system.
• Achieve the ability to evaluate the energy production cost of a power generation plant.
• Achieve the ability to find technical and cost data from the equipment suppliers in order to perform a comparative assessment (qualitative and quantitative) between different energy conversion systems in order to find the most effective solution.
• Achieve the ability to describe, represent on thermodynamic diagrams and critically analyze the thermodynamic processes of fluid machines, heat exchangers, boilers and other components used in energy conversion plants.
• Achieve the ability to represent the velocity triangles and outline the shape of the blade for a stage of axial turbomachines;
• Achieve the ability to integrate the knowledge with that of the other courses in order to achieve a general learning in the field of fluid machines and energy conversion systems.
• The course will also allow to consolidate the skills required by the master degree courses as well as for the professional training.
It is required a suitable knowledge of math (algebra, derivative and simple integrals), physics and thermodynamics. Fundamentals of chemistry are also useful.
The formal prerequisites are: Analisi matematica 1, C.I. of Matematica, Fisica 1 and Fisica 2.
The course includes 3 parts.
Part A - Applied Termodynamic
1. First Law of Thermodynamics (6 hours lecture, 4 hours lab). Thermodynamic systems and main thermodynamic properties . The different forms of energy. First law of thermodynamics for closed systems. Internal energy and enthalpy . Specific heats . Conservation of mass . First law of thermodynamics for open systems.
2. Pure substances and gas mixtures (6h lecture, 2 hours lab). TS and HS diagrams and their properties. Phase diagrams PT, PV and PVT. Title of steam, thermodynamic properties in two-phase liquid-vapor equilibrium . Water , TS and HS diagram ( Mollier ) and thermodynamic steam tables. Mass and volume composition of gas mixtures. Volumetric and thermodynamic properties of ideal gas mixtures.
3. Thermodynamic cycles and second law of thermodynamics (6h lecture, 2 hours lab). Thermodynamic cycles . Definition of useful work and cycle efficiency . Main thermodynamic cycles ( Carnot, Otto, Rankine, Stirling, Brayton). The second law of thermodynamics. Reversibility and irreversibility. Kelvin and Clausius formulations of the second law of thermodynamics. Definition of entropy.
4. Fundamentals of Heat Transfer (2 hours lecture, 2 hours lab). Conduction, Fourier's law, thermal conductivity. Convection, Newton's law, natural and forced convection. Convection coefficient. Radiation, the Stefan- Boltzmann’s law. Concept of thermal resistance and overall coefficient of heat transfer.
Part B - Fluid Machines
5. Performance of fluid machinery (6 hours lecture, 3 hours lab). Classification of fluid machines . The compression and expansion processes. Real work, adiabatic, isothermal and polytropic processes. Multi stage compressors and intercooled compressors. Adiabatic, isothermal and polytropic efficiency.
6. Fluid machines (6 hours lecture, 3 hours lab). The concept of a stage of a turbomachine: the stator and the rotor . The Euler equation and the velocity triangles . Nozzles and diffusers. Total enthalpy. the shape of nozzles and diffusers. The flow in rotating machines. The shape of the blades.
7. Operating machines (6h lecture, tutorial 4h). Pumps, compressors and fans. Performance and main construction features. Choice of the operating machine in relation to the circuit. Operating machines in series and in parallel. Pump cavitation . Outline of reciprocating machines.
8. Turbines (2 hours lecture). Classification and performance of turbines. Impulse and reaction turbines. Steam and gas turbines. Hydraulic and wind turbines.
Part C - Energy System
9. Power generation plants (3 hours lecture, 1 hour tutorial). Overall efficiency and specific fuel consumption of a power plant. Utilization factor and electricity producing cost.
10. Steam-power plants (6h lecture, tutorial 4h). Rankine cycle , energy balance and cycle efficiency . Influence of operating parameters on the performance of a steam cycle . Superheating and thermal regeneration. Plant configuration. The main system components: steam generator, condenser, pumps, turbine and heat exchangers . Outline of polluting emissions.
