The short-circuit flow, which is discharged from the vortex finder without separation, seriously affects the processing efficiency of the hydrocyclone. In this paper, the experimental test and numerical simulation methods are used to study the effect of the vortex finder and feed parameters on the short-circuit flow and separation performance. The Reynolds Stress method (RSM), Volume of Fluid (VOF), and Mixture model were adopted to predict the separation process in the hydrocyclone. The simulation results are analyzed in terms of the short-circuit flow rate, the ratio of the short-circuit flow rate to the inlet flow rate (hereafter this paper will be abbreviated as “its ratio”) and the separation efficiency. The results indicate that the smaller vortex finder diameter, thick-walled vortex finder, and moderate vortex finder length are conducive to inhibiting the short-circuit flow and decreasing the cut size (d50). A faster inlet velocity and higher feed concentration could increase th... [more]

The performance of low-pressure axial flow fans is directly affected by the three-dimensional bending and twisting of the blades. A new blade design method is adopted in this work, where the radial distribution of blade angle and blade bending angle is composed of standard-form rational quadratic Bézier curves. Dendrite Net is then trained to predict the pneumatic performance of the fan. A non dominated sorting genetic algorithm is employed to solve the global optimization problem of the total pressure coefficient and efficiency. The simulation results show that the optimal blade load distribution along the radial direction becomes uniform, and the suction surface separation vortex and passage vortex are restrained. On the other hand, the tip leakage vortex is enhanced and moves toward the blade leading edge. According to the experimental results, the maximum efficiency increases by 5.44%, and the maximum total pressure coefficient increases by 2.47% after optimization.

The stress-relief coal mine methane surface gas venthole is considered an effective method by which to realize coal mine methane exploitation and outburst prevention. Existing stress permeability models for caved zones, fractured zones, and bending subsidence zones were embedded into FLAC3D simulation software by using the FISH language. In cooperation with the in-situ data of a mine in a Huainan coalfield, the permeability distribution of pressure-relief surface gas drainage via different zones was simulated. The results indicated that the surface gas ventholes were effective for gas extraction from mining areas. By analyzing the distribution of permeability, three zones were identified: (1) the fully compacted zone, (2) the gradually compacted zone, and (3) the “O” type fractured zone. The seepage path of pressure-relief surface gas drainage was visualized. Most of the gas seeps into the adjacent rock mass at first and then is extracted through surface gas ventholes. Meanwhile, seepa... [more]

Industry 4.0 integrates a series of emerging technologies, such as the Internet of Things (IoT), cyber-physical systems (CPS), cloud computing, and big data, and aims to improve operational efficiency and accelerate productivity inside the industrial environment. This article provides a series of information about the required structure to adopt Industry 4.0 approaches and a brief review of related concepts to finally identify challenges and research opportunities to envision the adoption of so-called digital twins. We want to pay attention to upgrading older systems aiming to provide the well-known advantages of Industry 4.0 to such legacy systems as reducing production costs, increasing efficiency, acquiring better robustness of equipment, and reaching advanced process connectivity.

Machine learning (ML) approaches have risen in popularity for use in many oil and gas (O&G) applications. Time series-based predictive forecasting of hydrocarbon production using deep learning ML strategies that can generalize temporal or sequence-based information within data is fast gaining traction. The recent emphasis on hydrocarbon production provides opportunities to explore the use of deep learning ML to other facets of O&G development where dynamic, temporal dependencies exist and that also hold implications to production forecasting. This study proposes a combination of supervised and unsupervised ML approaches as part of a framework for the joint prediction of produced water and natural gas volumes associated with oil production from unconventional reservoirs in a time series fashion. The study focuses on the pay zones within the Spraberry and Wolfcamp Formations of the Midland Basin in the U.S. The joint prediction model is based on a deep neural network architecture leverag... [more]

The experimental and numerical analysis of pyridine adsorption onto activated carbon cloth in a stirred batch adsorber under transition and turbulent regime is presented in this work. Three-dimensional numerical modeling of the adsorption process was implemented for the identification of local velocity, local concentration, and concentration gradients inside the adsorber. This represents a costly computational effort in comparison with conventional batch adsorption models, as for instance the Langmuir kinetic model. Both types of modeling yield comparable results, but the advantage of the 3D modeling is a more detailed resolution of variables, thus avoiding the perfectly mixed assumption. Varying the agitation rate (30−200 rpm) and pyridine initial concentration (99 to 487 mg/L), several kinetic and transport parameters were reported. Hydrodynamic and mass boundary layers are identified around the activated carbon adsorbent following the trajectory of agitation. Furthermore, the major... [more]

Process chromatography modelling for process development, design, and optimization as well as process control has been under development for decades. Still, the discussion of scientific potential and industrial applications needs is open to innovation. The discussion of next-generation modelling approaches starting from Langmuirian to steric mass action and multilayer or thermodynamic consistent real and ideal adsorption theory or colloidal particle adsorption approaches is continued.

