In this study, a numerical approach was adopted in order to explore the analysis of magneto fluid in the presence of thermal radiation combined with mixed convective and slip conditions. Using the similarity transformation, the axisymmetric three-dimensional boundary layer equations were reduced to a self-similar form. The shooting technique, combined with the Range−Kutta−Fehlberg method, was used to solve the resulting coupled nonlinear momentum and heat transfer equations numerically. When physically interpreting the data, some important observations were made. The novelty of the present study lies in finding help to control the rate of heat transfer and fluid velocity in any industrial manufacturing processes (such as the cooling of metallic plates). The numerical results revealed that the Nusselt number decrease for larger Prandtl number, curvature, and convective parameters. At the same time, the skin friction coefficient was enhanced with an increase in both slip velocity and con... [more]

Sulphuric acid (H2SO4) is one of the most produced chemicals in the world. The critical step of the sulphuric acid production is the oxidation of sulphur dioxide (SO2) to sulphur trioxide (SO3) which takes place in a multi catalytic bed reactor. In this study, a representative kinetic rate equation was rigorously selected to develop a mathematical model to perform the multi-objective optimization (MOO) of the reactor. The objectives of the MOO were the SO2 conversion, SO3 productivity, and catalyst weight, whereas the decisions variables were the inlet temperature and the length of each catalytic bed. MOO studies were performed for various design scenarios involving a variable number of catalytic beds and different reactor configurations. The MOO process was mainly comprised of two steps: (1) the determination of Pareto domain via the determination a large number of non-dominated solutions, and (2) the ranking of the Pareto-optimal solutions based on preferences of a decision maker. Re... [more]

In the process of the exploitation of deep oil and gas resources, shale wellbore stability control faces great challenges under complex temperature and pressure conditions. It is difficult to reflect the micro mechanism and process of the action of inorganic salt on shale hydration with the traditional experimental evaluation technology on the macro effect of restraining shale hydration. Aiming at the characteristics of clay minerals of deep shale, the molecular dynamics models of four typical cations (K+, NH4+, Cs+ and Ca2+) inhibiting the hydration of clay minerals have been established by the use of the molecular dynamics simulation method. Moreover, the micro dynamics mechanism of typical inorganic cations inhibiting the hydration of clay minerals has been systematically evaluated, as has the law of cation hydration inhibition performance in response to temperature, pressure and ion type. The research indicates that the cations can promote the contraction of interlayer spacing, com... [more]

Drug repositioning is a well-known method used to reduce the time, cost, and development risks involved in bringing a new drug to the market. The rapid expansion of high-throughput datasets has enabled computational research that can suggest new potential uses for existing drugs. Some computational methods allow the prediction of potential drug targets of a given disease from a systematic network. Despite numerous efforts, the path of many drugs’ efficacy in the human body remains unclear. Therefore, the present study attempted to understand drug efficacy by systematically focusing on functional gene sets. The purpose of this study was to carry out modeling to identify systemic gene networks (called drug paths) in drug-specific pathways. In our results, we found five different paths for five different drugs.

This paper presents a research study which is dedicated to the improvement in retail warehouse activity. This study aims to improve activity by identifying an efficient order picking strategy. (1) Background: The literature review shows the application of order picking strategies, but research related to their selection lacks an integrated approach. (2) Methods: The authors use the discrete event simulation method for the analysis of order picking strategies. The application of the discrete event simulation method enables various scenario tests in retail warehouses, allowing one to benchmark order picking strategies. By using the simulation model, experiments were designed to evaluate order picking strategies that are dependent on the delivery of the product distance variable. This research uses analysis of cost components and helps to identify the best possible order picking strategy to improve the overall warehouse performance. The authors benchmarked order picking strategies and pre... [more]

When a commercial vehicle is driving with the sunroof open, it is easy for the problem of sunroof buffeting noise to occur. This paper establishes the basis for the design of a commercial vehicle model that solves the problem of sunroof buffeting noise, which is based on computational fluid dynamics (CFD) numerical simulation technology. The large eddy simulation (LES) method was used to analyze the characteristics of the buffeting noise with different speed conditions while the sunroof was open. The simulation results showed that the small vortex generated in the cab forehead merges into a large vortex during the backward movement, and the turbulent vortex causes a resonance response in the cab cavity as the turbulent vortex moves above the sunroof and falls into the cab. Improving the flow field characteristics above the cab can reduce the sunroof buffeting noise. Focusing on the buffeting noise of commercial vehicles, it is proposed that the existing accessories, including sun visor... [more]

