Andrea's Research

Monika's Research

External Gear Pumps/Motors

Various projects have been performed in the area of external gear units. Purposes of these projects are: the development of accurate simulation models; the proposal of new solutions characterized by better efficiency and lower noise emissions; the development of innovative testing techniques. More details about these project are reported here (Download PDF).

HYGESim

The main result of the research activities in external gear machines is given by the simulation tool HYGESim. HYGESim (HYdraulic GEar machines Simulator) is a numerical model for the simulation of external spur gear pumps and motors. Conceived at University of Parma (Italy) with the support of the company CASAPPA, HYGESim is currently developed at MAHA Fluid Power Research Center.
The simulation tool consists of different modules: a lumped parameter fluid dynamic model, a mechanical model for evaluation of the gears motion (considering also the micro motion of the gear axes of rotation) and a geometrical model. The first two models are implemented within the LMS Imagine.Lab AMESim® simulation environment, with proper submodels written in C language, while the geometrical model is implemented developing proper macros capable to read directly the CAD3D drawings of the unit (pump/motor).
The simulation tool is characterized by an accurate description of the geometry of the different components (i.e. teeth’s profile, design of sliding elements) and it is able to calculate the movements of the gears’ axes of rotation resulting from the forces exerted on both gears. Potentials of the model are represented by the prediction of the main features of flow through the machine (such as the inter-teeth meshing pressure, the evaluation of possible cavitation onsets, pulsation of flow at the external ports, etc.) and the detection of the wear of the casing due to the possible contact between the gears and the casing. The tool is currently used for the analysis of the main phenomena related to the operation of the machine, for the optimization of its design and for the research of innovative solutions.

Gear Ring (Gerotor) Units

In cooperation with Graz University of Technology and with the support of the company MAGNA Powertrain, Maha Fluid Power Research Center has been involved in the development of a computational multi-domain simulation model for Gear Ring Pumps.
The modeling approach consists of a few basic modules which are interacting in different domains. It comprises models for the parametric geometry generation (gear teeth profiles and porting geometry), a lumped parameter fluid dynamic model for the evaluation of the main flow features, a geometric model for the numerical calculation of relevant geometry data (variable chamber area, intersection zones between displacement chambers and inlet/delivery ports), a CFD model for the analysis of the lateral leakage flow. Furthermore, a 3D CAD model integrated to a FEM model is implemented to allow automatic generation of detailed drawings and to permit material deformation/stress analysis. Finally, a model of the hydrodynamic lubricated outer rotor bearing is integrated within the fluid dynamic model.

With the support of MAGNA Powertrain the developed models have been successfully validated with experimental results for different pump designs for both, steady state and transient pump operation.
The developed model permits the analysis of main design parameters on machine performance, in particular as concerns unit’s efficiency, pressure/flow pulsations, leakage flows and torque losses. Different design concepts can be validated with consideration of the respective application (e.g. when working in a complete hydraulic circuit for a specific actuation system).

Gerotor Units - Additional Resources

Download the extended description of the research on Gerotor Units at Maha: GPRs_Research@Maha.pdf (8.5MB)

or stream the video:

Systems/Components Modeling

Various activities have been performed concerning the modeling and testing of hydraulic systems and components (with particular reference to hydraulic valves). Some exemplifying projects are reported here (Download PDF).
Concerning the valve modeling, the described projects show the capability of simulating not only the main phenomena related to the internal flow, but also the interaction between the internal parts (the mechanical elements and the electro-magnetical actuation system, if present) and between the other components present in the considered system. Moreover, the aspect related to the possible control strategies are accounted as well.

In few cases, advanced optimization criteria have been used to improve current designs or to formulate new solutions. All developed models were validated on the basis of experimental measurements. For systems, the considered cases are pertinent to hydrostatic transmissions and to other hydraulic systems for mobile applications. In these cases, lumped parameters models were developed with the aim of analyzing the margin of improvements of current solutions and to design innovative systems.

Fluid Properties Modeling

The research on fluid properties modeling is aimed to find formulations suitable to describe peculiar flow features within hydraulic components, such as the cavitation, the effect of temperature and pressure, and the presence of dissolved or non-dissolved air. The main aim is to develop formulations suitable for fast simulation models, such as lumped parameters models.