Positive displacement pumps and motors play a fundamental role in a wide range of engineering applications, including fluid power transmission, lubrication systems, process industries (e.g. food and chemical), and emerging fields such as medical devices and renewable energy systems. Even with the widespread use of electric drives as prime movers, power transmission cannot, in many applications, be achieved solely through electromechanical systems. Fluid power based on positive displacement machines remains a necessary and effective solution. In the current framework of decarbonization and system hybridization, hydraulic technology is attracting renewed interest, both in terms of component optimization and integration with electric machinery, as well as in novel applications such as wave energy converters, wind turbine control systems, and photovoltaic tracking devices. Within this context, the course provides systematic overview of piston, vane, and gear machines for mobile and industrial applications, addressing kinematics, efficiency, steady-state behaviour, and specific design features. It also introduces modelling approaches for pumps and motors, with particular emphasis on state-of-the-art 0D and CFD tools. The course is aimed at providing students with the methodological foundations required to analyse and critically assess the performance of positive displacement machines. Students will develop the ability to select appropriate machine architectures for specific applications, to set up and implement simulation models, and to define and carry out basic experimental measurements for model validation. Real industrial component examples are used throughout the course to connect theoretical concepts with engineering practice. While not exhaustive, the course establishes a solid and coherent foundation for further research and advanced applications in the field.

Awareness of basic concepts covered in Physics and Fluid Mechanics. Additional preparatory material will be provided well in advance to support students from diverse academic backgrounds in achieving a common baseline of knowledge.

Main topics are the following: - Fundamentals of working fluids: liquid properties, dissolved and undissolved gas content, gaseous and vapour cavitation, basic flow equations. - Evaluation of geometric quantities: displacement, kinematic flow ripple, kinematic speed, chamber volume variation, and port plate flow areas. - Displacement control strategies: pressure compensation, load sensing, torque limiting, and electro-hydraulic servo control. - Design features of positive displacement machines: hydrostatic and hydrodynamic slippers, gap compensation and balancing systems, integrated mechanical holding brakes. - Real machine behaviour: working cycle; sources of volumetric losses (leakage, incomplete filling, compressibility effects) and hydro-mechanical losses (pressure- and speed-dependent friction, internal pressure drops); efficiencies and steady-state characteristics. - Fundamentals of lumped parameter modelling: modelling of hydraulic resistances and capacitances, representation of leakage paths, and development of equivalent circuit models of hydraulic machines. - Lumped parameter modelling using Simcenter Amesim: construction and analysis of pump and motor models. - CFD modelling using SimericsMP+: setup of a gerotor pump model, including CAD import, definition of control volumes, Mismatched Grid Interface (MGI), mesh generation, boundary conditions, fluid properties, and post-processing of results. - Laboratory session: dismantling and critical analysis of real components (axial and radial piston machines, vane machines, external and internal gear machines, gerotor and orbital units). - Laboratory session: experimental measurement of steady-state characteristics of a pump or a motor, depending on laboratory availability. Simulations will be performed on students’ personal laptops. AMESim (Student Edition) and Simerics will be installed locally; the former does not require a license, while the latter will be activated via a remote server with a one-month license provided. Installation instructions will be provided in advance.

In presenza

Presentazione orale

P.D.2-2 - Ottobre