In a steel-refining ladle, the properties of manufactured steel can be notably degraded due to the presence of excessive inclusions. Stirring via gas injection through a porous plug is often used as part of the steel-refining process to reduce these inclusions. In this paper, 3D computational fluid dynamics (CFD) modeling is used to analyze transient multiphase flow and inclusion removal in a gas-stirred ladle. The effects of gas stirring with bubble-inclusion interaction are analyzed using the Euler−Euler approach for multiphase flow modeling, while the effects of inclusions aggregation and removal are modeled via a population balance model (PBM).

The aerodynamic performance of the floating offshore wind turbine (FOWT) is obviously affected by the motion of the platform, and becomes much more complicated considering the effect of tower shadow. In view of this, this paper aims at investigating the aerodynamic performance of the floating offshore wind turbine with and without a tower under the three most influential motions (surge, pitch and yaw) by computational fluid dynamic (CFD). The results show that the power of the wind turbine is reduced by 1.58% to 2.47% due to the tower shadow effect under the three motions, and the pressure difference distribution is most obviously interfered by the tower shadow effect under yaw motion and concentrates at the root and tip of the blade. In addition, the degree of interference of the tower shadow effect on the wake flow field is different under the three motions, resulting in a more complex wake structure. These conclusions can provide a theoretical basis and technical reference for the o... [more]

The assessment of heating systems is not only interested in the efficiency of the heating system itself, but also in the quality of the environment that the heating system creates. The quality of the environment and the heat-humidity microclimate is closely related to thermal comfort. A suitable environment has a positive effect, for example, on the efficiency of work at the workplace. The range of temperatures, humidity and operating temperatures in workplaces is often also legally prescribed in such a way that there is no thermal discomfort for users in the heated space. In terms of savings, it is therefore best to use heating systems that can create a comfortable environment with the lowest possible energy costs. During their development, variations are possible with temperature gradients, the size of the heat exchange area, or the ratio of the radiant and convective components of heat transfer. When developing such systems, it is appropriate to consider CFD simulations. The compari... [more]

Due to the inadequate pre-dispersion and high dust concentration in the grading zone of the turbo air classifier, a new rotor-type dynamic classifier with air and material entering from the bottom was designed. The effect of the rotor cage structure and diversion cone size on the flow field and classification performance of the laboratory-scale classifier was comparatively analyzed by numerical simulation using ANSYS-Fluent. The grinding process performance with an industrial classifier was also tested on-site. The results revealed that an inverted cone-type rotor cage is more suitable for the under-feed classifier. When the rotor cage’s top-surface diameter to bottom-surface diameter ratio was too large or too small, the radial velocity and tangential velocity at the outer surface of the rotor cage greatly fluctuated. Furthermore, the diameter of the diversion cone also affected the axial velocity and radial velocity of the flow field. Models T-C(1-0.8) and T-D(1-0.7) were determined... [more]

Ethanol is considered as a renewable transport fuels and demand is expected to grow. In this work, trends related to bio-ethanol production are described using Thailand as an example. Developments on high-temperature fermentation and membrane technologies are also explained. This study focuses on the application of membranes in ethanol recovery after fermentation. A preliminary simulation was performed to compare different process configurations to concentrate 10 wt% ethanol to 99.5 wt% using membranes. In addition to the significant energy reduction achieved by replacing azeotropic distillation with membrane dehydration, employing ethanol-selective membranes can further reduce energy demand. Silicalite membrane is a type of membrane showing one of the highest ethanol-selective permeation performances reported today. A silicalite membrane was applied to separate a bio-ethanol solution produced via high-temperature fermentation followed by a single distillation. The influence of contami... [more]

