scholarly journals Increasing the Dosing Accuracy of Magnetodynamic Foundry Equipment

2021 ◽  
Vol 17 (5) ◽  
pp. 42-49
Author(s):  
Oleksii Smirnov ◽  
Anatoliy Narivskiy ◽  
Yevgen Smyrnov ◽  
Anastasiia Semenko ◽  
Aleksei Verzilov
Keyword(s):  
Mass Flow ◽  
Supply Voltage ◽  
Experimental Studies ◽  
Flow Characteristics ◽  
Physical Modelling ◽  
Technical Solution ◽  
Consumption Ratio ◽  
Dosing Error ◽  
Almost All ◽  
Dosing Accuracy

Introduction. The problem of combining continuous monitoring of the main informative process parameters (mass, temperature, melt consumption) and control of the pouring process is relevant for almost all filling devices today.Problem Statement. The development of pouring accuracy methods, particularly for small-dose pouring is an important task for the foundry industry.Purpose. The purpose is to study the dependences of the flow characteristics of the magnetodynamic equipment on the supplied voltage in various conditions of its operation.Materials and Methods. Physical modelling has been applied for the study of dosing accuracy for small doses in the range of 1.5—3 kg.Results. The coefficient of the numerical dependence of instantaneous mass flow consumption of a modeling fluid in the trough on the instantaneous mass of a modeling fluid in the trough has been established based on experimental studies with the use of a physical model of magnetodynamic device (MDD). The studies of filling doses within the range from 1.5 to 3 kg have shown that this coefficient corresponds to the range of the electromagnet supply voltage from 12.3 to 16.3 V. There have been determined the efficient range of the poured-metalmass to instantaneous-mass-flow-consumption ratio in the course of casting (2.20—2.25) and the corresponding range of the MDD electromagnet supply voltage to minimize the effect of jet pulsations on the dosing accuracy byreducing their amplitude. The dosing error does not exceed 1.5% by dose weight in the case of pouring small portions (1.5—3 kg).Conclusions. A new technical solution for MDD with an inclined weighting trough of a conventional design has been developed based on the electromagnetic transfer of a force proportional to the instantaneous melt massin the trough. The implementation of this solution makes it possible to reduce the number of strain gauge power sensors for the instantaneous measurement of the melt mass, from four sensors installed under the melting pot of the MDD prototype to one placed directly under the trough.

Experimental studies on cool-down and mass flow characteristics of a demountable liquid nitrogen transfer line

Cryogenics ◽  
1996 ◽  
Vol 36 (6) ◽  
pp. 435-441 ◽  
Author(s):  
M.V. Krishnamurthy ◽  
Rajneesh Chandra ◽  
S. Jacob ◽  
S. Kasthurirengan ◽  
R. Karunanithi
Keyword(s):  
Liquid Nitrogen ◽  
Mass Flow ◽  
Experimental Studies ◽  
Flow Characteristics ◽  
Nitrogen Transfer ◽  
Transfer Line

Quantitative Experimental Study of SiO2-Water Nanofluids on Backward-Facing Step Flow under Low Reynolds Number

2018 ◽  
Vol 916 ◽  
pp. 221-225
Author(s):  
Ji Zu Lv ◽  
Liang Yu Li ◽  
Cheng Zhi Hu ◽  
Min Li Bai ◽  
Sheng Nan Chang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Reynolds Number ◽  
Volume Fraction ◽  
Pure Water ◽  
Experimental Studies ◽  
Flow Characteristics ◽  
Thermal Engineering ◽  
Heat Transfer Medium ◽  
Step Flow

Nanofluids is an innovative study of nanotechnology applied to the traditional field of thermal engineering. It refers to the metal or non-metallic nanopowder was dispersed into water, alcohol, oil and other traditional heat transfer medium, to prepared as a new heat transfer medium with high thermal conductivity. The role of nanofluids in strengthening heat transfer has been confirmed by a large number of experimental studies. Its heat transfer mechanism is mainly divided into two aspects. On the one hand, the addition of nanoparticles enhances the thermal conductivity. On the other hand, due to the interaction between the nanoparticles and base fluid causing the changes in the flow characteristics, which is also the main factor affecting the heat transfer of nanofluids. Therefore, a intensive study on the flow characteristics of nanofluids will make the study of heat transfer more meaningful. In this experiment, the flow characteristics of SiO2-water nanofluids in two-dimensional backward step flow are quantitatively studied by PIV. The results show that under the same Reynolds number, the turbulence of nanofluids is larger than that of pure water. With the increase of nanofluids volume fraction, the flow characteristics are constantly changing. The quantitative analysis proved that the nanofluids disturbance was enhanced compared with the base liquid, which resulting in the heat transfer enhancement.

