Learning objectives
knowledge and ability to understand
Through the lectures given during the course, the student will acquire the knowledge necessary to understand the operation of fluid machines and internal combustion engines.
Ability to apply knowledge and understanding
Through classroom exercises on some topics, the students learn how to apply the acquired knowledge and the approach to follow in the design of the presented machines.
Evaluation autonomy
The student should be able to understand and evaluate the operation of the studied fluid machines critically, and he should be able to evaluate which machine is most suitable for the application required.
Communication skills
Through the frontal lessons the student acquires the specific vocabulary concerning the fluid machines. It is expected that at the end of the course the student will be able to convey the main contents of the course, such as ideas, engineering issues and related solutions, in oral and written form.
Learning ability
The student who has attended the course will be able to deepen his knowledge through the autonomous consultation of specialized texts, scientific or dissemination journals, even outside lecture topics, in order to effectively address the inclusion in the labour market or undertake further training paths.
Prerequisites
Energy conversion systems (bachelor degree level)
Course unit content
The course aims to provide students with the following knowledge:
the fundamental concepts and the relative equations inherent the motion of compressible and incompressible fluids;
the architecture, the functional and performance characteristics of the main volumetric and dynamic fluid machines;
architecture and main characteristics of boilers;
the functional and performance features of the internal combustion engines for traction.
Full programme
Classification of the power plant. Fundamental equations: continuity equation; energy conservation equation; momentum equation. Euler equation for turbomachinery. Flow forces. Orifice equation. Bulk modulus. Isentropic equations for compressible flow. Hugoniot equation. Flow rate equation for compressible fluid. Chocked flow. De Laval nozzle. Classification of pumps and compressors. Reciprocating compressors, clearance volume, staging, intercooling. Automatic valves. Diagram p-V. Rotary (displacement) compressors, internal and backflow compression; diagram p-V. Reciprocating pumps; diagram p-V; losses through the valves; minimum volume; Gear pumps. Axial piston pumps. pressure ripples and dampers. Dimensional analysis, similitude. Centrifugal pumps, theoretical and actual characteristics. Vaneless Diffuser and vaned diffuser. Radial thrust, multistage pumps, cavitation, priming; series and parallel. Radial flow compressors: velocity diagrams; thermodynamic of the compressor stage; stage loss; vaneless Diffuser and vaned diffuser; operating field. Axial flow compressors: velocity diagrams; reaction ratio; thermodynamic of the compressor stage; stage loss; stall; surge; operating field; choking. Free leaks pumps. Ejector. Boiler and Steam generator: classification and types; efficiency; combustion temperature; water circulation; draught. Hydro-power plants: conventional (dammed water); run of river plant; pump storage plant. Types of hydraulic turbines. Combustion process: high temperature dissociation; flame structure. Gas Turbine: combustion chamber. Gas turbine for aircraft propulsion. Internal combustion engines for automotive applications: p-V diagram; volumetric efficiency; mean effective pressure; combustion process in compression ignition engine; combustion process in spark ignition engine; injection system for diesel and gasoline engines; energy balance; mechanical charging and turbocharging; radial turbine for turbocharging applications. Engine map and automotive applications. Pollutant emissions and aftertreatment systems. Numerical applications: application of fundamental equations for compressible flow; pump characteristic curves; fan maps. Preliminary design: Pelton turbine; centrifugal pump; reciprocating compressor.
Bibliography
All the material presented during the lectures and exercises is made available to students on the Elly platform.
Students are invited to consult the following textbooks:
Dossena, Ferrari, Gaetani, et al. - Macchine a Fluido - Città Studi Edizioni
Ferrari-Motori a combustione interna - Il Capitello
Teaching methods
The course has 9 CFU which correspond to 72 hours of lectures. The teaching activities will be conducted through lectures.
During the lectures the course topics are dealt with from the theoretical-design point of view in order to deepen understanding of the themes by the students.
Some seminars will be held by designers from manufacturers.
The exercises are designed to present some examples of machine sizing.
The slides used to support the lessons will be uploaded on the Elly platform.
To download the slides the students have to enroll in the online course.
Slides are considered an integral part of teaching material.
The two recommended books are very useful teaching material.
Assessment methods and criteria
The exam consists of two written tests. The oral test should be compulsory or optional.
Written test A (weight 0.7)
The first test focuses on the contents presented during the course to check knowledge and comprehension. Two open questions and 5 quizzes (time available 80-90 minutes).
Written test B (weight 0.3)
This test is based on a numerical exercise on one of the topics covered during the classroom exercises (time available 60-90 minutes).
The first and second test are carried out in sequence.
Oral test (if required)
The oral test covers a topic developed during the theoretical lessons and exercises (20-30 minutes dedicated time).
Passing the exam
The final grade is the weighted average of the rating taken in the two tests.
If one of the two written tests has a mark lower than 18/30 the exam is insufficient and must be repeated in full.
The condition for passing the exam without the obligation to take the oral exam is to achieve an average grade of at least 20/30 in the two written tests. Oral is compulsory if the average grade in the two written tests is between 18 and 19.
Oral is required to reach the final vote of 30/30 praise even if obtained the maximum in both written tests; only in the case of a 30/30 praise vote in both tests the final grade is 30/30 praise without oral test.
In the case of the oral exam (compulsorily or optionally) the final grade is the arithmetic average of the grades taken in the oral test and in the written test, this latter calculated with the weight indicated. The oral test covers all the topics presented during the lectures.
Mid-term tests
In order to allow students a gradual preparation of the topics covered in the course, students are given the possibility to take a first mid-term exam and a second test at the end of the lectures.
The mid-term exams are structured both as type A and B written test. An important difference respect to the scheduled exams is the possibility to consult notes for solving the type B test.
To pass the exam, the criteria already stated are valid with the following exceptions:
1. it is possible to pass the exam with an average grade of 18-19/30;
2. it is possible to reach the praise with at least a grade of 30/30 praise in one of the tests and 30/30 in all the others;
3. it is possible to take the oral exam, for the improvement of the grade, in the three appeals of the first exam session after the end of the course. From the second session after the closing of the course the intermediate tests are no longer considered valid neither for the purpose of verbalization nor for the purpose of grade improvement with the oral exam. The oral test covers all the topics presented during the lectures.
Other information
Lecture attendances are highly recommended. Mid-term tests are recommended.
2030 agenda goals for sustainable development
7, 9