The equivalent continuum method an effective approach for modeling heat transfer in fractured geothermal reservoirs. However, presently there is a lack of systematical and profound study on application conditions of the equivalent porous media (EPM) method. In this study, we numerically investigated the application conditions of the EPM method based on geological data of Yangbajing geothermal field. The results indicate that when fracture spacing is within 3−25 m, the results of the EPM method are basically in the same levels as those of the MINC method. However, when the fracture spacing is within 25−300 m, differences of the EPM method from the MINC method increase with the fracture spacing, so when the fracture spacing is within 25−300 m, it is unreasonable to adopt the EPM method to simulate the fractured reservoirs. With the fracture spacing increasing within 25−300 m, the system production temperature and electric power will gradually decrease; the injection pressure, reservoir i... [more]

Solution blow spinning (SBS) is gaining popularity for producing fibres for smart textiles and energy harvesting due to its operational simplicity and high throughput. The whole SBS process is significantly dependent on the characteristics of the attenuation force, i.e., compressed air. Although variation in the fibre morphology with varying air input pressure has been widely investigated, there is no available literature on the experimentally determined flow characteristics. Here, we have experimentally measured and calculated airflow parameters, namely, output air pressure and velocity in the nozzle wake at 12 different pressure values between 1 and 6 bar and 11 different positions (retracted 5 mm to 30 mm) along the centreline. The results obtained in this work will answer many critical questions about optimum protrusion length for the polymer solution syringe and approximate mean fibre diameter for polyvinylidene fluoride (PVDF) at given output air pressure and velocity. The highes... [more]

The inlet gas void fraction (IGVF) has a great effect on the power performance of the multiphase pump, and the effect is even greater under the cavitation condition. To reveal the effect of the IGVF on the cavitation evolution and the work performance of the multiphase pump at different cavitation stages, the cavitation flow was calculated numerically for the pump under different inlet gas void fractions (IGVFs) of 0%, 10% and 20%. Meanwhile, the numerical simulation method was verified experimentally. The results showed that the increase of the IGVF could improve the cavitation performance of the multiphase pump and inhibit the increasing rate of the vapor. With the aggravation of the cavitation, the output power of the impeller decreased gradually under different IGVFs. In addition, the variation trend of the output power and the net energy gained by the fluid within each domain were exactly the same. At the same time, the position of better work performance was located in the impell... [more]

Wheel braking devices is some of the most widely used landing deceleration devices in modern aircraft. Jet pipe pressure servo valves are widely used in large aircraft wheel brake control systems because of their high anti-pollution ability, high sensitivity and fast dynamic response. However, most brake systems suffer vibration phenomena during the braking process. The pressure servo valve is an important part of the hydraulic brake system, and also an important factor affecting the vibration of the system. In order to solve the vibration problem in the brake system this paper present a two-stage brake pressure servo valve design. We place feedback channels at both ends of the main spool to stabilize the output pressure. In addition, modeling, simulation and experimental verifications are carried out. Firstly, the principle and structure of the pressure servo valve are described. An accurate mathematical model of the two-stage brake pressure servo valve and the testing system is estab... [more]

In this work, single-phase (liquid water) and two-phase (liquid water and gaseous oxygen) 3D-CFD flow analysis of the anode of a high pressure PEM electrolysis cell was conducted. 3D-CFD simulation models of the anode side porous transport layer of a PEM electrolyzer cell were created for the flow analysis. For the geometrical modelling of the PTL, two approaches were used: (a) modelling the exact geometry and (b) modelling a simplified geometry using a porosity model. Before conducting two-phase simulations, the model was validated using a single-phase approach. The Eulerian multiphase and the volume-of-fluid approaches were used for the two-phase modelling and the results were compared. Furthermore, a small section of the PTL was isolated to focus on the gas bubble flow and behaviour in more detail. The results showed plausible tendencies regarding pressure drop, velocity distribution and gas volume fraction distribution. The simplified geometry using the porous model could adequatel... [more]