Flash calculations, including phase split and phase classification for both n-octane/water blends and paraffinic aromatic synthetic naphtha (PASN)/water blends present significant computational challenges. Calculations to establish the two-phase and three-phase regions, as well as the transitions between regions, were addressed by a phase classification method proposed in a recent contribution involving machine learning (ML). This work focusses on the phase-split calculations, considering (a) the lack of numerical convergence of the traditional calculations and their related numerical issues for water/n-octane and PASN/water systems based on the Rachford−Rice derived surfaces and (b) the successful implementation of an ML approach based on a K-nearest-neighbor (KNN) algorithm, which uses the abundant experimental data obtained in a CREC-VL cell.

Solid-liquid two-phase flow centrifugal pumps are widely used in many fields closely related to economic development, such as energy exploitation, and the petrochemical industry. Many scholars have studied the influence of solid particles with different parameters on the transportation performance of centrifugal pumps but have mainly focused on the study of low-concentration single-component particles, and the research on the transportation of high-concentration binary mixture particles in centrifugal pumps is insufficient. In this paper, two kinds of glass beads (0.4 mm and 2 mm) were mixed as a solid phase medium, representing small particles and large particles, respectively. The effects of a high concentration (Cv = 10%) of binary mixture particles on the transport and wear characteristics of a solid-liquid centrifugal pump were analyzed by simulation and experiment. Computational Fluid Dynamics-Discrete Element Method (CFD-DEM) and Archard wear model were used for simulation, real... [more]

In practice, the modeling and analysis of nonlinear rotor-bearing systems are difficult due to the nonlinearity and complexity. In the previous studies, finite element simulation and mathematical modeling methods are mostly adopted to conduct the analysis. However, due to the time-consuming problem in finite element simulation and the lack of sufficient prior knowledge in mathematical modeling, the traditional method is difficult to establish the representation model. In order to overcome this issue, in this study, a data-driven model referred to as the NARX (Nonlinear Auto-Regressive with exogenous inputs) model is introduced to conduct the modeling and analysis of the rotor-bearing system. The identification of the NARX model requires random excitation as the system input, while the input signal of the rotor system is harmonics. Therefore, a time-domain frequency sweep modeling method is proposed in this paper by introducing the rotating speed into the coefficients function expressio... [more]

A prediction method applicable to erosion-prone areas of fluorine chemical pipelines is herein proposed. By summarizing the common working conditions in the fluorine chemical industry, a computational fluid dynamics (CFD) model for industrial pipelines is established, and three-dimensional numerical calculations of the flow field in the pipelines are carried out to analyze the characteristics of the hydrodynamic parameters and phase distribution in the flow field, as well as the erosion rate distribution in different areas of the pipelines. The areas in the pipeline that are susceptible to erosion are predicted based on the results. The method has universal applicability and has been applied in many large petrochemical companies. It achieves the function of predicting the areas of severe pipeline erosion in a scientifically sound manner. This paper also details the application of the method in a distillation oil and gas pipeline of a large oil and gas company in western China.

As an excellent reducing agent, lime has an important role in the steel production process. Annular Shaft Kiln (ASK) has been widely used in the lime production industry for its low cost, low footprint, high chemical activity, easy construction, and easy maintenance. Due to the high temperature generated inside ASK during operation, it is hard to observe the limestone decomposition process and the field distribution in the lime kiln. The simulation analysis of temperature field, velocity field and decomposition field in the limestone calcination process by CFD provides practical guidance for future lime product quality control, ASK design and operation parameters’ control. This study is based on an ASK that was put into production. Based on the finite volume method, this paper combines the porous medium model and the shrinking core model to establish a set of mathematical models that can describe the temperature and flow field distribution inside the ASK, as well as the limestone decom... [more]

Taking the closed modification of an open sump of a water treatment pump station as the research background, the hydraulic design criteria for the closed modification of the sump are put forward by combining numerical simulation, model test. Based on CFD technology, a water pumping station including closed sump, bellmouth, impeller, guide vane, elbow and outlet sump is simulated, and the hydraulic performance of the schemes under different parameters is analyzed and compared. The top floor clearance, width, back wall distance, and floor clearance of the sump are optimized hydraulically, and the hydraulic design criteria of the closed sump are obtained. The results show that when the recommended optimization parameters of the closed sump in this study are that the top floor height HD is 0.9 DL, the width B is 3.0 DL, the back wall distance T is from 0.4 DL, and the floor clearance C is 0.75 DL, the internal flow pattern and hydraulic of the closed sump is better. (DL is the diameter of... [more]

