Scale up validation tests for Buckingham Pi theorem applied to leaf test experiments for iron ore slurry

Reported are the results of an experimental programme to investigate the influence of mud composition, pressure and temperature on the properties of filter cakes formed during static filtration. Three water-based muds were tested at pressures up to 4.2 MPa and temperatures up to 93°C. The spurt loss, cumulative fluid loss, cake thickness and porosity were measured and, using a modified static filtration equation, the cake resistance and compressibility were calculated. The results clearly illustrate the highly compressible nature of filter cakes formed from drilling muds. Also shown is the profound influence of barite and temperature on the cake properties and fluid loss. Using expressions developed in the general field of solid-liquid separation for the variation in porosity within the filter cake, the behaviour of highly compressible cakes under pressure has been illustrated.

Practical and improved ordinary differential models for compressible filter cake buildup involving small particle invasion and deposition inside the cake at static and dynamic conditions are developed by averaging particle and carrier fluid transport equations over the filter cake thickness. The models are simplified by considering that the panicles and carrier fluids involving many practical applications are incompressible. The results of radial and linear filtration cases are compared for constant rate and constant pressure drive filtrations. This thickness‐averaged ordinary differential model reproduces the predictions of the Tien et al. (1997) partial differential model rapidly with less computational effort. Parametric studies indicate that the particle screening efficiency of the filter is an important factor on the filter cake properties and filtration rate, and differences between linear and radial cake filtration performances are more pronounced, and the cake thickness and filtrate volume are smaller for constant pressure filtration than constant rate filtration. The equations of the thickness‐averaged linear and radial filter cake formation models are simple requiring less computational effort over the reported partial differential models for the analysis, design and optimization of the industrial cake filtration processes involving plate and drum filters.

Multiphase flow models in quantifying constant pressure dead-end filtration and subsequent cake compression: 2. Concentrated slurry filtration and cake compression

The slurry was prepared by pre-hydration method in this study. The relationship between the content of bentonite in slurry and its cation exchange capacity was studied by changing the content of bentonite. After the density, funnel viscosity, filtrate volume and rheological properties of slurry were tested, the influence of cation exchange capacity on slurry performance and filter-cake quality was analyzed. The results showed that: When the cation exchange capacity of slurry is small, with the increase of cation exchange capacity, the funnel viscosity, apparent viscosity and plastic viscosity of slurry increase significantly, the filtrate volume decreases gradually, and the overall performance improves significantly, which can effectively form filter cake and maintain the stability of excavation surface; while when the cation exchange capacity exceeds a certain value, the funnel viscosity, apparent viscosity and plastic viscosity of slurry increase significantly. With the increase of cation exchange capacity, the filtrate volume and viscosity of the slurry still increase, and the filter cake performance tends to be stable, but its overall performance does not rise but fall. Considering the influence of cation exchange capacity on the slurry performance parameters, when the cation exchange capacity of the slurry is controlled around 7.58 i.e. the solid phase content is between 6% and 7%, the slurry filtrate volume is relatively small, and it is easy to form thin and compact filter cake with its best comprehensive performance.

Stevioside is one of the naturally occurring sweetener, which can be widely applied in food, drinks, medicine, and daily chemicals. Membrane separation has potential application in clarification of stevioside from pretreated stevia extract by ultrafiltration. In the present study, namely 5-, 10-, 30-, and 100-kDa molecular weight cutoff membranes have been used. Quantification of membrane fouling during ultrafiltration is essential for improving the efficiency of such filtration systems. A systematic analysis was carried out to identify the prevailing mechanism of membrane fouling using a batch unstirred filtration cell. It was observed that the flux decline phenomenon was governed by cake filtration in almost all the membranes. For 100 kDa membrane, both internal pore blocking and cake filtration are equally important. Resistance in series analysis shows that the cake resistance is several orders of magnitude higher than the membrane resistance. The cake resistance is almost independent of transmembrane pressure drop, which indicates the incompressible nature of the cake. A response surface analysis was carried out to quantify the development of cake resistance with time during ultrafiltration of various membranes. Quality parameters show that the 30-kDa membrane is better suited for clarification purposes. Identification of the fouling mechanism would aid in the process of design and scaling up of such clarification setup in future.

