scholarly journals Development of an Automated Approach for Updating of the Annual Runoff Module Map

2015 ◽  
Vol 2 ◽  
pp. 35
Author(s):  
N.V. Arefiev ◽  
N.S. Bakanovichus ◽  
A.A. Lyalina ◽  
N.V. Sudakova ◽  
T.S. Ivanov ◽  
...  
Keyword(s):  
Flow Rate ◽  
River Flow ◽  
Flow Characteristics ◽  
Flow Distribution ◽  
Computer Assisted ◽  
Gis Application ◽  
North West ◽  
Hydrological Data ◽  
Hydropower Potential

<p>Several Russian Hydropower Design and Research Institutes have recently fulfilled studies of hydropower potential estimation for NorthWest, Caucasian and Angara River’s regions in Russia. An approach to automate the calculation of river flow characteristics, based on the usage of annual flow rate map, was proposed and tested by the authors for the aims of the studies.</p><p>Annual river flow characteristics together with the terrain data are the most important data sources for evaluation of the hydropower potential.</p><p>A set of requirements was made for the approach and for automation of annual flow rate maps creation in order to provide ability for updates in every 5-10 years.</p><p>A problem of lack of hydrological data for small and medium sized rivers was faced. To determine the hydrological characteristics the Russian code specification "Determination of Design Hydrological Performance" was used for the conditions of the lack of hydrological data, methods of spatial interpolation were also used.</p><p>To solve the problems it is necessary to define the parameters of the annual flow distribution: average annual flow, variation coefficient, coefficient of skewness.</p><p>Mapping is based on the assumption of a smooth change of annual flow rate for any territory in accordance with the distribution of climatic and physiographic factors (topography, soil, groundwater depth, etc.).</p><p>Milestones of flow rate mapping included: preparation of hydrological initial data; creating of the updated flow rate maps; determination of the corrections to the influence of local azonal factors; estimation of the accuracy of flow characteristics calculations.</p><p>In order to update the annual flow rate maps a special GIS application “Hydrologist” was created. The GIS application includes computer-assisted tool for processing the hydrological data, import/export tools, tools for analysis of area zoning data, tools for analysis of annual flow rate values in centroids of drainage-basins, location of water stage gauges, also the old and updated flow rate maps.</p><p>The article deals with the approach description, main problems that were faced and presenting the results.</p><p>The technology has been applied for North-West, Volga and Siberian Federal Districts in Russia. Comparison of the created annual flow rate map with the previously used map shows that the updated map is better of acquiring hydrological data for small and medium sized rivers.</p>

scholarly journals Determination of Flow Characteristics in Technological Processes with Controlled Pressure

2020 ◽  
Vol 11 (3) ◽  
pp. 204-211
Author(s):  
T. Reader ◽  
V. A. Tenenev ◽  
A. A. Chernova
Keyword(s):  
Mathematical Model ◽  
Differential Equations ◽  
Flow Rate ◽  
Gas Flow ◽  
Safety Valve ◽  
Flow Characteristics ◽  
Pressure Change ◽  
Time Curve ◽  
Mass Rate

Assessment of the environmental and economic performance of a safety valve requires information about the flow of the substance through the valve when it is actuated. The goal of this paper was to determine the flow rate of the discharged substance and the mass flow rate of the substance entering the safety valve when it is actuated.Proposed a mathematical model to describe the processes occurring in the valve. The model includes a system of differential equations describing the physical laws of conservation in the internal volume of the valve and differential equations, which link the value of gas flow through the valve with the pressure and the amount of movement of the shut-off disk. Used a modified method by S.K. Godunov to solve gasdynamic equations.Established that the determination of the flow and power characteristics of the valve requires the preliminary construction of a mathematical model of the safety valve operation. Based on this, proposed a method for determining the flow rate of the discharged substance and the mass rate of the substance entering the safety valve when it is actuated.Obtained the flow characteristics of the valves under review and the dynamics of movement of the shutoff disc of the valve, as well as the dependence of the pressure change on the opening time of the valve. Comparison of the calculated values with available experimental data gives good agreement of results (no more than 5.6 % for a gas flow rate, under 10 % for the movement of the valve and change the arrival of gas in time using the standard deviation function of the flow characteristics of 0.6 %), confirms the correctness of the defined mathematical model, used numerical schemes and algorithms, as well as the proposed method and recoverability of the arrival of gas in a pressure–time curve.

scholarly journals Numerical and Experimental Study of Flow Characteristics in Solar Collector Manifolds

