Studies and research on the phenomenon of hydrodynamic erosion in river beds

The phenomenon of hydrodynamic erosion affects the riverbeds in which sub-crossings of pipes or bridges are located. The depth of erosion is determined at a point in the riverbed by the use of specialized computational relationships. For some works located in the riverbed it is necessary to know the erosion depths on the perimeter of the flow section. The analysis models used to investigate the phenomenon of hydrodynamic erosion were: a - topographic model; b - calculation relations from the technical regulations; c - erosion simulation model on a river section. The obtained results were materialized by the evolution of the erosion depths on the considered river sector over an interval of about 5-15 years. The depth of erosion on the lower course of the Moldova River showed values from 0.75 m to 1.65 m on a research sector. The research results were capitalized on the design of the rehabilitation works of the constructions present in the riverbed.

Modeling the working media flow in shut-off valves with displacement of the regulating body perpendicular to the flow axis

The mathematical model of the working fluid movement in the flow section of the wedge type two-disc parallel gate valve is developed. The simulation of the fluid flow through the valve cavity is carried out, as a result the flow parameters are obtained in a wide range of Reynolds numbers at the entrance to the calculated area. The dependence of the hydraulic resistance as a function of the Reynolds number for liquid and gas flow is calculated. The various positions of the shut-off body in the flow part of the valve are considered and the area of reduced pressures in which the effect of cavitation may occur during fluid flow is estimated.

Performance Evaluation of a Density Measurement Tool for ESP Applications

Knowledge of fluid densities in oilfield activities is vital during production operations. The information can be used to ascertain changes in the type of produced fluids, determine water cut, gauge equipment performance, etc. This study presents the evaluation of a measurement tool that can be installed with an electric submersible pump (ESP) to measure in-situ fluid densities during production operations. Such tools can also be configured for use in non-ESP applications. The density measurement tool has a 5.62-inch outer diameter, typical of some ESP components, which may be installed in a 7-in, 26 lb/ft casing. The tool consists of two flow sections with a 5-degree deviation angle. Total flow rates from the analysis were varied from 2000 barrels per day (bpd) to 12,000 bpd with water as the operating fluid. Pressure drop data within each flow section of the tool were obtained and the fluid densities determined. The estimated densities were compared with the known densities for water. The results indicate that the pressure drop measurements depend on the entry distance of fluid to the first measurement point within the tool. Other contributing factors include the distance between the measurement sensors and the deviation angle between the flow sections. These factors were optimized by incorporating flow symmetry into and out of the tool to ensure reduced variability of the pressure measurements and thus enable computation of the fluid densities. Overall, incorporating the two flow sections with known deviation angle was beneficial to reduce the complexity of estimating the fluid densities. Therefore, having a simple internal flow architecture in addition to optimized pressure measurement capabilities for each flow section has the potential to estimate fluid densities. Such a tool may be used as a means to measure in-situ and surface fluid densities from flows typical of oilfield production operations. The main benefit is to obtain instantaneous fluid density mesurements for more accurate production monitoring and faster decision-making during production with an ESP. This study presents a tool with a different internal architecture and a method that can be used to estimate fluid densities from flows typical of oilfield production operations. The tool architecture and measurement technique are simple and have the benefit of easy integration into a flow monitoring system. Such systems are of value to oilfield operators and stakeholders to optimize hydrocarbon flow and implement effective production management of field assets.

Development of a Pressure Control System According to Paste Rheology for Ultrasound Processing in Industrial Olive Oil Extraction

Recent research has demonstrated how ultrasound can benefit the industrial processing of olive paste before oil extraction. However, the absence of a device for controlling pressure inside the sonication cell is a major hindrance to its application. To address this problem, a pneumatic device with a programmable logic controller was implemented to automatically adjust pressure in the sonication cell according to a preset value: its functionality was tested in industrial oil extraction. An experiment was conducted to compare device performance when applied to olive batches with different solid/liquid ratios and differing rheology. The control system adjusted the flow section of the valve at the outlet of the sonication cell and the mass flow rate of the feed pump in order to maintain the pressure preset by the operator. Results indicate that the pressure was 3.0 ± 0.2 bar, 3.5 ± 0.2 bar, and 4.0 ± 0.2 bar when the set point was 3.0 bar, 3.5 bar, and 4.0 bar, respectively: there was thus no significant difference between controlled and set values. This indicates that the device is able to control pressure inside the sonication cell with a maximum deviation of 0.2 bar. In this case, the sonication intensity was stabilized at 135 W/cm2, 150 W/cm2, and 165 W/cm2 at 3.0 bar, 3.5 bar, and 4.0 bar, respectively. This study presents an advancement in ultrasound applications for industrial olive oil extraction: optimal pressure control in the sonication cell.