Influence of slip length on filtration performance of fine particles

Multiphase flow models in quantifying constant pressure dead-end filtration and subsequent cake compression: 1. Dilute slurry filtration

As high-pressure/high-temperature (HP/HT) drilling is inherently expensive, drilling fluids and technologies should be carefully selected to successfully handle the associated challenges. Over the past few years, nanoparticles (NPs), among other additives, have been investigated to address these challenges. The objective of this study is to investigate the potential of using ferric oxide NPs on the filter cake properties in downhle drilling environments. Having an efficient filter cake is an important property of the drilling fluid and can affect the success of drilling operations. This research focuses oncharacterizatingthe filter cakes produced by Ca-bentonite-based drilling fluid contains ferric oxide NPs at downhle conditions. A combination of computed-tomography (CT) scan and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) was used in filter cake characterization. The effect of NP concentration, fluid preparation method, and filtration condition were studied. A HP/HT filter press was used to perform the filtration process at conditions up to 350°F and 500 psi. Indiana limestone core disks were used to simulate the filter media. The experimental results showed that the ferric oxide NPs improve the filter cake and filtration properties of Ca-bentonite-based drilling fluid in the presence of polymer and other additives. Low NP concentration is preferred for obtaining a good cake quality with the best characteristics obtained at 0.3–0.5 wt% NPs. Furthermore, this drilling fluid can withstand conditions up to 500 psi and 350°F. Cake properties of 0.151 in. thickness, 6.9 ml filtrate volume, and 0.428 µd permeability was obtained at such conditions. The addition of NPs to the drilling fluid improved the filter cake properties under both static and dynamic filtration. SEM-EDS analysis confirmed the efficiency of using NPs to form a smoother/less porous filter cake morphology. Moreover, sonication for one hour and hydration for 16 hours are recommendedfor better preparation of these fluids. This research provides an experimental evaluation of using ferric oxide NPs with Ca-bentonite-based drilling fluid to produce high-quality filter cake at downhole conditions. The characteristics of the filter cake gererated confirmed the efficiency of such fluids.

Introduction. The existing methods of assessing the technical condition of power hydraulic cylinders do not allow one to conclude about the need to restore worn surfaces of parts. The data on limit values of wear of parts (wear and tear value at which a decision is made to repair) in technical requirements to overhaul and other technical documentation of hydraulic cylinders are not currently available. The aim of the study is to determine limit values of wear of working surfaces of hydraulic cylinder parts of C series. Materials and Methods.To assess the technical condition of hydraulic cylinders used, the authors developed a device on the basis of the stand KI-28097M-GOSNITI, equipped with an independent hydraulic station and load hydraulic cylinder, at which bench tests were carried out in the operation of С series hydraulic cylinders to determine overall efficiency values. Results. Results of bench and micrometer tests of the former hydraulic cylinders of the С series (С75/30, С90/30, С100/40) are presented. The regression model of the relationship between total efficiency of C series hydraulic cylinders (С75/30, С90/30, С100/40) and wear of working surfaces of parts was obtained. According to this regression model obtained using the method of steep ascent, limit values of wear of the working surfaces of C series hydraulic cylinder parts (С75/30, С90/30, С100/40) were determined. Discussion and Conclusion.19,5 % of hydraulic cylinders of С series (С75/30, С90/30, С100/40) were operated in an out-of-limit condition. In case of technical service companies carrying out the input control of to-be-repaired hydraulic cylinders, limit values of wear for hydraulic cylinder surfaces, determined by the method of steep ascent, allow for making proper decisions on the need of their restoration.

Ultrasonication-assisted fouling control during ceramic membrane filtration of primary wastewater under gravity-driven and constant flux conditions

