Advanced modelling of lubricating gaps in positive displacement machines

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Lumped Parameters Model of a Crescent Pump

This paper presents the lumped parameters model of an internal gear crescent pump with relief valve, able to estimate the steady-state flow-pressure characteristic and the pressure ripple. The approach is based on the identification of three variable control volumes regardless of the number of gear teeth. The model has been implemented in the commercial environment LMS Amesim with the development of customized components. Specific attention has been paid to the leakage passageways, some of them affected by the deformation of the cover plate under the action of the delivery pressure. The paper reports the finite element method analysis of the cover for the evaluation of the deflection and the validation through a contactless displacement transducer. Another aspect described in this study is represented by the computational fluid dynamics analysis of the relief valve, whose results have been used for tuning the lumped parameters model. Finally, the validation of the entire model of the pump is presented in terms of steady-state flow rate and of pressure oscillations

Evaluation of Tooth Space Pressure and Incomplete Filling in External Gear Pumps by Means of Three-Dimensional CFD Simulations

The paper presents the computational fluid dynamics simulation of an external gear pump for fluid power applications. The aim of the study is to test the capability of the model to evaluate the pressure in a tooth space for the entire shaft revolution and the minimum inlet pressure for the complete filling. The model takes into account the internal fluid leakages and two different configurations of the thrust plates have been considered. The simulations in different operating conditions have been validated with proper high dynamics transducers measuring the internal pressure in a tooth space for the entire shaft revolution. Steady-state simulations have been also performed in order to detect the fall of the flow rate due to the incomplete filling of the tooth spaces when the inlet pressure is reduced. It has been demonstrated that, despite the need of a compromise for overcoming the limitation of considering fixed positions of the gears’ axes and of the thrust plates, significant results can be obtained, making the CFD approach very suitable for such analyses

Cluster counting algorithms for particle identification at future colliders

Recognition of electron peaks and primary ionization clusters in real data-driven waveform signals is the main goal of research for the usage of the cluster counting technique in particle identification at future colliders. The state-of-the-art open-source algorithms fail in finding the cluster distribution Poisson behavior even in low-noise conditions. In this work, we present cutting-edge algorithms and their performance to search for electron peaks and identify ionization clusters in experimental data using the latest available computing tools and physics knowledge.Comment: 6 pages, 12 figures, Proceedings of: ACAT202

A proposal of a He based Drift Chamber as central tracker for the IDEA detector concept for a future e+e- collider

none10noThe IDEA detector concept for a future e+e− collider adopts an ultra-low mass drift chamber as the central tracking system. It is a He based, 4 m long and 4 m diameter, fully stereo drift chamber with a total material budget of ∼0.016X0 in the barrel part and ∼0.05X0 in the end-caps. It will be instrumented with a readout electronics implementing the Cluster Counting/Timing techniques, allowing for a larger than 3 σ π/κ separation over most of the momentum range of interest.restrictedCuna, Federica; chiarello, gianluigi; Corvaglia, Alessandro; Filippis, Nicola De; Gorini, Edoardo; Grancagnolo, Francesco; Miccoli, Alessandro; Primavera, Margherita; Tassielli, Giovanni Francesco; Ventura, AndreaCuna, Federica; Chiarello, Gianluigi; Corvaglia, Alessandro; Filippis, Nicola De; Gorini, Edoardo; Grancagnolo, Francesco; Miccoli, Alessandro; Primavera, Margherita; Tassielli, Giovanni Francesco; Ventura, Andre

Easy fabrication of aligned PLLA nanofibers-based 2D scaffolds suitable for cell contact guidance studies

An easy, low-cost and fast wet processing-based method named ASB-SANS (Auxiliary Solvent-Based Sublimation-Aided NanoStructuring) has been used to fabricate poly(L-lactic acid) (PLLA) highly ordered and hierarchically organized 2D fibrillar patterns,with fiber widths between 40 and 500 nmand lengths exceeding tens of microns. A clear contact guidance effect of these nanofibrillar scaffolds with respect to HeLa and NIH-3T3 cells growth has been observed, on top of an overall good viability. For NIH-3T3 pronounced elongation of the cells was observed, as well as a remarkable ability of the patterns to guide the extension of pseudopodia. Moreover, SEM imaging revealed filopodia stemming from both sides of the pseudopodia and aligned with the secondary PLLA nanofibrous structures created by the ASB-SANS procedure. These results validate ASB-SANS as a technique capable to provide biocompatible 2D nanofibrillar patterns suitable for studying phenomena of contact guidance (and,more in general, the behavior of cells onto nanofibrous scaffolds), at very lowcosts and in an extremely easy way, accessible to virtually any laboratory