A wellhead multistage bundle gas−liquid separator combining a gas−liquid cylindrical cyclone (GLCC) with multi-tube bundle components is expected to improve the gas−liquid separation performance. However, there is no unified understanding of the factors influencing the separation performance of the separator. The continuous improvement and applications of the separator are restricted. This paper evaluated the performance of the separator using a numerical simulation method. The results indicate that the separation flow field evolves to be uniform with the increased water cut when the gas−oil ratio and flow rate remain constant. Compared with a 30% water cut, the separation efficiency at a 50% water cut increased by 5.88%. When the gas−oil ratio and water cut remained constant, the swirl effect of the primary separation was enhanced. The separation efficiency increased to more than 70% when the flow rate was 15 m/s. When the flow rate and water cut remained unchanged, the pressure of th... [more]

The three products hydrocyclone screen (TPHS), a branch of the hydrocyclone, effectively removes the fish-hook effect, which has been used in the industrial field. The current cylindrical screen in the TPHS generates the characteristic flow known as the screen underflow, which has a significant impact on device performance. To investigate the flow behaviour of the fluid passing through the screen, a combination of a dynamic analysis and a numerical simulation was used. The permeating process in the TPHS was abstracted by a simple fan mode in this work to generate the flow-rate equations and the driving-force models. The pressure difference was the driving force for the screen penetration in the ideal fluid, but it also included a viscous force in the viscous fluid. Furthermore, at the same inlet velocity, the viscous fluid had a higher flow rate than the ideal, indicating that the viscosity promoted the fluid penetration. Meanwhile, as the inlet velocity increased, the mass flow of the... [more]

This paper presents the development of prediction models for pressure loss and classification efficiency in classifiers. Classifiers belong to one of the most important classification devices in gas particle processing and a fast and accurate determination of pressure loss and cut size is of great interest. The first model developed in this work allows the calculation of pressure loss as a function of geometric and operational parameters. It is based on a number of measured values that are obtained from previous numerical simulations (CFD). The maximum deviation of the model is less than 20% and the model operates in real time. However, the model requires calibration for each type of classifier. The second model for classification efficiency is based on a simplified two-dimensional approach in which the flow profile and particle trajectories are determined exclusively for the area between two classifier blades. The model is applicable for all geometrical and operational parameters and... [more]

Spent zinc−manganese batteries contain heavy toxic metals that pose a serious threat to the environment. Recovering these metals is vital not only for industrial use but also for saving the environment. Recycling metal from spent batteries is a complex task. In this study, machine-learning-based predictive models are developed for predicting metal recovery from spent zinc−manganese batteries by studying the energy substrates concentration, pH control of bioleaching media, incubating temperature and pulp density. The main objective of this study is to make a detailed comparison among five machine learning models, namely, linear regression, random forest regression, AdaBoost regression, gradient boosting regression and XG boost regression. All the machine learning models are tuned for optimal hyperparameters. The results from each of the machine learning models are compared using several statistical metrics such as R2, mean squared error (MSE), mean absolute error (MAE), maximum error an... [more]

As people pay ever-increasing attention to the problems caused by psychological stress, research on its influencing factors becomes crucial. This study analyzed the Health Information National Trends Survey (HINTS, Cycle 3 and Cycle 4) data (N = 5484) and assessed the outcomes using descriptive statistics, Chi-squared tests, and t-tests. Four machine learning algorithms were applied for modeling: logistic regression (linear), random forests (RF) (ensemble), the artificial neural network (ANN) (nonlinear), and gradient boosting (GB) (ensemble). The samples were randomly assigned to a 50% training set and a 50% validation set. Twenty-six preselected variables from the databases were used in the study as predictors, and the four models identified twenty predictors of psychological distress. The essence of this paper is a binary classification problem of judging whether an individual has psychological distress based on many different factors. Therefore, accuracy, precision, recall, F1-scor... [more]

A numerical simulation was carried out to investigate the blood flow behavior (i.e., flow rate and pressure) and coupling of a renal vascular network and the myogenic response to various conditions. A vascular segment and an entire kidney vascular network were modeled by assuming one single vessel as a straight pipe whose diameter was determined by Murray’s law. The myogenic response was tested on individual AA (afferent artery)−GC (glomerular capillaries)−EA (efferent artery) systems, thereby regulating blood flow throughout the vascular network. Blood flow in the vascular structure was calculated by network analysis based on Hagen−Poiseuille’s law to various boundary conditions. Simulation results demonstrated that, in the vascular segment, the inlet pressure Pinlet and the vascular structure act together on the myogenic response of each individual AA−GC−EA subsystem, such that the early-branching subsystems in the vascular network reached the well-regulated state first, with an inte... [more]

