ISSN 2343–7707 ; ISSN-L 1453-7303

HIDRAULICA Magazine No. 1 / 2017

Hidraulica no.1/2017

Determining the Times of Charging and Discharging of Hydro-pneumatic Accumulators

The authors present in this paper some research on the behavior of the hydro-pneumatic accumulators in the hydraulic installations of the machine-tools. They introduce the mathematical models that describe the phases of charging and discharging of these accumulators, taking into account the actual operation of the installation. There are also presented the results of some simulations of installations with accumulators, but also the hydraulic installation with which they checked the mathematical models developed. In this paper, the authors intended to determine the actual time in which the accumulators are able to take over the task of the pumps to supply an oil flow in … (read more)

Modeling of Flow through Cooling Plant with Sea Water
Authors: Mariana PANAITESCU, Fanel-Viorel PANAITESCU, Gabriel TUDOSE

This paper aims at modeling of fluid flow through the installation of sea-water cooling system of an engine. The overall goal is to optimize the flow by modifying driving pipes and decreasing hydraulic losses. It has created a three-dimensional model to reproduce as accurately as the real facility using ANSYS FLUENT 13.0. There were calculated the variation of pressure and flow inside the plant. Flow model chosen is k-ε model. The results are presented graphically. In order to optimize the flow were analyzed the hydraulic losses both analytical and simulation in ANSYS FLUENT 13.0. The differences obtained ranged between 9…15%. For a result as close as possible to reality, the losses of pressure and flow rate variation are measured on  … (read more)

Discreet Flow Distribution in Central Pivot
Authors: Podalyro Amaral de SOUZA, Eber Lopes de MORAES

In the search of a Central Pivot’s best operational performance, the equipment’s electric and mechanical characteristics, plus the realistic knowledge of the hydraulic relationships to which the ”system” as a whole is submitted, is a must for its proper sizing in function of its components adequate choice. The presence of different sprinklers, featuring diverse diameters and hydraulic characteristics, pressure regulators and the possibility of the presence of a larger sprinkler with a booster on the network, allied to the necessity of attending the physical-natural restrictions which wrap-up agriculture production technology, properly express the arduous task of developing irrigation and drainage projects seeking a harmonic arrangement between … (read more)

Some Analyze Considerations of the Kerf Variation for Abrasive Water Jet Cutting of a Steel Material
Authors: Paul A. BASARMAN, Bogdan CIORUŢA

A modern method of cutting materials is considered to be the abrasive water jet (AWJ) cutting method. It is a method that is in full ascension nowadays regarding, especially, the level of usability in production. In order to have the adequate setup for abrasive water jet cutting on a certain system, the surface quality, the kerf aspect, the shape and respectively the form of the obtained part have to be carefully analysed. This paper presents the results obtained after cutting a square shaped part, made of S355 material. In the present study, there were analysed both the inside and the outside of the cut, the kerf width, the aspect of the taper and … (read more)

Design Details and Fluid Flow Analysis for the Centrifugal Pump with Special Rotor Pattern
Author: Fănel Dorel ȘCHEAUA

The operating principle of a pump is represented by the conversion of mechanical energy taken from an energy source such an electric or thermal engine in hydraulic energy of the circulated fluid. By means of a pump, an energy amount is generated being uniformly distributed within the fluid mass that can defeat the hydraulic resistances and reaching a maximum height to which the fluid can be lifted by the pump. The centrifugal pumps are considered as hydrodynamic units that can perform the circulation of a fluid flow rate at a certain height. The primary functional sub-assembly found in the composition of a centrifugal pump is represented by the impeller which through the rotational movement inside the pump body performs the fluid transport from the aspiration region to the pump discharge region. Between the rotor blades and the working fluid some interaction forces are arising due to which the mechanical rotational energy is converted into … (read more)

Experimental Determination of Pressure Losses when the Working Fluid Passes through Hydrostatic Directional Control Valves
Authors: Corneliu CRISTESCU, Cătălin DUMITRESCU, Radu RĂDOI, Alina Iolanda POPESCU

The article makes some general comments on the energy losses from hydrostatic drive system in order to increase their energy efficiency, as well as some theoretical consideration targeting the theoretical possibility of evaluating them, and in the second part of the article there is presented an experimental laboratory research to determine pressure losses when the working fluid passes through a hydraulic directional control valve commonly used in hydrostatic drives. The paper shows the schematic diagram, the experimental stand, as well as some graphical results achieved which, by comparison to the ones in the specialized literature, validate the qualitative and quantitative variation of pressure losses, and also … (read more)

Considerations regarding Aerodynamic Interaction between Two Wind Turbines. Case of Study: Two Wind Turbines with Rotor Diameter of 6 Meters
Authors: Adrian POPA, Beazit ALI, Ionut Cristian SCURTU

In this paperwork are presented results of a study regarding the aerodynamic interactions between two turbines. Each turbine is a 3 blades turbine, with the rotor diameter of 6 meters. This study concludes that the optimum distance between wind turbines should be about … (read more)

Mechatronic Systems Embedded into the Electrohydraulic Control Equipment for Industrial Applications
Authors: Radu RĂDOI, Alexandru HRISTEA, Bogdan TUDOR

Electrohydraulic control equipment manufacturers keep pace with technological evolution and incorporate in these devices the latest technologies. Thus it was switched from analogue technology to digital and from analog control signals to the data communication protocols (e.g. Profibus, CANopen). The latest models of such equipment contain microprocessors and sensors and can be parameterized using software provided by manufacturers. Installation and maintenance of such equipment is recommended to be performed by … (read more)

An Introduction to Hoisting Machines
Authors: Sunny NARAYAN, Aman GUPTA

A mechanical device or apparatus designed for lifting heavy objects or people is known as hoisting equipment. Structurally it is of diverse nature and may be classified based on the construction and application. In this work a brief introduction to these devices … (read more)

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