Energies ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1431 ◽  
Author(s):  
Panagiotis Karvounis ◽  
Dimitrios Koubogiannis ◽  
Elias Hontzopoulos ◽  
Antonios Hatziapostolou
Keyword(s):  
Flow Rate ◽  
Solar Collector ◽  
Flow Characteristics ◽  
Flow Distribution ◽  
Computational Grids ◽  
Forced Circulation ◽  
Efficient Operation ◽  
Rate Distribution ◽  
Flow Models ◽  
Cfd Method

The flow through a forced circulation Z-type flat plate solar collector was investigated by means of combined experimental measurements and numerical simulations. The efficient operation of such collectors depends on the uniformity of the flow rate distribution among their riser tubes, while low pumping power demand is also sought. Mass flow rate measurements in the riser tubes were performed, utilizing a specially adapted ultrasound instrument for various values of total flow rates in the collector. By means of a commercial Computational Fluid Dynamics (CFD) code, laminar and turbulent flow models in different computational grids were tested and validated against the experiments. Appropriate metrics were introduced to quantify flow rate distribution non-uniformity among the risers, and pressure drop through the manifold was calculated. Parametric studies for flow conditions outside the experimental window were performed utilizing the CFD method in order to assess the effect of the Reynolds number in the flow distribution among the riser tubes. Furthermore, aiming to enhance flow rate uniformity, a methodology based on modifying the diameter of each riser tube was applied and successfully demonstrated. The proposed method can be employed in large solar collector arrays, either as stand-alone systems or as belonging to hybrid alternative sources of energy (ASE) systems, aiming to optimize their overall efficiency.

CFD Simulation of Flow Characteristics in Liquid-Liquid Ejectors

2013 ◽  
Vol 785-786 ◽  
pp. 1164-1167
Author(s):  
Yan Zhang ◽  
Yang Dong Hu ◽  
Lian Ying Wu
Keyword(s):  
Flow Velocity ◽  
Secondary Flow ◽  
Flow Rate ◽  
Cfd Simulation ◽  
Velocity Ratio ◽  
Flow Characteristics ◽  
Flow Distribution ◽  
Mass Rate ◽  
Turbulent Dissipation ◽  
Feed Angle

Computational Fluid Dynamics (CFD) technique was employed to investigate the flow regime and pattern in liquid-liquid ejectors. The results show that the turbulent dissipation rate decreases initially and then increases with the increase of the secondary flow mass rate at a fixed working flow rate, and increases as the working flow mass rate increases at a fixed secondary flow rate. The shape of the flow distribution is convex when the ratio of suction flow velocity to jet flow velocity (velocity ratio) is 0.25,while the shape is concave at the ratio of 4. In addition, the deflection of the flow field inside ejectors is affected by the variation of secondary flow feed angle. There exists an angle of about 24°, at which the flow pattern would be relatively reasonable.

Flow Maldistribution in Multichanneled Microdevices With In-Line Manifolds

2009 ◽  
Author(s):  
J. Soman ◽  
B. Mathew ◽  
T. J. John ◽  
H. Hegab
Keyword(s):  
Fluid Flow ◽  
Microfluidic Device ◽  
Flow Rate ◽  
Flow Characteristics ◽  
Flow Distribution ◽  
Simulation Software ◽  
Channel Width ◽  
Computational Time ◽  
Specific Flow ◽  
The Difference

This paper deals with the analyses of fluid flow distribution in a microfluidic device with in-line manifolds. The analysis was performed using commercially available microfluidic simulation software called CoventorWare™. The number of channels in the microfluidic device considered for this study was kept at ten due to limitations on the number of nodes and computational time. Channels with only square profile were analyzed for flow rates varying between 1 to 60 ml/min. The length of the channels was maintained at 1.5 cm for all simulations. The fluid flow distribution characteristics for different channel widths/depths (200, 100, and 75 μm) were investigated. It was observed that the flow rate decreased from the central channels to the outer channels. The flow per channel was symmetric about the geometric centre of the microdevice. The uniformity in flow was accessed using the root mean square value of flow per channel and it decreased with decrease in channel width/depth for a specific flow rate. The difference in the flow rate through the channels increased with increase in total flow rate. Similarly, the spacing between the channels was varied (300, 200, and 100 μm) for a microdevice with channel width/depth of 100 μm and its corresponding flow characteristics were studied for flow rate ranging between 1 ml/min and 60 ml/min. Finally, the length of each manifold was varied between 2500 μm and 1000 μm for understanding the effect of manifold length on flow distribution. The standard deviation of flow per channel did not show much variation with changes in spacing and manifold length. In addition each design of the manifolds was analyzed on the basis of pressure and flow rate as well as velocity profile in each of the channels.