<div class="section abstract"><div class="htmlview paragraph">In the quest for reduced cost and shorter development times for fuel cell systems in industrial applications, two major issues arise. First, the electrochemical behavior of fuel cell systems is inherently difficult to predict. Second, testing fuel cell systems is resource intensive. These issues compound: Setting up an accurate model of a fuel cell system incurs long testing periods for model validation. Further, it does not guarantee acceptable results outside the tested range or for other membrane electrode assembly compositions.</div><div class="htmlview paragraph">To mitigate these two major issues an X in the Loop concept is proposed. Essentially, this is the direct integration of the test sample, here a single fuel cell, into the modelling environment of the whole system. In practice, two strategies with different levels of integration are defined.</div><div class="htmlview paragraph">The first strategy consists of initially deducing the operating parameters of the sample cell from the fuel cell system model. Then, setting them to the sample cell in the test bench. The response of the test sample is finally used to validate the designed system or update the parameters of the fuel cell model.</div><div class="htmlview paragraph">The second strategy is a step further towards the integration of the test sample into the model. Here, the core model of the fuel cell inside the fuel cell system model is completely replaced with the test sample, reducing the need for an accurate electrochemical model while improving the prediction of the behavior of the fuel cell system.</div><div class="htmlview paragraph">Compared to previously proposed testing concepts, here the balance of plants is directly integrated through a digital emulator, leading to a closer representation of the complete system. Furthermore, the test bench results are looped back to the model at run-time leading to a closer match between testing conditions and the real world as well a reduced impact of inaccuracies in the modelling of the fuel cell.</div><div class="htmlview paragraph">On the way to realizing this goal, an experimental test bench capable of showcasing working prototypes of the proposed operating strategies has been built.</div></div>

The results of studies of the physical, mechanical and tribological characteristics of PVD and DLC coatings are presented. The complex of basic mechanical properties (hardness H and elastic modulus E), as well as derivatives of mechanical characteristics H/E and Н3/Е2 , were investigated by the method of continuous indentation at various loads. The friction coefficient, the wear rate of the sample and the counterbody were determined as tribological indicators. The applied purpose of the work was to determine the friction unit for applying the developed coatings, materials and modes of applying PVD and DLC coatings. To solve this problem, a test bench was designed and built that simulates the operation of the selected friction unit. As a result of the research carried out, the results of laboratory and bench tests were compared. The performance of the coatings was determined by the volume of the tooth wear of the sleeve and the tip with the help of the method of micrometric measurements. As a result of the study of the surface morphology, the volumes of wear of rubbing conjugations and the intensity of their wear were determined. It has been established that the results of bench tests confirm laboratory studies and suggest that such an installation can be used for researching other heavily loaded spline conjugations.

An electronic control unit (ECU) is designed for a compressed natural gas (CNG) engine on the basis of circuit simulation and modelling. The ignition drive circuit and power-off delay circuit are discussed, with emphasis on circuit simulation, and resistance matching for the sensor processing circuit is described. Design of the software of the CNG control system is based on modelling. A TargetLink model of an air—fuel ratio closed-loop control system is presented. The CNG ECU has been applied successfully in bench tests. The results of bench tests have shown that the hardware meets CNG control system requirements; actuators can be controlled precisely, and the performance of the CNG engine can reach design targets. Circuit simulation and modelling are good methods for developing the ECU design for CNG engine systems. Quality of hardware and software design can be ensured, and the development cycle and costs can be reduced.

This study presents a condition diagnosis system based on a ferrous particle sensor to estimate the durability of axles in construction equipment. Axles are mechanical devices that play the role of the differential gear in construction equipment that move with wheels and require high reliability. In the durability testing of new axles, failure identification and real-time diagnosis are required. One of the typical failure modes of an axle is increased ferrous-wear particles due to metal-to-metal contact. Therefore, a condition diagnostic program based on the ferrous particle sensor is developed and applied in the bench tests of axles. This program provides information on the amount of wear with respect to ferrous particles using a simple diagnostic algorithm. Additionally, it allows separation and storage of measured data that exceed the reference values; the system provides warnings using color, sound, and pop-up windows to facilitate diagnosis. In the two tests, the first case detected a failure, but in the other case, the sensor did not detect it even though a failure occurred. From the results of bench tests, it is confirmed that the sensor location is a critical factor. Therefore, a multi-physics-based analysis method is suggested for positioning the ferrous particle sensor.

The paper presents the study of heat transfer processes during prelaunch decreasing expenditure highways propulsion units (PU) upper stage (US) launch vehicles (LV) and cryogenic systems of the test bench (TB). Based on the consideration of the equations of conservation of mass and energy as applied to gas-cushion tank and the volume of the tank is filled with cryogenic fluid, the methods of mathematical simulation of processes of cooling. According to the results of bench and flight tests control coefficients are specified closing dependences on heat transfer and friction in heat capacity of the elements. TB and PU. The results of calculation and experimental studies of the processes of cooling consumable hydrogen and oxygen arteries obtained at bench and flight tests of RB, can be used for verification of computer models calculate during cryogenic systems TB and PU.