The flow heat transfer and stress distribution of the shell and tube superheater of the steam generation system in a 50 MW molten salt tank solar thermal power station are studied by numerical simulation, and the influence of the flow pattern of molten salt and water vapor in the shell-and-tube superheater on the heat transfer efficiency and stress distribution under the heat−fluid−solid coupling condition is deeply studied. When the water vapor is located on the tube side of the superheater, the molten salt is located on the shell side, and the counterflow is used in the superheater, the water vapor outlet meets the inlet temperature of the steam turbine, and the heat exchange efficiency of the superheater can reach 94.2%. The optimum inlet temperatures of molten salt and steam in the superheater are 563 and 345 °C, respectively, and the optimum flow rate of molten salt at the inlet of the superheater is 2.5 m/s. Compared with the stable condition, the heat exchange efficiency can be... [more]

The present work focuses on investigating the residence time behavior of microparticles in a concurrent downer reactor through experiments and numerical simulations. For the numerical simulations, a three-dimensional multiphase model was developed using the Euler-Lagrange approach. The experiments were performed in a 0.8 m-long steel reactor with gravitational particle injection. The effects of different operating conditions, e.g., the sheath gas velocity on the particle residence time distribution were assessed. An increase in the sheath gas flow rate led to a decrease in the peak residence time, although the maximum residence time increased. Regarding the lowest sheath gas flow rate, the particles’ peak residence time was twice as high compared to the peak residence time within the highest flow rate. The particles’ residence time curves presented a broad distribution coinciding with the size distribution of the powder. The numerical results agreed with the experimental data; thus, th... [more]

In the present study, imperative parameters including centrifugal force, erosion, streamline, strain rate, and wall shear are evaluated in a cyclone separator. The flaw of the cyclone surface due to erosion is an acute problem in the industry. According to the great importance of the centrifugal force on the separation phenomenon, a comprehensive study is conducted. A computational fluid dynamics (CFD) simulation is realized by applying a Reynolds stress turbulence model (RSM), and particle−air interactions were modeled using a discrete phase model (DPM). The result shows a good agreement between the experimental data and CFD simulation on the tangential velocity and pressure drop. The maximum deviation of the validation process is 6.8%. It is found that the centrifugal force within the cyclone is increased with an enhancement in the inlet velocity. The separation efficiency indicates an increase−decrease treatment in various inlet velocities with inlet velocity up to 16 m⋅s−1 but decr... [more]

The water cut (WC) has a significant effect on the flow parameters, such as liquid holdup, liquid phase velocity, and flow regimes of the low-viscosity oil−gas−water slug flow, and it can change the vibration characteristics of piping systems. To study the effect of water cut on the vibration characteristics of piping systems conveying such internal flow, a new dynamic model is developed. Galerkin’s method is used to discretize the equation and determine the natural frequencies by solving for the eigenvalues of the equation coefficient matrix. The results show that in the range of 10−90% WC, the natural frequency increases and then decreases, and the turning point occurs near the phase inversion region (WC = 40−60%). The main reason is the highly effective viscosity in the phase inversion region, which leads to an increase in the liquid holdup. The natural frequency increases and then decreases with superficial gas velocity, and the inflection point decreases with the increase in water... [more]

Coalescence-induced droplet jumping on superhydrophobic surfaces with different initial positions was numerically simulated using the 2D multi-relaxation-time (MRT) Lattice Boltzmann method (LBM). Simulation results show that for coalesced droplets with radii close to the structure length scale, the change of initial droplet positions leads to a significant deviation of jumping velocity and direction. By finely tuning the initial droplet positions on a flat-pillared surface, perpendicular jumping, oblique jumping, and non-jumping are successively observed on the same structured surface. Droplet morphologies and vector diagrams at different moments are considered. It is revealed that the asymmetric droplet detachment from the structured surface leads to the directional transport of liquid mass in the droplet and further results in the oblique jumping of the coalesced droplet. In order to eliminate the influence of initial droplet position on droplet jumping probability, a surface with p... [more]

The article investigated the flow of boiling streams through a nozzle with an oblique cut. Due to this flow organization, deviation from the nozzle axis at the vortex chamber inlet occurred. The study of flow modeling in the inlet section was carried out. The flow design and the calculation scheme of the vortex liquid−steam jet apparatus were proposed. Analytical expressions between the main operating parameters were obtained according to the developed mathematical model. A recommended oblique-cut angle for the active-flow nozzle was evaluated considering the transition through the first critical section based on the tangential velocity flow model. Validation of the mathematical model in the inlet section of the vortex chamber was provided based on the comparison with available experimental data. Flow visualization in the inlet section of the vortex chamber was obtained. The assumption of uneven flow distribution was confirmed experimentally. Overall, the boiling liquid flow was implem... [more]