11. Gas turbines (6 hours lecture, 4 hours lab). Brayton cycle, energy balance and cycle efficiency. Maximum useful work and maximum efficiency. Adoption of regeneration in gas turbines. Current technologies of micro gas turbines, aeroderivative and industrial gas turbines. Outline of polluting emissions.
12. Combined cycle power plants (2h lecture, 2 hours lab). The basic scheme of a combined-cycle gas / steam power plant. The energy balance of the heat recovery steam generator. Overall efficiency.
13. Combined heat and power plants ( 1h lecture , 1 hour tutorial). The combined production of electricity and heat . System configurations and performance (efficiency and primary energy saving).
The course has a total duration of 60 hours, 40 hours of lectures and 20 hours of practical exercises. On the basis of the “Manifesto degli Studi” of the University of Cagliari, Lectures will be prevalently held in classrooms, also integrated with
online teaching resources, by using specific online platforms
managed by the University of Cagliari. Lectures will be held even with the use of Power Point presentations and other documents usable online. The practical exercises are solved in the classroom by the teacher and concern the design and the performance evaluation of single components and overall energy systems. For each topic will also be assigned to the students a specific homework which includes practical problems similar to those solved in the classroom by the teacher.
Verification of learning
The final examination includes a written test and an oral examination. The written test, lasting max 2 hours, includes 5-6 practical problems similar to those solved in the classroom. The course includes 2 intermediate written test, the first on Applied Thermodynamics, the second on Fluid Machines. A positive evaluation during the intermediate test will exempt from the final written test.
The oral examination concerns the description of plant schemes, mode of operation and performance evaluation of fluid machines and energy systems.
The presentation of the homework assigned to students during the course and their positive evaluation contributes to the final grade.
The final mark is reported on a 30 basis and depends on the marks of the written test (5%) and oral examination (50%). The positive evaluation of the homework assigned to students during the course can contribute to the final grade with a bonus of 1-2 points.
The mark of the written test is reported on a 30 basis and is the weighted average of the single problems. The weights depend on the complexity and difficulty level of each problem. The rank of 18/30 is assigned for an elementary level of knowledge/ability while the rank of 30/30 is assigned for an excellent level of knowledge/ability.
The following criteria are applied for the evaluation of the written test: a) suitability of the solution process, b) suitability of assumptions, c) Correctness of calculations.
For the evaluation of the homework the following criteria are applied: a) suitability of the solution process, b) Correctness of calculations, c) Effectiveness of ghaphics and discussion of results.
The mark of the oral examination test is reported on a 30 basis. The rank of 18/30 is assigned for an elementary level of knowledge/ability while the rank of 30/30 is assigned for an excellent level of knowledge/ability.
The following criteria are applied for the evaluation of the oral examination: a) Correctness and completeness of answers, b) Analysis of the problem, c) language skills , d) Effectiveness of presentation. Criteria a) and b) are strictly required to pass the examination.
Yunus A. Cengel, “Termodinamica e Trasmissione del Calore”, McGraw-Hill Libri Italia (points 1-4)
V. Dossena, G. Ferrari, P. Gaetani, G. Montenegro, A. Onorati e G. Persico “Macchine a Fluido”, CittàStudi Edizioni (points 5-13).
Other useful books:
Giorgio Cornetti, “Macchine idrauliche” Edizioni il Capitello, Torino (point 7)
Giorgio Cornetti, “Macchine termiche”, Edizioni il Capitello, Torino (points 5, 6 , 8)
Renato Della Volpe, “Macchine”, Liguori Editore (points 9-13)
Renato Della Volpe “Esercizi di Macchine”, Liguori Editore.
All the material presented during the lectures and tutorials, as well as the texts of the exercises proposed to the students, the texts of optional exercises, the written test proposed in previous years, the results of the written tests, the schedule of the oral examinations is available on the website of the teacher and/or on the course Team.