The Study of Fire-extinguishing Process of Modelled Fire Seats

2021 ◽  
pp. 57-62
Author(s):  
V.N. Bordakov ◽  
Keyword(s):  
Flow Rate ◽  
Experimental Studies ◽  
Physical Modelling ◽  
Specific Flow Rate ◽  
Specific Flow ◽  
Acceptable Error ◽  
Fire Extinguishing ◽  
Fire Zone ◽  
Analysis Of Results ◽  
Fire Extinguishers

Test-fires to determine fire-extinguishers’ efficiency for extinguishing B class fires are conducted by operators equipped with working clothes, which does not comply with the requirements of physical modelling. This is why the ranks of extinguished modelled seats are significantly overestimated. The quantitative results of fire seats’ extinguishing can be comparatively evaluated in accordance with the value of specific flow rate of a fire-extinguishing agent. As it was detected, the specific flow rate of a fire-extinguishing agent does not actually depend on the rank of modelled fire seat when extinguished by an operator wearing thermal-protective clothes. At the same time, it is increasing along with the expansion of the fire zone scale in case the fire is extinguished without special protective clothes. Consequently, to increase the fire-extinguisher’s efficiency data reliability, the certifying tests should be conducted in conditions close to the real application conditions when the first person to firefight is not equipped with such special protective clothes. The experimental studies to determine the specific flow rate of a fire-extinguishing agent used modelled fire seats of various ranks. The analysis of results showed that the fire-extinguishers ensuring generation of drops of prevailing size more than 0,5 mm are required to extinguish the modelled sire seats. The degree of increasing flow rate for the fire-extinguishing agent to eliminate a fire and observation of a safe distance from the flame for an operator are conditioned by the scale of fire zone and affect the specific flow rate of agent required to ensure stable fire-extinguishing. Based on the results of extinguishing the fire seats «34В» or «55В», it is demonstrated that via using a correction factor it is possible, assuming an acceptable error, to evaluate the flow rate of fire-extinguishing agent to extinguish a modelled fire seat of any rank.

scholarly journals Development of Hybrid Airlift-Jet Pump with Its Performance Analysis

2018 ◽  
Vol 8 (9) ◽  
pp. 1413 ◽  
Author(s):  
Dan Yao ◽  
Kwongi Lee ◽  
Minho Ha ◽  
Cheolung Cheong ◽  
Inhiug Lee
Keyword(s):  
Boundary Conditions ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Stokes Equations ◽  
Flow Characteristics ◽  
Operating Conditions ◽  
Navier Stokes ◽  
Jet Pump ◽  
Two Phase

A new pump, called the hybrid airlift-jet pump, is developed by reinforcing the advantages and minimizing the demerits of airlift and jet pumps. First, a basic design of the hybrid airlift-jet pump is schematically presented. Subsequently, its performance characteristics are numerically investigated by varying the operating conditions of the airlift and jet parts in the hybrid pump. The compressible unsteady Reynolds-averaged Navier-Stokes equations, combined with the homogeneous mixture model for multiphase flow, are used as the governing equations for the two-phase flow in the hybrid pump. The pressure-based methods combined with the Pressure-Implicit with Splitting of Operators (PISO) algorithm are used as the computational fluid dynamics techniques. The validity of the present numerical methods is confirmed by comparing the predicted mass flow rate with the measured ones. In total, 18 simulation cases that are designed to represent the various operating conditions of the hybrid pump are investigated: eight of these cases belong to the operating conditions of only the jet part with different air and water inlet boundary conditions, and the remaining ten cases belong to the operating conditions of both the airlift and jet parts with different air and water inlet boundary conditions. The mass flow rate and the efficiency are compared for each case. For further investigation into the detailed flow characteristics, the pressure and velocity distributions of the mixture in a primary pipe are compared. Furthermore, a periodic fluctuation of the water flow in the mass flow rate is found and analyzed. Our results show that the performance of the jet or airlift pump can be enhanced by combining the operating principles of two pumps into the hybrid airlift-jet pump, newly proposed in the present study.

scholarly journals Determination of mass flow characteristics of supersonic axisymmetric nozzle diaphragms in modeling variable duties of low-consumption turbines

2020 ◽  
pp. 39-43
Author(s):  
Р.Р. Симашов ◽  
С.В. Чехранов
Keyword(s):  
Mass Flow ◽  
Flow Rate ◽  
Flow Characteristics ◽  
Relative Length ◽  
Axisymmetric Nozzle ◽  
Relative Flow Rate ◽  
Wide Range ◽  
Mass Flow Rates ◽  
Subsonic Part ◽  
Low Consumption

