ISSN 2343–7707 ; ISSN-L 1453-7303

HIDRAULICA Magazine No. 4 / 2015

Hidraulica no.4/2015

The Calculation of the Pelton and Francis Turbine Hill Chart Using  the HydroHillChart Software 
Authors: Dorian NEDELCU, Adelina GHICAN (BOSTAN)

The paper presents the HydroHillChart software, which is designed to calculate the hill chart for hydraulic turbines (Pelton, Francis and Kaplan) and the operation diagram, based on the energetic primary data that is obtained through turbine model measurements performed on the test rig. The HydroHillChart software is made up of the following four modules: the Pelton, Francis and Kaplan modules – which are used to calculate the turbine model hill chart and the DEX module – which is used to calculate the operation diagram for the industrial turbine prototype. The results of the software consist of graphical curves and numerical results which can be viewed in HydroHillChart and exported as Excel files with a template structure and also … (read more)

Experimental Model of Pneumatic Tracking System  for Photovoltaic Panel
Author: Ionel Laurentiu ALBOTEANU

Because conventional energy production resources are limited, mankind headed for using other sources of energy, alternative, inexhaustible. Solar energy is an alternative to traditional sources. However, the conversion of solar energy into electricity using photovoltaic effect is achieved with low yield (15-18% when using monocrystalline silicon). A method for increasing the yield is based on … (read more)

CFD Study on the Distribution of Fertilizer in the Fertigation Plant
Authors: Petru Marian CÂRLESCU, Oana-Raluca CORDUNEANU, Ioan ȚENU, Gheorghe ȘOVĂIALĂ, Gabriela MATACHE, Sava ANGHEL, Nicolae TĂNĂSESCU

Population growth and the reduction of freshwater resources suitable for agriculture bring forward the use of high performance irrigation systems with minimum water consumption. Drip irrigation is characterized by the distribution of water slowly, dropwise, to the plant roots. Increasing soil fertility in a more intensive agriculture requires judicious application of fertilizers along with irrigation water, called fertirigation process. Drip fertigation installations have proven their effectiveness also in orchards. Studying the distribution of irrigation water has been achieved in the past by analytical and numerical methods; currently, it is based on the known relations of hydrotechnics calculation for pipeline networks operating at atmospheric pressure or overpressure. The study of the distribution of primary solution of fertilization and irrigation water in the final solution for a drip fertigation system has been less well studied in the literature.
In this article, based on mathematical models … (read more)

Wear Properties of Some W/Cu Materials Prepared by Powder Metallurgy
Authors: Claudiu NICOLICESCU, Iulian ȘTEFAN, Victor Horia NICOARĂ, Marius Cătălin CRIVEANU

The aim of the paper is to present experimental research in the field of W/Cu materials processed by Powder Metallurgy (PM) technologies. In order to fabricate W/Cu materials, mechanical alloying (MA) technique was used to obtain nanocomposite powders with the following compositions (85W/Cu, 80W/Cu and 75W/Cu). For the MA process was used a high energy vario planetary ball mill, Pulverisette 4 made by Fritsch and the milling times were between 2 and 8 hours. Green billets were obtained by die pressing at 600 MPa and then … (read more)

Research on Cam Channels for Zoom Riflescopes
Author: Dana GRANCIU

A modern riflescope is a complex device which incorporates some of the latest technologies for processing optical, mechanical and electronic components. Most of mechanical parts are manufactured using CNC technologies. A key optomechanical sub-assembly is the zoom system. In this paper are presented some aspects regarding … (read more)

Researches upon Cavitation Erosion Behavior of Some Stainless Steels with Different Structures
Authors: Lavinia Madalina MICU, Ilare BORDEASU, Mircea Octavian POPOVICIU, Octavian Victor OANCA, Laura Cornelia SALCIANU, Cristian GHERA, Anton IOSIF

The paper is focused on the stainless steel structures and their effect upon the resistance to cavitation erosion. The research was carried out in the Cavitation Laboratory of Timisoara Polytechnic University, on three samples of steel: one with a martensitic structure and the other two samples were duplex steel with structures formed from different proportions of martensite and ferrite (one having 40% martensite and 60% ferrite and the other 76% martensite and 24% ferrite). Those non standard steels were created by SC Prod SRL Bucharest, a company specialized in such matters. The laboratory method used was … (read more)

Multiplexed Delay Compensation and Circular Buffer Method for moving Average Filtering of Signal Acquired from Tactile Sensors in a Mechatronics System for Walking Analysis
Authors: Anghel CONSTANTIN, Constantine DAVID

Traditional filtering performs very well when the frequency content of signal and noise do not overlap. When the noise bandwidth is completely separated from the signal bandwidth, the noise can be decreased easily by means of a linear filter. On the other hand, when the signal and noise bandwidth overlap and the noise amplitude is enough to seriously corrupt the signal, a traditional filter, designed to cancel the noise, besides might introduce signal cancellation or, at least, would result in signal distortion. The paper presents a multiplexed delay compensation and circular buffer method for moving average filtering of signals. The application refers to … (read more)

Effects of Turbo Charging of Spark Ignition Engines
Authors: Aman GUPTA, Sunny NARAYAN

Turbocharging is an important method that is aimed at achieving maximum mechanical efficiency & fuel-economy, both simultaneously in automobiles. The principle objective of turbo charging is to increase the power output per volume and cost of engine. A fact that a turbocharger increases the mass of air in the cylinder and consequently allows more fuels to be burnt, improves the volumetric efficiency of the engine and simultaneously improves engine efficiency by a small but worthwhile amount. Turbochargers are commonly being used on diesel engines for many years. In contrast only a few petrol engines have been turbocharged until recently and it is unlikely that a large fraction of the world petrol engine will be so equipped. There would be a tremendous growth in demand of Gasoline downsizing, in next few years. The present work aims at analyzing the various benefits associated with … (read more)

Validation of a Multiple Linear Regression Model
Authors: Marin RUSĂNESCU, Anca Alexandra PURCĂREA 

In this paper, we present a model of multiple linear regressions for the margin trade. (read more)

Using Load Sensing Control Systems to Increase Energy Efficiency  of Hydrostatic Transmissions
Authors: Corneliu CRISTESCU, Lavinia Madalina MICU, Catalin DUMITRESCU, Petrica KREVEY

This paper makes a pleading reasoning the promotion of devices type “Load sensing” to control the flow and pressure in hydrostatic drive systems, in order to increase their energy efficiency. There are shown the operating principle, typical basic diagrams and some industrial applications. There is also shown a hydraulic diagram developed in INOE 2000-IHP, which is to be tested in … (read more)

Experimental Stand for Diagnosis of Mechano-Hydraulic Continuous Variable Transmission
Authors: Nicolae Florin ROTARU, Liviu Ioan VAIDA

The paper presents an experimental setup able to identify the malfunctions of the dynamic equipment, using spectral analysis of the mechanical vibrations. For this study, it was chosen a continuous variable transmission (CVT) equipped with piezoelectric transmitter which measures the level of vibrations (accelerometer). The acquisition data are then processed to determine the technical conditions and the faults of the machines. The importance of achieving this stand results from … (read more)

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