1. Analyses of the suspended-load sedimentation process and its dynamics in reservoirs with high daily oscillationsHelena Vrecl-Kojc, Bojana Dolinar, Roman Klasinc, Ludvik Trauner, 2008, izvirni znanstveni članek Opis: The river water pumped into reservoirs with high daily oscillations, e.g. at pumping hydroelectric power plants, contains different amounts of suspended load depending on the time period and the riverćs discharge. This paper presents an analysis of the suspended-load sedimentation process that is based on the interaction between the sedimentation, i.e., the settling, velocity and the motion of the water. The settling velocity of spherical particles in the presence of a buoyancy force is a function of the particle size. Laboratory investigations of the suspended material from the river-watersamples have determined the ratio between the particle size and the concentration of suspended material with respect to the river discharge, the ratio between the concentration of suspended material in the water and the discharge, and the relationship between the concentration of suspended material and the discharge of water, which is for the first time expressed as an exponential function. The motion of the water in the reservoirs with high daily oscillations is solved by the three-dimensional modeling of the liquid streams. The evaluation of the results is presented for the case of the planned Kozjak pumping hydroelectric power plant on the River Drava. Ključne besede: suspended load, water motion, sedimentation, sedimentation transport, pumped hydroelectric power plant, reservoir Objavljeno v DKUM: 05.06.2018; Ogledov: 2016; Prenosov: 67
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2. Analysis of concentration and sedimentation of suspended load in the reservoirsHelena Vrecl-Kojc, Bojana Dolinar, Roman Klasinc, Ludvik Trauner, 2008, izvirni znanstveni članek Opis: This paper deals with the sedimentation of suspended load in the reservoirs. As an example the reservoir of the hydroelectric power plant Boštanj on the Sava River is shown. The objective of the described studies was to determine the quantity and type of deposited material in the reservoir during the selected time period. For this purpose, the mineral and chemical composition, and the concentration and the particle size of the suspended load at the intake of the water into the reservoir and at its outflow were examined. In order to determine the concentration of the suspended load, 24 water samples from the area of the intake and outflow from the reservoir were taken. At the same time the discharge of the Sava River was measured. Solid particles were removed from the water with the help of sedimentation and in the final stage of water evaporation. The results of the studies showed that the concentration of the suspended material was changing in relation to the location and the flow rate of the water. This ratio can be described with an exponential function.
In suspended load composition carbonates, muscovite/illite and quartz dominate; however, chlorite was also found, as well as small quantities of plagioclase and organic detritus. With regard to the size of the particles the examined samples are classified as silt.
It was determined that the concentration of the suspended load, at the same flow rate of water, at the intake into the reservoir is larger than at the outflow. The difference is represented by the material that was sedimented in the reservoir due to the decreased speed of the water as a result of the river's impoundment. A comparison of the composition of the samples from both collection sites showed that at the outflow site of the water from the reservoir there is a somewhat smaller share of carbonate grains and heavy minerals than at the intake site, and a higher content of organic detritus and clay particles can also be observed. Considering the actual discharge of water in the period between July 2006 and July 2007 and the examined ratio between the flow rate of the water and the quantity of suspended and deposited material, the total quantity of sedimented material in this period was estimated. Ključne besede: suspended load, sedimentation, sediment transport, water storage reservoir Objavljeno v DKUM: 05.06.2018; Ogledov: 2091; Prenosov: 86
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3. Air-release and solid particles sedimentation process within a hydraulic reservoirVito Tič, Darko Lovrec, 2013, izvirni znanstveni članek Opis: Contaminant in a hydraulic fluid is broadly defined as any substance that impairs the proper functioning of a hydraulic system. Hydraulic fluid can be contaminated by air, particles, water, and foreign fluids. Fluid contamination can cause numerous problems including component damage, unacceptable noise, poor component response and severe fluid degradation. This paper focuses on two major contaminants that should be considered when designing a hydraulic reservoir - air and particle contamination. A proper reservoir design can prevent the occurrence of air and solid contaminants within the hydraulic system and reduce their negative effects. A hydraulic reservoir should be designed in such a way as to stabilize and direct the oil flow inside the reservoir, so that the fluid has enough time to release air bubbles and to deposit solid particles. In order to visualize and understand flow patterns inside the reservoir, all the advantages of using simulation techniques within the field of reservoir design will be shown. This paper investigates the trajectories of solid and gaseous particles within a hydraulic reservoir, which are based on simulated transient phenomena using the Ansys Workbench. The results obtained focus on the sedimentation of solid particles and the elimination of gaseous particles within a hydraulic reservoir. Ključne besede: hydraulic reservoir, air bubbles, solid particles, simulation, trajectories Objavljeno v DKUM: 10.07.2015; Ogledov: 1579; Prenosov: 132
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