ISSN 2343–7707 ; ISSN-L 1453-7303

HIDRAULICA Magazine No. 1 / 2022

Hidraulica no. 1/2022

Experimental Research on a Savonius Helical Turbine with Integrated Transparent PV Cells
Authors: Sanda BUDEA, Ștefan-Mugur SIMIONESCU, Octavian LAMBESCU

Starting from the observation that the hybrid wind-solar systems are perfectly complementary both during a day and during a year, an experimental facility was designed and built, consisting of a Savonius wind turbine with helical blades, covered with thin, transparent film of flexible photovoltaic cells. The experimental results show a power coefficient of 0.265 for the Savonius helical rotor and operation starting from wind velocity of 0.65 m/s. This facility can produce energy from two sources, wind and sun, and even more, it ensures … (read more)

Synchronization of the Travel of Hydraulic Cylinders. Modeling and Simulation

In this paper, the author presents the theoretical research and simulations performed for establishing some variants of hydraulic drive for the units that require two or more cylinders. Two simple and affordable methods that do not entail special expenses are shown comparatively. The solutions can be applied for systems that do not require … (read more)

Examination of Losses in Fire Extinguisher System Operated from Centrifugal Pump
Authors: Rajmund KUTI, Péter HORVÁTH, Flóra HAJDU, Csenge PAPP, Gabriella LÁSZLÓ

Nowadays, the most often used fire extinguisher material for fire extinguishing is still water, whom transportation can be conducted in different fire extinguishing systems to the spot of fire. The quantity of the water mass, which can be extracted of the fire extinguisher system depends on the applied unit, and is influenced by losses that occur during water transportation. It is very important to examine the losses occurring inside the water supply system, since they influence … (read more) 

ARX Models as a Useful Tool to Generate Design Hydrograph with Rainfall
Authors: Maritza ARGANIS, Margarita PRECIADO

ARX-type parametric autoregressive models were used to identify the best fit to precipitation effective data and direct statistical runoff corresponding to a 100 years return period, under assumption that a runoff rain process can be treated as a linear system; this model was validated with data from another rain runoff event corresponding to a 10,000 years return period; the best model obtained was the ARX 1 1 1 type. It consists of … (read more)

Modification of the Cavitation Resistance by Hardening Heat Treatment at 450 °C Followed by Artificial Aging at 180 °C of the Aluminum Alloy 5083 Compared to the State of Cast Semi-Finished Product
Alexandru Nicolae LUCA, Ilare BORDEAȘU, Brândușa GHIBAN, Cristian GHERA,
Dionisie ISTRATE, Daniel-Cătălin STROIȚĂ

The paper presents the results of the experiment of behavior and resistance to vibration cavity erosion, carried out on cast aluminum alloy 5083 heat treated by hardening at 450 °C and maintained for 12 hours at the artificial aging temperature of 180 °C. Following the experiment (read more)

Experimental Research on the Influence of Factors on the Electricity Production of Thin-Film Photovoltaic Panels
Authors: Adriana TOKAR
, Dănuț TOKAR, Filip STOIAN, Daniel MUNTEAN

Given the current context regarding environmental pollution, in which conventional installations also participate, the aim of this article is to analyse whether photovoltaic systems are a viable solution to help solve this problem. Thus, the article analyses the way in which the electricity production of photovoltaic installations is influenced by the aging of the photovoltaic cells that make it up, but also by (read more)

Determining the Relation between the Size of the Air Bubble Immersed in Water and the Dissolved Oxygen Concentration
Authors: Marilena Monica BOLTINESCU (ROZA), Nicolae BĂRAN, Mihaela CONSTANTIN

Starting from the equation of oxygen transfer rate to water, a mathematical connection is established between the concentration of dissolved oxygen in the water and the diameter of the air bubble introduced in … (read more)

Use of a Cylinder with Two Piston Rods
Authors: Cătălin FRĂȚILĂ, Tiberiu AXINTE, Roxana DAMIAN, Elena CURCĂ, Diana DUMITRAȘ

This paper presents aspects related to the use of cylinders with two piston rods. Beside the cylinder with two piston rods, there is also a pneumatic actuator. This actuator is a cylindrical metal machine, which guides with two piston rods in a straight-line, a reciprocating movement in a cylinder. In this article, four circuits for cylinders with two piston rods, both pneumatic and electro-pneumatic circuits are presented. The first pneumatic circuit is a simple one and has only … (read more)

Hydraulic Station for a Railway Track Welding Machine
Authors: Ioan LEPĂDATU, Liliana DUMITRESCU, Ștefan ȘEFU, Laurențiu Valentin NICOLAE,
Dănuț Florin MATEESCU

The welding head of the containerized and completely independent mobile machines for flash-butt welding of train and tram tracks is operated with the help of a hydraulically actuated rotary crane. The article shows a hydraulic station that provides the hydraulic energy needed to … (read more)

Simulations regarding the Modernization of the District Heating System in Timisoara by Controlling the Supply and Regulating the Temperature of the Heating Agent
Authors: Daniel MUNTEAN, Matei MÎRZA, Adriana TOKAR, Dănuț TOKAR

The current context of climate change requires the efficiency of district heating systems. The article proposes the implementation of modernization solutions for district heating systems in order to reduce heat loss on the distribution system and implicitly CO2 emissions at the level of thermal agent production. The case study analyses the supply of the Forestry Technical College from Timisoara, which has a heat demand for the building of 1MW and is located at a distance of 1200m from the nearest thermal point. Simulations were performed for several efficiency stages of … (read more)

Experimental Demonstrations of Extension of Technical Applications for Pumping Units Equipped with Miniboosters
Authors: Teodor Costinel POPESCU, Alexandru-Polifron CHIRIȚĂ, Alina Iolanda POPESCU,
Andrei VLAD, Ionel Daniel VOCHIN, Ana-Maria Carla POPESCU

The authors of this article have developed three high-pressure pumping modules, composed of low-pressure electric pumps, equipped with oscillating hydraulic pressure intensifiers (miniboosters), which they intended to use to supply hydraulic cylinders of small dimensions and high forces. Due to the flow and pressure pulsations that occur at the outlet of the minibooster secondary side, such pumping modules are recommended for applications with static loads, which imply … (read more)

Researches on Water Aeration Using Fine Bubbles Generators
Authors: Marilena Monica BOLTINESCU (ROZA), Nicolae BĂRAN, Albertino Giovani ROZA,

The paper presents the constructive solution of a fine air bubble generator that is used to aerate waters. This generator is provided with a perforated plate, which has orifices for the introduction of air into the water, as follows: … (read more)

Hydraulic Installation for the Rotary Crane of a Railway Track Welding Machine
Authors: Ioan LEPĂDATU, Ștefan ȘEFU, Ionela Mihaela BACIU, Laurențiu Valentin NICOLAE,
Dănuț Florin MATEESCU

A railway track welding machine has several components in its structure, the most important being the welding head, which performs the electric flash-butt (end-to-end) welding of the train and tram tracks. Maneuvering the welding head and positioning it on the rails to be welded is done with the help of … (read more)

Overview of Multi-Position Cylinder
Authors: Tiberiu AXINTE, George SURDU, Alexandru SAVASTRE, Victor BADANAU,
Camelia PASCU, Nilgun MILIS

This paper presents aspects related to the use of a cylinder with two piston rods. Beside a multi-position cylinder, it is a pneumatic actuator. In this article two kind of circuits using a multi-position cylinder are presented: one pneumatic circuit and one electro-pneumatic circuit. The pneumatic circuit comprises … (read more)

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