Improving the Efficiency of the Liquid Heater in the Pre-Start Preparation of the Internal Combustion Engin

Introduction. In this article the study subject is the power supply system of the pre-start heater. The purpose of the study is to evaluate the possibility of using a thermoelectric generator to power the liquid preheater with optimization of the flow section of the thermoelectric generator heat exchanger. Materials and Methods. It is proposed to use a thermoelectric generator as an additional energy source to reduce electric power consumption by a pre-start heater. In the course of the study, various structures of the flow section of the thermoelectric generator heat exchanger have been modeled. The thermal and hydrodynamic analyses were carried out in the software environment ANSYS Workbench, Solidworks Flow Simulation to develop the most effective design for the flow section of the thermoelectric generator heat exchanger Results. An experimental installation was assembled and the dependence of the temperature modes of the pre-start heater on the output parameters of the thermoelectric generator was determined. Discussion and Conclusion. It has been proved the possibility of reducing the power consumption of the vehicle battery during thermal preparation of the internal combustion engine by using a thermoelectric generator adapted to the power supply system of the liquid pre-start heater.

Variasi Diameter Nozzle Terhadap Lamanya Proses Vakum Pada Fresh Water Generator di Laboratorium Polimarin

Ejector is a static pump which is worked by a vacuum principal. A vacuum which is happened in the ejector affect the performance and the ability of suction on the secondary mass flow section. A vacuum ejector in the fresh water generator affects the amount of fresh water which is generated. The objective of this research is to know the affection of variation in the outlet diameter of the nozzle towards secondary mass flow, especially on the air suction section (vacuum). In this research, an analysis has been done in a fresh water generator (FWG) with three alternative design of the outlet diameter of the nozzle using Computer Fluid Dynamics (CFD) method to get the optimal performance. The inlet pressure of primary flow is regulated to be steady at 3 bars. The variations of the diameter outlet of the nozzle are 4, 6, and 8 mm. The distance between the edge of the nozzle with outlet flow of the pipe is made at a settled position. The edge of the nozzle is at 3 mm inside the outlet flow of the pipe measured from the inside edge of the pipe. The result of CFD method is shown that on the variation of the outlet diameter of the nozzle 8 mm has the biggest mass flow (4.6838048 kg/s) between 4 and 6 mm. The implication of this research is that the outlet diameter of the nozzle 8 mm has the maximum value of a vacuum.

Numerical modeling of the flow section of shaftless combined pump-electric motor

Одним из значимых принципов для обеспечения гидравлической эффективности проточной части безвального совмещенного насоса-электродвигателя, а также технологичности производства рабочих колес с подобной проточной частью является применение при ее проектировании линейчатых поверхностей. С использованием линейчатых поверхностей построена цифровая модель проточной части, для нее определен эффективный диапазон основных геометрических параметров. На основе принципов построения линейчатых поверхностей и задания критериев гидравлической эффективности разработаны граничные условия, позволяющие проводить натурные испытания на более поздних этапах создания безвального насосного агрегата. С учетом вариативности отдельных геометрических параметров проточной части проведена оценка их влияния на гидравлические характеристики проточной части. Комбинации гидравлических параметров цифровой модели, обеспечивающие максимальную эффективность безвального насосного агрегата, позволяют наиболее точно создавать опытные образцы для натурных испытаний. One of the significant principles for ensuring the hydraulic efficiency of the flow section of a shaftless combined pump-electric motor, as well as the manufacturability of impellers with such flow section is the use of linear surfaces in its design. A digital model of the flow section was developed using linear surfaces, and the effective range of the main geometrical parameters was determined for it. Based on the principles of building linear surfaces and setting hydraulic efficiency criteria, boundary conditions have been developed to allow full-scale tests at later stages of creating a shaftless pumping unit. Taking into account the variability of some geometrical parameters of the flow section, their influence on the hydraulic characteristics of the flow section was evaluated. Combinations of hydraulic parameters of the digital model that ensure maximum efficiency of the shaftless pumping unit allow the most accurate creation of prototypes for subsequent full-scale tests.