В работе приводятся обобщающие зависимости коэффициентов расхода сопловых аппаратов со сверхзвуковыми осесимметричными соплами в широком диапазоне изменения определяющих геометрических и режимных параметров. Предложена двухпараметрическая функция, учитывающая влияние расположения сопел в сопловом аппарате и степени конфузорности дозвуковой части осесимметричного сопла на коэффициент расхода. Показано слабое влияние на коэффициент расхода относительного радиуса закругления стенки в узкой части сопла и относительной длины дозвуковой части сопла в области их оптимальных значений определенных по минимуму потерь кинетической энергии. Переменные режимы работы сопла учитываются зависимостью относительного коэффициента расхода в функции от числа Рейнольдса в критическом сечении сопла. Полученные в работе эмпирические зависимости позволяют использовать их при моделировании переменных режимов и многорежимной оптимизации малорасходных турбин. The research presents generalizing dependences of mass flow rates in supersonic axisymmetric nozzle diaphragms n a wide range of variation of the governing geometric and operating parameters. A two-parameter function is proposed that takes into account the influence of the location of the nozzles in the nozzle apparatus and the degree of compression of the flow of the subsonic part of the nozzle on the mass flow rate. It is shown that the relative radius of rounding of the nozzle wall in the vicinity of the throat section and the relative length of the subsonic part of the nozzle in the region of their optimal values determined by the minimum of kinetic energy losses have a weak effect on the flow rate. Variable duties of nozzle operation are taken into account by the dependence of the relative flow rate as a function of the Reynolds number in the throat of the nozzle. The empirical dependencies obtained in this work make it possible to use them in modeling variable modes and multi-mode optimization of low-consumption turbines.

scholarly journals Gaseous neurotransmitter nitric oxide: Its role in experimental models of epilepsy

2012 ◽  
Vol 64 (3) ◽  
pp. 1207-1216 ◽  
Author(s):  
D. Hrncic ◽  
Aleksandra Rasic-Markovic ◽  
Jelica Bjekic-Macut ◽  
Veselinka Susic ◽  
D. Mladenovic ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Experimental Studies ◽  
Experimental Models ◽  
Initiation And Propagation ◽  
Organ Systems ◽  
The Central Nervous System ◽  
Animal Models Of Epilepsy ◽  
Almost All ◽  
Gaseous Neurotransmitter ◽  
Models Of Epilepsy

Epilepsy is one of the leading neurological disorders and affects 1-2% of the world?s population. Generally, it is a result of an imbalance between excitatory and inhibitory phenomena in the central nervous system (CNS), but the mechanisms of its initiation and propagation still require further investigations. Experimental models represent one of the most powerful tools to better understand the mechanisms of epileptogenesis. Nitric oxide (NO) is gaseous molecule with pleiotropic physiological and pathological effects in almost all organ systems and intriguing biological relevance, especially in the CNS where it acts as a gaseous neurotransmitter. The role of NO in the generation of epilepsy is highly contradictory, since there is evidence of its anticonvulsive, as well as proconvulsive properties. Therefore, we will discuss in this review the involvement of NO-mediated signaling pathways in the mechanisms of epileptogenesis, taking into account the findings revealed in experimental studies on animal models of epilepsy.

Method of metrological self-checking of a strain gauge pressure sensor

Metrologiya ◽  
2020 ◽  
pp. 48-62
Author(s):  
Vladimir A. Larionov
Keyword(s):  
Strain Gauge ◽  
Supply Voltage ◽  
Experimental Studies ◽  
Pressure Sensors ◽  
Experimental Sample ◽  
Self Monitoring ◽  
Gauge Pressure ◽  
External Conditions ◽  
Temperature And Pressure ◽  
Overall Resistance

Existing methods of metrological self-monitoring of measuring sensors for temperature and pressure of technological industries are considered. The analysis of methods of metrological self-checking of strain gauge pressure sensors is carried out. Method is proposed based on measuring the supply voltage and voltage on the measuring diagonal of the bridge. The temperature of the strain gauge bridge is determined using a semiconductor thermistor installed near the bridge. This allows you to adjust the measured value of the total resistance of the bridge from the temperature of the bridge. With aging and exposure to external conditions, a change in the overall resistance of the bridge can be used to judge the error of the sensor. An experimental sample of the sensor was made. The failure of the strain gage bridge is simulated by parallel connection of an additional resistor to one of the shoulders of the bridge. Experimental studies have shown that modern technical means make it possible to assess the effect of changes in the total bridge resistance on the sensor error.

