Hydraulic drive systems are widely used in the world of engineering. They often form an essential part of the overall dynamic system in various industries such as metallurgy, energy, aerospace, automotive, etc. This wide range of application requires their continuous improvement. In recent years upgrading of hydraulic drive systems has been clearly oriented towards effective regulation and control which in turn leads to higher levels of energy efficiency. This could be achieved by introducing digital principles and electrical coding in control units realizing pilot electrohydraulic control of relatively larger hydraulic capacity. The following conclusions can be drawn on the grounds of overall analysis of the results obtained by a number of numerical simulation studies which are recorded as separate sections of this paper: 1. Having improved the numerical model concerning dynamic pressure change at different points in the experimental pipeline system, the negative peak pressure is eliminated as the amendment is limited to the range corresponding to the real experiment. Moreover, the results of real and numerical experiment (simulation) overlap very precisely as tolerances in extreme points are less than 0,5%. This correspondence between theoretical and experimental outcomes gives reason to believe that the proposed revised mathematical model is verified thus making it reliable for use in further research of the on-going dynamic processes in long pipelines utilizing digitally controlled three-way two position fast-switching valve. 2. Analysis of the simulation results of transient characteristics of flow rate in the experimental pipeline system show that in terms of digital hydraulic working fluids must feature high coefficient of bulk modulus (1,35 ÷ 1,4.109, Pa) which will result in extended hardness of the hydraulic system and better performance of hydraulic digital control signals. 3. The investigated combination of simultaneously included hydraulic accumulator and counter-balance valve in structural and adjustable parameters shows that it is possible to achieve consistency between the type and format of the input (in control) and output (by pressure) signals, which will lead to high levels of efficiency of regulation in the hydraulic drive system with digital control as well as in other hydraulic systems realized with this method of operation. 4. With amplitude amendment of this size the input digital signal directly affects the width of the output signal (pressure) in the test system. The investigated combination of different amplitude values in the range of 1,0 ÷ 0,1 shows that the width of the output signal relatively changes in the range of 1,0 ÷ 0,75. Taking into consideration the findings of the correlation of the signals in pressure and flow rate, this result shows that it is possible to perform digital control of the actuator device speed. 5. The presented study could be interpreted as a solid ground for further research of hydraulic drive systems with digital control and aims at simultaneous connection of two or more parallel supply valves that are attached to straight pipelines and supply actuator device.
Research analysis of dynamic processes occurring in pipelines with digitally controlled hydraulic valve
2014
12 Seiten, Bilder, Tabellen, 8 Quellen
Aufsatz (Konferenz)
Englisch
Pipeline , Hydroventil , Digitalsteuerung und -regelung , dynamisches Verhalten , hydraulischer Antrieb , Energieeffizienz , elektrohydraulische Steuerung , numerische Simulation , dynamischer Druck , Experiment , Simulation , mathematisches Modell , Dreiwegeventil , Kompressionsmodul , Ausgangssignal
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