scholarly journals Methods of assessment hydropower potential of the rivers (the example of Ukrainian Carpathians rivers)

2016 ◽  
pp. 5-12 ◽  
Author(s):  
O. Obodovskyi ◽  
K. Danko ◽  
O. Pochaievets ◽  
Yu. Obodovskyi
Keyword(s):  
Global Climate Change ◽  
River Flow ◽  
Global Climate ◽  
Energy Resources ◽  
Energy Capacity ◽  
Sequence Determination ◽  
Energy Characteristics ◽  
Hydropower Potential ◽  
Alternative Sources

Based on current realities of the massive need of alternative sources of energy and energy-efficiency and energy-saving the algorithm and method of determining hydropower potential of rivers were presented in the article. Approbation of the algorithm and methodology was made on streams Ukrainian Carpathians. The approach of determining hydropower potential by defining its four components was proposed based on the results of approbation. The four components are – total, environmental, technically possible and economically effectively hydropower potentials. This approach provides an estimate of potential energy resources streams, taking into account the potential loss energy capacity, helps prevent these losses and the efficient use of hydropower. Sequence determination of total hydropower potential, as indicative of full theoretical energy characteristics of river flow was justified. Expediency definition and concept of assessing the ecological and particularly technically feasible hydropower potential has been proven. Criteria expert risk of losses technically possible hydropower potential of watercourses was proposed. The scheme of distribution basin hydropower potential has been presented and analyzed in the article. The scheme provides forecasting algorithm changes hydropower, given the prospects of global climate change and fluctuations in water flow as a consequence.

The Numerical Simulation of Flow Characteristics in T-Type Pipe

2012 ◽  
Vol 542-543 ◽  
pp. 1079-1082
Author(s):  
Yu Qin Zhu
Keyword(s):  
Numerical Simulation ◽  
Mass Flow Rate ◽  
Flow Rate ◽  
Heat Exchangers ◽  
Flow Characteristics ◽  
Flow Distribution ◽  
Simulation Software ◽  
Heating Furnaces ◽  
Fluent Simulation ◽  
Distribution Uniformity

The manifolds are flow distribution devices commonly used in the heating furnaces, heat exchangers, reactors, boilers, and so on. The flow distribution uniformity in the manifolds, to a large extent, decides the operation safety and economy of these devices. Manifolds are consisted of a number of T-type pipes, the flow characteristics in the T-type pipe takes an important role in the flow distribution non-uniformity of manifolds, so flow characteristics in T-type pipes were systematically researched and analyzed by the Fluent simulation software in this paper, exploring the influencing factors such as the inlet mass flow rate on flow distribution non-uniformity, and providing some measures to improve the flow distribution uniformity.

scholarly journals The Air Flow Distribution in the Overpressure Sowing Apparatus

2020 ◽  
Vol 14 (1) ◽  
pp. 40-45
Author(s):  
A. Yu. Popov
Keyword(s):  
Flow Velocity ◽  
Flow Rate ◽  
Air Flow ◽  
Flow Distribution ◽  
Volumetric Flow Rate ◽  
Air Velocity ◽  
Air Flow Velocity ◽  
Flow Propagation

To improve the quality of the pneumatic sowing apparatus, it is necessary to study its aerodynamics. (Research purpose) Determination of air flow distribution in the upper part of the seed chamber of the sowing apparatus, taking into account the protrusions of the sowing disk, on which the quality of seeds dosing depends. (Materials and methods) The author chose a sowing apparatus operating at overpressure as an object of research. The author showed that the seed chamber constant sealing in it is provided by the protrusions of the sowing disk, which are made with cut edges on the side of the sowing disk metering element in two planes. The author applied computer simulation of the sowing apparatus. To conduct a numerical experiment, the initial and boundary conditions were determined, and the rotation of the seed disk was taken into account. The calculation of the model was carried out by changing the volumetric air flow in the range of 15-35 liters per second. (Results and discussion) The author constructed isolines of the air velocity distribution at various air flow rates. He determined the values of the air flow in the directions X, Y and Z in the sowing apparatus seed chamber. It was revealed that the largest and the smallest values of this indicator are achieved at 35 and 25 liters per second respectively. It was shown that at an air flow rate in the range of 15-25 liters per second, the distribution of the air flow in the upper part of the seed chamber would be optimal for transporting the seeds with a metering element. The air flow velocity components in Z direction vary in the range from 5.4 to 16.5 meters per second, and in the X and Y directions do not exceed 8 meters per second. (Conclusions) Based on simulation modeling, the author constructed and analyzed graphs of air flow velocity components changes in the three directions of air flow propagation. He determined the nature of the distribution of air flow in the excess seeds discharge area in the design of protrusions with cut corners. He proposed a rational range of air volumetric flow rate of 15-25 liters per second.