Filtering of High Solids Concentration Media Using Complex Powerful to the Flow

Currently, intensification of the filtering processes in media characterized by high concentration of solid particles remains of great interest in many sectors, such as oil production, oil refining, chemical, medical and food industries. One of the reasons that impede filtering could be the high viscosity level of the dispersion medium. It is known that the filtering rate is inversely proportional to viscosity; therefore, filtering of viscous liquids would be carried out much slower. In addition, filtering media characterized by high concentration of solid particles leads to higher costs for creating the process driving force, fast pores fouling in the filtering material and the need for frequent regeneration of the filtering material. Many media characterized by high viscosity, such as mineral oils, polymer solutions and melts, heavily polluted waters tend to reduce the flow section of the porous material channel; and, as a result, hydraulic characteristics are changing and regeneration of the filtering material is hampered. Therefore, replacement of the filtering material is required, which increases the costs. It is possible to intensify the filtering process by ensuring the suspension preliminarily preparing, for example, by increasing the medium temperature or decreasing the suspension viscosity, as well as adding a suitable solvent. In many technological processes such methods are unacceptable. Design, development and study of devices that allow increasing the filtering material service life and reducing energy consumption to create the required pressure gradient while maintaining the device compactness and ensuring the required fineness of filtration still remains a topical task. This paper is proposing to use filtering in combination with cleaning in centrifugal and vibration fields created in hydrodynamic filters. Centrifugal forces field in the hydrodynamic filter is formed due to liquid tangential introduction into the apparatus and rotation of the cylindrical porous filter partition. The method differs from other technologies by creating a potential flow in the apparatus annular zone within the centrifugal forces field. Such flow organization allows purging up to 80% of polluting substances from the media under cleaning by the centrifugal force mechanism; and such substances are removed from the filter without deposition on the filter partition. This would reduce the load on filter material and increase its service life. Vibration of the filtering partition provided for in its structure makes it possible to destroy the sediment layer thereon and to direct the sediment into the filtrate flow. Thus, the proposed hydrodynamic filter is provided with the self-regeneration ability.

Development of vibration system for decreasing of intensity of steel ladle outlet channel tightening

The problem of tightening of outlet channel of steel ladle still remains relevant at present. A review of scientific and technical studies, aimed at elaboration of methods to keep the channel flow section constant presented. An analysis of deposition forming mechanisms on walls of outlet channel of steel ladle was done. To prevent their formation it was proposed to apply a vibration impact on the ladle shutter. Using simulation studies and specially elaborated methodology, the degree of influence and frequency of amplitude oscillations, acting along the ladle channel, on increasing speed of layer thickness formation on its walls and number of tearing off hard particles was established. To evaluate intensity of elastic waves absorption by the refractories of ladle shutter during vibration impact on it, a natural experiment was done. As a result of the experiment an initial information was obtained for determining parameters of oscillation process to guarantee effective functioning of the proposed casting facility. A necessity was established to account tenfold decrease of vibration acceleration during propagation of elastic wave along the casting channel from the lower end of collector nuzzle to the upper end of the ladle casting nozzle. Results of the complex studies became base of technical solution at elaboration of design of the ladle shutter. The elaborated shutter is equipped by a system of exciting vertically-directed oscillations, promoting decreasing intensity of hard particles sticking on the walls of the outlet channel. The design of the perfected ladle shutter and general view of its test model shown, which is equipped with the vertically-directed oscillations exciting system. Depending on capacity of the steel ladles, which can be from 100 to 300 t, their shutters can be equipped with one or several pneumatic plunger vibrators. Each of the plunger having the mass of 0.8 kg, can develop an impact force up to 300 N when supplying into its working cavity compressed air of 0.2 MPa pressure at flow rate 150 l/min. Industrial tests of the modernized shutter in a foundry shop of Yasinovatsky machine-building plant were done.

Numerical Study on the Flow and Heat Transfer Characteristics of a Second Throat Exhaust Diffuser According to Variations in Operating Pressure and Geometric Shape

A numerical study was conducted to investigate the flow and heat transfer characteristics of a supersonic second throat exhaust diffuser for high-altitude simulations. The numerical results were satisfactorily validated by the experimental results. A subscale diffuser using nitrogen was utilized to investigate starting pressure and pressure variation in the diffuser wall. Based on the validated numerical method, the flow and heat transfer characteristics of the diffuser using burnt gas were evaluated by changing operating pressure and geometric shape. During normal diffuser operation without cooling, high-temperature regions of over 3000 K appeared, particularly near the wall and in the diffuser diverging section. After cooling, the flow and pressure distribution characteristics did not differ significantly from those of the adiabatic condition, but the temperature in the subsonic flow section decreased by more than 1000 K. Furthermore, the tendency of the heat flux from the diffuser internal flow to the wall was similar to that of the pressure variations, and it increased with operating pressure. It was confirmed that the heat fluxes of the supersonic and subsonic flows in the diffuser were proportional to the operating pressure to the 0.8 and −1.7 power, respectively. In addition, in the second throat region after separation, the heat flux could be scaled to the Mach number ratio before and after the largest oblique shock wave because the largest shock train affected the heat flux of the diffuser wall.