1,721,124 research outputs found
Designing hydraulic locking balancing grooves
No full textThe paper deals with the analysis of the influence of the groove axial length, number and position on the total side thrust acting on a spool inserted into a tapered clearance. Adopting a numerical approach based on the Reynolds equation property combined with the continuity equation, the hydraulic locking phenomena are studied for different tapered clearances of practical interest in the presence of different groove configurations. The variation in groove axial length, number and axial position makes it possible to collect important information about the multigrooved spool in a thin film of fluid, including fundamental data for a proper spool design
Analisi Teorico Sperimentale delle Prestazioni di Macchine e Componenti Oleoidraulici
No full textTesi per il conseguimento del Titolo di Dottore di Ricerca in Ingegneria dei Material
Strumenti Numerici per Analisi e Verifica di Valvole Oleodinamiche ad Acqua
No full textLa memoria illustra la metodologia utilizzata per applicare gli strumenti propri della fluidodinamica computazionale all'ottimizzazione funzionale di una valvola oleoidraulica funzionante ad acqua industriale
CAE Development of Automotive Hydraulic Applications
No full textL'articolo illustra i principlai risultati ottenibili mediante l'uso di strumenti numerici a parametri concnetrati e multidimensionali nello sviluppo progettuale e nell'ottimizzazione funzionale di sistemi idraulici per applicazioni automotive
Variable Displacement Axial Piston Pump Volumetric Efficiency Analysis
No full textThis paper describes a study of the volumetric efficiency of a variable displacement axial piston pump. A theoretical model, based on the continuity equation and properly combined with a simplified analytical treatment of leakage flows, is first presented and used to characterise the stationary behaviour of a 9 piston pump for different operating conditions and different configurations. In this study attention is focused on pump volumetric efficiency dependency on overall operational conditions as supply pressure, pump speed, leakage clearance heights, swash plate angle and port plate timing. Successively, a numerical vs. experimental comparison of steady-state pump characteristics is presented; this last part of the paper has been developed with the aim of showing the validity limits of the assumptions made to build up the numerical model. Results confirm the applicability of the simplified hypotheses introduced and validates the analysis of volumetric efficiency previously performed
Influence of Notch Shape and Number of Notches on the Metering Characteristics of Hydraulic Spool Valves
No full textThe paper presents theoretical and experimental results of studies on the influence of shape and number of spool notches on the discharge characteristics (discharge coefficient, velocity coefficient and flow angle) of a hydraulic distributor metering edge. The flow rate vs. pressure drop and the steady state axial flow-force vs. pressure drop diagrams are determined for spools with different configurations of multiple notched metering edges. Various combinations of the shape and number of the notches modulating the metering area of the passage between supply and drain ports were investigated and correlated with flow rate, axial flow force and pressure drop, in order to get estimates of discharge coefficient and flow angle. The procedure is applied to all the data collected during the experimental activity, and shows the behaviour of the flow characteristics in both fully turbulent and transitional region of motion. The influence of notch shape and number on the metering edge flow characteristics is evaluated as well
Distribuzione della pressione nei vani di una pompa a palette
No full textIn questo lavoro sono presentati e discussi i risultati ottenuti da una serie di rilievi sperimentali volti alla misura della pressione nei vani di una pompa a palette di produzione industriale.Le prove, effettuate in diverse condizioni di funzionamento della macchina, evidenziano alcune singolarita' originate probabilmente dal recupero dei giochi da parte delle palette; tali fenomeni si manifestano in prossimita' delle zone di commutazione, laddove la pressione inizia ad aumentare o a diminuire.Vengono inoltre presentati i risultati di un modello di calcolo semplificato, basato sull'applicazione dell'equazione di continuita' ai vani della macchina.Il confronto fra i risultati forniti dal calcolo e quelli sperimentali si mostra incoraggiante nelle sue linee generali, nonostante la semplicita' del modello. Vengono fornite indicazioni per l'ulteriore miglioramento della modellizzazione
An integrated approach to energy recovery from biomass and waste: Anaerobic digestion-gasification-water treatment
No full textThe paper investigates the performance of an integrated system for the energy recovery from biomass and waste based on anaerobic digestion, gasification and water treatment.
In the proposed system, the organic fraction of waste of the digestible biomass is fed into an anaerobic digester, while a part of the combustible fraction of the Municipal Solid Waste is gasified. Thus, the obtained bio-gas and syngas are used as a fuel for running a cogeneration system based on an internal combustion engine to produce electric and thermal power. The waste water produced by the integrated plant is recovered by means of both forward and inverse osmosis.
The different processes as well as the main components of the system are modelled by means of a lumped and distributed parameter approach and the main outputs of the integrated plant such as the electric and thermal power and the amount of purified water are calculated.
Finally, the implementation of the proposed system is evaluated for urban areas with different number of inhabitants and the relating performance is estimated in terms of the main outputs of the system
L'adimensionalizzazione per un migliore uso della CFD in oleodinamica
No full textLa memoria illustra i vantaggi derivanti dall'adozione di strumenti di calcolo fluidodinamico per la progettazione di componenti idraulici di regolazione on-off e proporzional
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