scholarly journals HYDROJET EJECTION HYDROMETER OF BULK MATERIALS. WORKFLOW AND CHARACTERISTICS

2020 ◽  
Vol 20 (1) ◽  
pp. 47-54
Author(s):  
E. К. Spiridonov ◽  
◽  
G. G. Yakubov ◽  
D. F. Khabarova ◽  
◽  
...  
Keyword(s):  
Relative Density ◽  
High Speed ◽  
Building Materials ◽  
Specific Energy Consumption ◽  
Outlet Section ◽  
Bulk Materials ◽  
Jet Pump ◽  
Jet Pumps ◽  
Underwater Mining ◽  
Sand And Gravel

Among hydrodynamic machines, jet pumps are among the most common. The high demand for this type of pump is due to their following features: the absence of moving parts and the simplicity of the device, small overall dimensions and weight, high self-priming ability, the ability to pump aggressive media and hydraulic mixtures containing solid impurities. In the hydromechanical method of developing deposits of building materials (sand, gravel, etc.), jet pumps – hydraulic elevators are used for underwater mining and transportation of bulk materials to the sorting plant, and after classification of the sand-gravel mixture – hydraulic transport of sand and gravel to dumps through pipelines. With this method of laying the finished product, the jet pump creates a static pressure of the hydraulic mixture, sufficient for its transport to the dump. However, another way of laying the finished product in dumps is also possible – through the air with a slurry stream. In this case, the jet pump performs the function of a hydrometer – a device for creating a high-speed slurry jet. A review of the literatureshowed that this mode of operation of the jet pump was not investigated. The effective operation of the jet pump-hydrometer depends on the ratio of the areas of the outlet section of the nozzle and the normal section of the mixing chamber, the relative density of the slurry in the input hopper. For each value of the relative density of the slurry, there is an optimal ratio of the areas of the nozzle and the chamber at which the specific energy consumption of the active stream will be minimal. The aim of this work is to determine and analyze the characteristics of an ejection hydrometer and to identify the most effective modes of its operation.

Modelling of Slurry-Handling Piping Element Under Interference Conditions

Volume 3 ◽  
2004 ◽  
Author(s):  
Prem Chand ◽  
K. Govinda Rajulu ◽  
Y. Krishna Reddy
Keyword(s):  
Particle Diffusion ◽  
Test Rig ◽  
Jet Pump ◽  
Two Phase ◽  
New Approach ◽  
Jet Pumps ◽  
Flow Through ◽  
Extensive Experimental Data ◽  
Fluid Interaction ◽  
Layer Concept

The paper presents a new approach to predict the two-phase performance of jet-pumps under interference conditions. We limit our study mainly to diffuser and transport regions of the jet pump. The five essential pre-requisites which form the backbone of our approach are a fairly generalized and accurate approach to (i) solid-fluid interaction, (ii) particle diffusion under generalized flow field, (iii) friction factor-Reynolds number equation, (iv) solid-fluid flow through ducts and (v) mixing of primary and secondary jets using the approach of Wang et al. [1] based on boundary layer concept. The extensive experimental data of several research workers along with fresh data generated on specially designed test-rig support the new approach.

scholarly journals Mycotoxins in Crude Building Materials from Water-Damaged Buildings

2000 ◽  
Vol 66 (5) ◽  
pp. 1899-1904 ◽  
Author(s):  
Tapani Tuomi ◽  
Kari Reijula ◽  
Tom Johnsson ◽  
Kaisa Hemminki ◽  
Eeva-Liisa Hintikka ◽  
...  
Keyword(s):  
Building Materials ◽  
Growth Conditions ◽  
Fungal Species ◽  
Aspergillus Versicolor ◽  
Chemical Analyses ◽  
Bulk Materials ◽  
Toxigenic Fungi ◽  
Three Samples

ABSTRACT We analyzed 79 bulk samples of moldy interior finishes from Finnish buildings with moisture problems for 17 mycotoxins, as well as for fungi that could be isolated using one medium and one set of growth conditions. We found the aflatoxin precursor, sterigmatocystin, in 24% of the samples and trichothecenes in 19% of the samples. Trichothecenes found included satratoxin G or H in five samples; diacetoxyscirpenol in five samples; and 3-acetyl-deoxynivalenol, deoxynivalenol, verrucarol, or T-2-tetraol in an additional five samples. Citrinine was found in three samples. Aspergillus versicolor was present in most sterigmatocystin-containing samples, and Stachybotrys spp. were present in the samples where satratoxins were found. In many cases, however, the presence of fungi thought to produce the mycotoxins was not correlated with the presence of the expected compounds. However, when mycotoxins were found, some toxigenic fungi usually were present, even if the species originally responsible for producing the mycotoxin was not isolated. We conclude that the identification and enumeration of fungal species present in bulk materials are important to verify the severity of mold damage but that chemical analyses are necessary if the goal is to establish the presence of mycotoxins in moldy materials.