Experimental studies of the operation dynamics of the motion neuro regulator of a nonlinear dynamic system

2021 ◽  
pp. 26-41
Author(s):  
Yu. Romasevych ◽  
◽  
V. Loveikin ◽  
A. Shevchuk ◽  
I. Bolbot ◽  
...  
Keyword(s):  
Angular Velocity ◽  
Dynamic System ◽  
Nonlinear Dynamic ◽  
Supply Voltage ◽  
Experimental Studies ◽  
Control Process ◽  
Nonlinear Dynamic System ◽  
Quality Of Control ◽  
Control Stability

In the article, experimental studies of the neurocontroller of a laboratory installation of a quadrocopter link are presented. The latter is a nonlinear dynamic system. The input vector of the neurocontroller included the angle of inclination of the rod (a beam of the quadcopter) relative to the horizon, its angular velocity, and the angular velocity of the propeller. The output signal of the neurocontroller is proportional to the supply voltage of the propeller drive. In the article, the planning of experimental studies was carried out and eight indicators were selected, according to which the quality of the control process was evaluated. In addition, a qualitative analysis of the control process of the dynamic system motion was carried out with the corresponding graphical dependencies. The data obtained showed a good quality of control at a zero setpoint angle. For other values of the setpoint (-0.52 and -1.05 rad), the neurocontroller provides the rod aboutness to the setpoint angle and the control stability. However, the quality of control is not high. The reason for this effect has been established in the work. In order to improve the quality of control, the neurocontroller was modified by including an integral component in its structure. At the same time, the steady-state control error has significantly decreased with minor changes in other estimated indicators.

scholarly journals Hydrodynamics of an in-pond raceway system with an aeration plug-flow device for application in aquaculture: an experimental study

2019 ◽  
Vol 6 (7) ◽  
pp. 182061 ◽  
Author(s):  
Wuhua Li ◽  
Xiangju Cheng ◽  
Jun Xie ◽  
Zhaoli Wang ◽  
Deguang Yu
Keyword(s):  
Water Flow ◽  
Plug Flow ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
High Water ◽  
Secondary Flows ◽  
Commercial Application ◽  
Flow Device ◽  
Intensive Aquaculture

An in-pond raceway system (IPRS) is an effective intensive aquaculture practice for regions with high water consumption and limited land resources. Water flow and dissolved oxygen (DO) are important for sustainable aquaculture. Several innovations have been made in IPRS design and operation to increase water exchange and DO concentration; one of these is the aeration plug-flow device (APFD). The APFD is commonly used in China as the only power source for water recirculation in aquaculture ponds. Understanding of the hydrodynamics of the system is necessary to improve the design of the IPRS with APFD. To this end, we performed experimental studies on a model system. We measured three-dimensional velocity at various locations using an Acoustic Doppler Velocimeter. Velocity distribution and turbulence characteristics were assessed, and plug-flow characteristics were analysed. Two patterns of velocity and turbulence in horizontal sections were observed: near the APFD, the water flow was intensively pushed downstream and simultaneously recirculated; farther away, the reflux area gradually decreased and the velocity and turbulence distribution trended towards uniform. Secondary flows occurred in different directions, which improved the diffusion of materials and DO retention. The system is effectively self-circulating, and the plug-flow capability may be scaled up for commercial application.

scholarly journals Ballast Flow Characteristics of Discharging Pipeline in Shield Slurry System

2019 ◽  
Vol 9 (24) ◽  
pp. 5402
Author(s):  
Yang Wang ◽  
Yimin Xia ◽  
Xuemeng Xiao ◽  
Huiwang Xu ◽  
Peng Chen ◽  
...  
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Flow Characteristics ◽  
Slurry Flow ◽  
Volumetric Concentration ◽  
Mass Percentage ◽  
Pipe System ◽  
Pipeline Wall ◽  
Slurry Flow Rate

We adopted two-way coupling of discrete and finite elements to examine the non-spherical ballast flow characteristics in a slurry pipe system during a shield project. In the study, we considered the slurry rheological property and the flake shape of the ballast. A ballast size between 17 and 32 mm under different slurry flow rates and ballast volumetric concentration conditions was investigated for determining the law through which the mass flow rate, detained mass percentage, and ballast distribution state are influenced. The results indicate that increasing slurry flow rate and the ballast volumetric concentration increase the mass flow rate; the influence of the latter is stronger. Increases in both in the slurry flow rate and the ballast volumetric concentration can reduce the detained mass percentage in the slurry discharging pipeline, whereas increasing the ballast size has the opposite effect. The increase in both the slurry flow rate and the ballast size changes the ballast motion state. Experiments verified the numerical lifting model of the ballast in the vertical pipeline. The measurements of the actual pipeline wall thickness verified that the simulation results regarding the ballast distribution were accurate.

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