Learning outcomes of the course unit
The course provides the basic knowledge on the theory of Fluid Machinery, with reference both to single components and to whole plants for power generation. In particular the study will focus on most common actual Power Plants used for energy generation: steam plants, gas turbines, reciprocating internal combustion engines.
Knowledge and understanding:
At the end of the course the student will know the main characteristics of systems for energy generation and the most common power plants used today. He/she will also acquire the knowledge concerning the evaluation of thermodynamic processes, their representation on thermodynamic diagrams, the calculation of the thermodynamic parameters and the amount of heat and work exchanged, both with reference to the ideal and real cases. He/she will then need to know problems, limitations, advantages and disadvantages of fluid machinery and power plants/engines.
Applying knowledge and understanding:
The student will be able to calculate performance parameters of engines and power plants with particular reference to efficiency and specific fuel consumption. He/she will also be able to define the performance of the ideal and real thermodynamic processes that occur in Fluid Machinery and Energy Systems in order to assess in a qualitative and quantitative way thermodynamic states upstream and downstream of machines and components and in different locations of the plant as well as the methods to improve conversion efficiency.
The student will have tools and knowledge needed to critically evaluate and compare different solutions for the realization of specific energy conversion processes (in Fluid Machinery) and power generation (in Engines and Power Plants) starting from main performance parameters usually used to this purpose and taking into account any possible alternatives.
The student must have the necessary tools to effectively present evaluations and comparisons of different solutions for the realization of specific energy conversion processes (in Fluid Machinery) and power generation (in Engines and Power Plants) through both graphs and numerical calculations and representation of thermodynamic cycles giving a clear idea of the key performance parameters usually used to this purpose.
The student will be able, starting from the basic knowledge acquired in the course, to get by himself information and technical data on different Fluid Machinery and Energy Systems that can be studied and/or proposed on the market, thus continuously updating their skills on the solutions proposed and/or applied in the field of conversion processes and energy generation.
Attendance to the course requires knowledge provided by the courses of Math, Physics, Applied Thermodynamics and Fluid Mechanics.
Course contents summary
Energy consumption in Italy and in the world: traditional and renewable energy sources. Energy systems and fluid machinery: characteristics and classification. Internal and external combustion Power Plants. Elements of thermodynamics: 1st and 2nd principle, gases and vapors, thermodynamic diagrams and their use. The Mollier diagram. Applications of the fundamental equations: continuity, energy and momentum. Work evaluation in turbomachinery. Utilization of hydraulic power plants: basin and flowing water schemes. Hydraulic turbines: Pelton, Francis, Kaplan. Energy from fossil fuels: combustion processes and fuel properties. Mass balance, composition of products, air/fuel ratio. Thermodynamic cycles: representation on thermodynamic diagrams, thermodynamic processes, calculation of work and heat exchanges. Ideal, limit and real cycles. The efficiency diagram , specific fuel consumption. Cost of energy, utilization coefficient.
The compressible fluid machinery. De St.Venant equation, compressibility effects and dynamic pressure, Hugoniot equation, Mach number, ideal and real nozzles and diffusers. Mass flow rate in nozzles. Compression and expansion transformations on thermodynamic diagrams, work and efficiency in compressions and expansions. Expansion in an axial turbine stage, rotor enthalpy, degree of reaction, velocity triangles and fundamental kinematic relationship. Operating machinery: typology, main operating characteristics, definition of head.
Steam plants: basic circuit, cycles in saturated steam and superheated steam. Steam generators: types and layouts. Efficiency of the steam generator. Superheaters and economizers. Air preheaters. The condenser and cooling towers. Regeneration and reheat. Thermodynamic cycles on (h,s) and (T,s) diagrams. Performance evaluation for steam plants with simple cycle, with reheat and regeneration. Optimization of steam cycles with reference to specific work and efficiency.
Gas turbines, reference thermodynamic cycles, efficiency and specific work. Air-fuel ratio, combustion chambers. Thermodynamic cycles on (h,s) and (T,s) diagrams. Performance evaluation for simple and regenerated gas cycles. Optimization of gas cycles with reference to specific work and efficiency. The turbine inlet temperature (TIT): effects on efficiency and problems arising from materials strenght. Basics on blade cooling.
Reciprocating internal combustion engines (ICE). Operating principles and basic components. Ideal thermodynamic cycles. Calculation of power output in internal combustion engines. Brake Mean Effective Pressure (bmep). Volumetric efficiency. Combustion processes in spark-ignition and Diesel engines. Air intake and fuel injection in ICE: intake and exhaust systems, valves and actuation systems, ideal and real valve timing and related polar diagram. Fundamental on supercharging and turbocharging.
O.Acton, C.Caputo, Macchine a fluido, vol.1, 'Introduzione allo studio delle Macchine', UTET, 1979.
O.Acton, C.Caputo, Macchine a fluido, vol.2, 'Impianti Motori', UTET, 1992.
O.Acton, Macchine a Fluido, vol.3, "Turbomacchine", UTET, 1990.
G. Ferrari, "Motori a Combustione Interna", Il Capitello, 1990.
C.Caputo, "Gli impianti convertitori di energia", Masson, 1989.
C.Caputo, "Le turbomacchine", Masson, 1989.
Additional material is available via the portal "Web Learning in the University" (lea.unipr.it), where it is available a copy of the slides used during the course.
Lectures will be focused on the study of thermodynamic processes and thermodynamic cycles in Fluid Machinery and Energy Systems and for the calculation of their operational characteristics and performance. The course will be supported by numerical examples and exercises to allow the student to acquire the necessary familiarity with the units of measurement, with the quantitative calculation of ideal and real thermodynamic transformations, as well as with the performance evaluations of the Engines and Power Plants that use primary energy sources.
Assessment methods and criteria
The assessment of learning is accomplished through a written test and oral interview. The first involves the numerical calculation of the characteristics of a thermodynamic process or a thermodynamic cycle and the quantitative evaluation of the main performance parameters: to pass the test numerical results should be correct within the reasonable tolerance due to approximation. The interview is based on theoretical questions and on the application of theory to original problems: in particular the critical capacity, property exposure and the ability to relate the topics covered will be assessed and evaluated.
Attendance to the course lectures and to the presentation of numerical examples is highly recommended.