In-Service Inspection Strategy for Alloy X-750 BWR Jet Pump Beams Based Upon Linear Elastic Fracture Mechanics Analysis

2009 ◽  
Author(s):  
Daniel V. Sommerville ◽  
Hardayal Mehta ◽  
Robert Carter ◽  
Jonathon Kubiak
Keyword(s):  
Fracture Mechanics ◽  
Pump Beam ◽  
Operating Experience ◽  
Linear Elastic Fracture Mechanics ◽  
Jet Pump ◽  
Linear Elastic ◽  
Flaw Tolerance ◽  
Beam Design ◽  
Jet Pumps ◽  
Elastic Fracture

Jet pumps in a boiling water reactor (BWR) are located in the annulus region between the core shroud and the reactor vessel wall and provide core flow to control reactor power. Between 16 and 24 jet pumps are included in BWR/3 through BWR/6 plants, depending on the plant rating. The inlet mixer assembly of the jet pump is secured in place with a hold down mechanism called a jet pump beam. This beam is fabricated of alloy X-750 and tensioned to 58–74% of the yield stress of the material, depending on the beam design. In recent years, more attention has been placed upon inter-granular stress corrosion cracking (IGSCC) of alloy X-750 BWR internal components as a result of in-service cracking and failures. BWR plant owners have implemented actions to manage IGSCC of jet pump beams and assemblies through increased inspections and changes to process specifications for X-750. However, a thorough understanding of the flaw tolerance of the jet pump beam was not available to guide the periodicity of inspections as well as to define critical flaw sizes needed to validate the capability of inspection techniques. This paper describes a linear elastic fracture mechanics (LEFM) evaluation in which the flaw tolerance of the existing jet pump beam designs is established and used to recommend inspection frequencies for the jet pump beam. Industry operating experience is used to assess the credibility of the results obtained from this evaluation. This work illustrates an example of the use of LEFM to develop a technically defensible basis for the required inspection regions and the frequency of inspection for an alloy X-750 BWR internal component and helps to establish the necessary sensitivity of non-destructive examination technology to be used to examine the component.

CFD Investigation of Global Performance and Three Dimensional Flows in a Water-Jet Axial Flow Pump

2005 ◽  
Author(s):  
Hong Gao ◽  
Wanlai Lin ◽  
Fangming Ye
Keyword(s):  
Three Dimensional ◽  
Axial Flow ◽  
Flow Fields ◽  
Water Jet ◽  
Jet Pump ◽  
Wall Functions ◽  
Global Performance ◽  
Jet Pumps ◽  
Axial Flow Pump ◽  
Radial Loading

The purpose of the present study is to investigate the global performance and three dimensional flow fields in a water-jet pump. TASCflow software is employed to simulate the rotator-stator coupling flow field. A standard k-ε turbulence model combined with standard wall functions is used. In order to investigate the effect of a rear stator on flow fields, the flows in two water-jet pumps with and without a rear stator are studied. The CFD predicted global performances are in good agreement with the experimental results. Then the flow fields, such as the pressure distribution on the blade surfaces, the axial and tangential velocities distribution, especially the radial loading distribution are investigated at different flow rates. In addition, the effect of a rear stator and different spacing between the rotor and the stator on the global performance and the flow fields of the water-jet pump are also investigated.

Jet Pump Noise Analysis for BWRs

2004 ◽  
Author(s):  
Rogelio Castillo-Dura´n ◽  
Javier Ortiz-Villafuerte ◽  
He´ctor Herna´ndez-Lo´pez ◽  
Gustavo Alonso-Vargas ◽  
Gabriel Calleros-Micheland
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Pressure Drop ◽  
Nuclear Power ◽  
Noise Analysis ◽  
Jet Pump ◽  
Operation Conditions ◽  
Jet Pumps ◽  
Process Computer ◽  
Abnormal Operation

The use of noise analysis for detection of BWR component malfunction is a powerful tool in determining abnormal operation conditions, during the life of a nuclear power plant. Since the 80s, several nuclear reactors have reported problems related with jet pumps and recirculation loops. The NRC, in the IE Bulletin 80-07, recommended performing periodic monitoring to individual pressure drop jet pumps, to prevent structural failure. In this work, noise analysis methods are used for detection of jet pumps abnormal operation conditions in a BWR. Power signals obtained from the backup process computer of a BWR are analyzed with a home-developed software, called NOISE, for noise diagnostic of power signals. The computer program takes individual signals from the tabular report of the process computer. The normalized power spectral density (NPSD) is then obtained, using a Prime Factor Algorithm to calculate the Fast Fourier Transform. The NPSD of the jet pumps pressure drop, of Unit 2 of the Laguna Verde Nuclear Power Plant, showed a noticeable change in jet pump 6 during 2003, considering the period from the startup test to operation during 2003. This abnormal condition was due to that the jet pump throat was partially blocked. The noise analysis methodology is shown to be a useful tool for malfunction detection, and could be applied to create a data bank for monitoring the dynamic behavior of BWR jet pumps.