Computer-Assisted High-Re Solution TEM

1990 ◽  
Vol 48 (1) ◽  
pp. 162-163
Author(s):  
F.A. Ponce ◽  
H. Hikashi
Keyword(s):  
Signal To Noise Ratio ◽  
Accurate Determination ◽  
Computer Software ◽  
Video Camera ◽  
Image Contrast ◽  
Objective Lens ◽  
Computer Assisted ◽  
Optical Parameters ◽  
Astigmatism Correction

The determination of the atomic positions from HRTEM micrographs is only possible if the optical parameters are known to a certain accuracy, and reliable through-focus series are available to match the experimental images with calculated images of possible atomic models. The main limitation in interpreting images at the atomic level is the knowledge of the optical parameters such as beam alignment, astigmatism correction and defocus value. Under ordinary conditions, the uncertainty in these values is sufficiently large to prevent the accurate determination of the atomic positions. Therefore, in order to achieve the resolution power of the microscope (under 0.2nm) it is necessary to take extraordinary measures. The use of on line computers has been proposed [e.g.: 2-5] and used with certain amount of success.We have built a system that can perform operations in the range of one frame stored and analyzed per second. A schematic diagram of the system is shown in figure 1. A JEOL 4000EX microscope equipped with an external computer interface is directly linked to a SUN-3 computer. All electrical parameters in the microscope can be changed via this interface by the use of a set of commands. The image is received from a video camera. A commercial image processor improves the signal-to-noise ratio by recursively averaging with a time constant, usually set at 0.25 sec. The computer software is based on a multi-window system and is entirely mouse-driven. All operations can be performed by clicking the mouse on the appropiate windows and buttons. This capability leads to extreme friendliness, ease of operation, and high operator speeds. Image analysis can be done in various ways. Here, we have measured the image contrast and used it to optimize certain parameters. The system is designed to have instant access to: (a) x- and y- alignment coils, (b) x- and y- astigmatism correction coils, and (c) objective lens current. The algorithm is shown in figure 2. Figure 3 shows an example taken from a thin CdTe crystal. The image contrast is displayed for changing objective lens current (defocus value). The display is calibrated in angstroms. Images are stored on the disk and are accessible by clicking the data points in the graph. Some of the frame-store images are displayed in Fig. 4.

Perencanaan Sistem Pengurangan Sampah Permukiman Bantaran Sungai Cidurian Kota Bandung

2019 ◽  
Vol 4 (2) ◽  
Author(s):  
Raka Maulana ◽  
Yulianti Pratama ◽  
Lina Apriyanti
Keyword(s):  
Waste Management ◽  
River Basin ◽  
River Flow ◽  
Waste Reduction ◽  
Residential Areas ◽  
Community Based ◽  
Inorganic Waste ◽  
Waste Bank ◽  
The City

<p>Some areas in the city of Bandung is an area that dilitasi by the flow of the river, to prevent the introduction of garbage into the river basin is necessary to note the waste management systems in residential areas along the river. Cidurian river has a length of 24.86 Km along the river flow. Consists of the city of Bandung and Bandung regency. Administrative regions Cidurian River past eight (8) districts, from the region in the District Kiaracondong precisely Village Babakan Babakan Sari and Surabaya populous and the most densely populated. Thus, there should be community-based waste management in the form of a reduction in resources to prevent potential entry of waste into the river basin. Planning waste reduction will be divided into two, namely the reduction of inorganic waste with waste bank then the reduction of organic waste with absorption holes biopori, and bio reactor mini determination of the reduction is determined by the results of the analysis of the sampling covers the composition and garbage, then the result of the measurement characteristics test and analysis results questionnaire.</p>

DETERMINATION OF THE LIMITING FLOW RATE IN LIQUID FILMS FOR HEAT TRAHSFER CRISIS CALCULATION

1978 ◽  
Author(s):  
V. M. Borishansky ◽  
A.A. Andreevsky ◽  
Mikhail Ya. Belenkiy ◽  
G.S Bykov ◽  
Mikhail Gotovskii ◽  
...  
Keyword(s):  
Flow Rate ◽  
Liquid Films
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