Theoretical Modeling of Central Air-Jet Pump Performance for Pneumatic Transportation of Bulk Solids

1999 ◽  
Vol 121 (2) ◽  
pp. 365-372 ◽  
Author(s):  
D. Wang ◽  
P. W. Wypych
Keyword(s):  
Analytical Procedure ◽  
Area Ratio ◽  
Jet Pump ◽  
Pump Performance ◽  
Bulk Solids ◽  
Air Jet ◽  
Performance Predictions ◽  
Jet Pumps ◽  
Pneumatic Transportation ◽  
Good Agreement

A mathematical model to predict the air-solids performance of central air-jet pumps has been developed based on the fundamentals of fluid and particle mechanics. The influence of throat entry configuration on performance has been incorporated into the analytical model by introducing a throat entry function and suction area ratio. Nondimensional parameters to represent air-solids jet pump performance has been defined and used in the analytical procedure. The performance predictions obtained by this model show good agreement with experimental results.

scholarly journals Analysis of massive sulphate attack to cement-treated compacted soils

2020 ◽  
Vol 195 ◽  
pp. 01009
Author(s):  
Anna Ramon-Tarragona ◽  
Eduardo Alonso
Keyword(s):  
High Speed ◽  
Good Evidence ◽  
Railway Track ◽  
Active Volume ◽  
Sulphate Content ◽  
Compacted Soils ◽  
Cement Interface ◽  
Railway Line ◽  
Long Time ◽  
Sand And Gravel

The paper describes the heave experienced by two embankments providing access to a bridge located in a high-speed railway line. The compacted soil, a mixture of a low plasticity clay, sand and gravel, had a significant sulphate content (2 – 2.5%). The embankments received a reinforcing treatment by mixing the soil with cement in the proximity of the bridge abutments. In addition, a grid of grouting columns provided more stiffness to the embankments. The embankments experienced a fast heaving rate (around 4 mm/month) in the areas improved by cement mixing. Precision extensometers indicated that heave concentrated in the upper 6 – 8 m of the embankments. The sulphate content reduced sharply to 0.25% at increasing depth. No heave was detected in these deeper zones. The swelling was found to be associated with the development of thaumasite and ettringite minerals. The presence of clay, cement and sulphates in the compacted soils and the infiltration of water from rainfall events are ideal conditions for the growth of the mentioned minerals. Long-term tests performed on compacted samples provided a good evidence of the phenomena developing in situ. A chemical modelling of the mineral changes at the soil-cement interface provided an additional insight into the development of swelling, which could last for a long time (several years). Accordingly, it was decided to underpin the railway track and to excavate the upper active volume of the embankments. This solution went in parallel with train service, which was never interrupted.

scholarly journals ANALYTICAL DESCRIPTION OF THE MIXER PERFORMANCE FOR BULK MATERIALS WITH SCREW BLADES

2019 ◽  
pp. 69-78 ◽  
Author(s):  
Марина Борисова ◽  
Marina Borisova ◽  
Владимир Новиков ◽  
Vladimir Novikov ◽  
Владимир Коновалов ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Animal Feed ◽  
Bulk Material ◽  
Specific Energy Consumption ◽  
Analytical Description ◽  
Bulk Materials ◽  
Rotating Shaft ◽  
Discharge Opening ◽  
Horizontal Shaft ◽  
Blade Mixer

The aim of the study is to reduce the energy consumption of the blade mixer for bulk materials in regard to its de-sign parameters. Preparation of feed mixtures is carried out mainly by mixers of various designs, as well as extrud-ers and other auger equipment. Widespread horizontal mixers with blades mounted on a rotating shaft are wide-spread and used. They are distinguished by the ability to achieve the necessary smooth mixture within short oper-ating time. The main purpose of the proposed mixer is the preparation of dry mixtures of bulk feed components. The intended use of the mixer is the preparation of concentrated animal feed n agricultural production. In Samara SAA, the design of the blade mixer with screw blades was developed based on the literature review and analysis of the technological process of mixers. The mixer consists of a body with a horizontal shaft with radial trapezoidal screw blades. The proposed blades allow to direct forces in such a way that the total (resulting) projection of the resistant force of the material along the shaft will tend to zero due to the changing angle of the profile and width of the blades. At the same time, an axial force will be created at the edge of the blade at a certain radius, which facili-tates to unload mixer through the discharge opening. The expressions of specific energy consumption for mixing, as well as the work duration of the mixer cycle are given. An expression allowing estimation of an average flow rate of bulk material from the discharge opening of the mixer is obtained. It is established that the position of the gate regulating the area of the discharge opening can affect the volume of the portion simultaneously processed by the mixer, filling volume of mixer and the quality of the mixture.

scholarly journals RESEARCH RESULTS OF THE IMPROVED HYDRAULIC JET PUMPING UNIT

2020 ◽  
Vol 6 (444) ◽  
pp. 14-22
Author(s):  
Sh. A. Abdreshov ◽  
◽  
A. E. Aldiyarova ◽  
E. T. Kaypbaev ◽  
◽  
...  
Keyword(s):  
Experimental Model ◽  
Laboratory Tests ◽  
Experimental Studies ◽  
Jet Pump ◽  
Ejection Coefficient ◽  
Jet Pumps ◽  
Useful Flow ◽  
Pumping Unit ◽  
Pumping Units

The scientific article is aimed at substantiating the classification of hydraulic jet pumping units, developing an experimental model of an improved hydraulic jet pumping unit, conducting experimental studies - determining the useful flow Qгн depending on the flow rate of the centrifugal pump used Qн for two variants of the pumping unit operating according to the traditional and alternative technology of water lifting, determination of the head losses hснi and friction coefficients ξснi in jet pumps, increasing the ejection coefficient Ke from the swirl parameter S of water supply to the intake chamber of the jet pump and laboratory tests of the hydraulic jet pumping unit for agricultural water supply and irrigation of pastures. The results of experimental studies and laboratory tests of an experimental model of an improved water-jet pumping unit, developed at NAO KazNAU, are presented. An analysis is given of the results of comparative tests of a hydraulic jet pumping unit for two variants of the technological process: an alternative and a traditional one with an increase in the effective supply of an alternative option by 2-4 times, a decrease in the required pressure by 1.5-2 times and an increase in efficiency by 1.1-2 times. The aim of the study is to obtain results to substantiate the classification of hydraulic jet pumping units, to carry out experimental studies and laboratory tests of an improved hydraulic jet pumping unit operating according to an alternative water lifting technology, which allows to reduce the required head of the pumping unit, increase the useful flow and increase the efficiency of the improved hydraulic jet pumping unit. The work used patent research with a review of works that were carried out according to existing methods: identifying close analogues, analyzing existing works and using them in development. Experimental studies were carried out to study the technological process of water rise from wells, the processes occurring in the used jet pumps - determining the useful flow depending on the flow of a centrifugal pump, determining the pressure losses and friction coefficients in jet pumps, the ejection coefficient and checking the reliability of the theoretical assumptions obtained. Based on the analysis of the work performed and patent research on technologies for lifting water from underground water sources by hydraulic jet pumping units and designs developed for them, a substantiated classification of hydraulic jet pumping units is proposed, which allows, depending on the task at hand, to correctly choose the necessary structural and technological scheme, type of jet pump and its implementation in the development of the required effective standard sizes of the hydraulic jet pumping unit. The scheme of the test bench and the experimental model of the improved hydraulic jet pumping unit with measuring equipment and instruments for conducting experimental research and laboratory tests on a bench well is presented.

scholarly journals Procedure for the recovery of the mined area in the deposit gravel - sand Rio Sagua, Holguin. Cuba

2014 ◽  
pp. 18-25
Author(s):  
Alexis Montes de Oca-Risco ◽  
Mayda Ulloa-Carcassés ◽  
Suraymi García-Cruz
Keyword(s):  
Building Materials ◽  
Construction Materials ◽  
Mining Activity ◽  
Strong Impact ◽  
Scientific Methods ◽  
Factors Influencing ◽  
The Social ◽  
Gravel Pits ◽  
Sand And Gravel ◽  
Flooded Areas

The gravel pits are exploitations to extract granular materials, sand and gravel in the alluvial river areas. Excavated voids are not very deep, unlike quarries and generally result in flooded areas. The company building materials in Holguin province has concessioned four deposit and within a gravel pit. The areas damaged by the exploitation of construction materials in the territory occupy about 75 ha, which causes a strong impact on the environment. For this reason it is proposed to develop a procedure to recover the deposit mined area in the gravel - sand Rio Sagua de Holguín as to achieve responsible mining. With the application of scientific methods analyzed the factors influencing the choice of recovery uses the mined area in the study area and developed a procedure consisting of five main stages. With the development of the procedure was shown that it can improve the social and environmental quality in the area affected by the mining activity.

Sign in / Sign up

Export Citation Format

Share Document