For the manufacturing of complex biopharmaceuticals using bioreactors with cultivated mammalian cells, high product concentration is an important objective. The phenotype of the cells in a reactor plays an important role. Are clonal cell populations showing high cell-specific growth rates more favorable than cell lines with higher cell-specific productivities or vice versa? Five clonal Chinese hamster ovary cell populations were analyzed based on the data of a 3-month-stability study. We adapted a mechanistic cell culture model to the experimental data of one such clonally derived cell population. Uncertainties and prior knowledge concerning model parameters were considered using Bayesian parameter estimations. This model was used then to define an inoculum train protocol. Based on this, we subsequently simulated the impacts of differences in growth rates (±10%) and production rates (±10% and ±50%) on the overall cultivation time, including making the inoculum train cultures; the final... [more]

Process safety helps prevent the unexpected and unplanned release of flammable and toxic chemicals, leading to poisonous gas clouds, fires, and explosions. Vapor cloud explosions (VCEs) are among the most severe hazards to humans and the environment in process facilities. Therefore, process safety demands to use best and reliable techniques to model VCEs in process industries and storage tanks of flammable chemicals. In this regard, the Computational Fluid Dynamics (CFD) models are more appropriate, as these models provide three-dimensional (3D) modeling of all sequences of events in an accident. In this study, CFD is used to model VCE in two industrial accidents: the Amuay refinery disaster (happened in 2012) and the Indian Oil Corporation’s (IOC) Jaipur terminal (2009). This work studies 3D CFD modeling of flammable cloud explosion in the real-time configuration for both accidents. FLACS (FLame ACceleration Simulator), a CFD software, is used to simulate the loss of hydrocarbon conta... [more]

Gas turbulence modulations and particle dispersions of swirling gas−particle two-phase flow in the combustor is investigated under the large spans of the particle Stokes numbers. To fully consider the preferential concentrations and anisotropic dispersions of a particle, a kinetic frictional stress model coupled with a second-order moment two-phase turbulent model and granular temperature equation is improved. The proposed modeling and simulations are in good agreement with the experimental validations. Results show turbulent modulations and particle dispersions exhibit strongly anisotropic characteristics, keeping a close relationship with flow structure. The axial gas velocity and RMS fluctuation velocity of 45.0-μm EGP was approximately 5.0 times and 3.0 times greater than 1000.0 μm Copper particles, and their axial particle velocity was 0.25 times and twice greater than those of 45.0 μm EGP. The degree of modulation in the axial−radial direction is larger than those of radial−tange... [more]

Detailed process and equipment knowledge is crucial for the successful production of biopharmaceuticals. An essential part is the characterization of equipment for which Computational Fluid Dynamics (CFD) is an important tool. While the steady, Reynolds-averaged Navier−Stokes (RANS) k − ε approach has been extensively reviewed in the literature and may be used for fast equipment characterization in terms of power number determination, transient schemes have to be further investigated and validated to gain more detailed insights into flow patterns because they are the method of choice for mixing time simulations. Due to the availability of commercial solvers, such as M-Star CFD, Lattice Boltzmann simulations have recently become popular in the industry, as they are easy to set up and require relatively low computing power. However, extensive validation studies for transient Lattice Boltzmann Large Eddy Simulations (LB LES) are still missing. In this study, transient LB LES were applied... [more]

Faraday instability is a classic problem that occurs due to the relative displacement of the interface that separates two immiscible fluids placed in a closed container under oscillating acceleration parallel to gravity. The interface deformation and the induced flow patterns of this two-phase flow are very complex and numerical simulations could allow a deeper understanding of the dynamics of these systems. Some tests have been performed to establish a reference solution, but further validation is needed in order to ensure the validity of these solutions. In this work, we compare some numerical solutions for the linear and nonlinear regimes using the phase field scheme with predictions obtained using different numerical schemes such as Front Tracking, Volume of Fluid, and Element-based Finite Volume Method. The results show that, in both linear and nonlinear regimes, some important differences in the prediction of the interface dynamics between the methods are observed, and the need t... [more]

Advancements in internal combustion technology, such as efficiency improvements and the usage of new complex fuels, are often coupled with developments of suitable numerical tools for predicting the complex dynamic behavior of sprays. Therefore, this work presents a Eulerian multi-fluid model specialized for the dynamic behavior of dense evaporating liquid fuel sprays. The introduced model was implemented within the open-source OpenFOAM library, which is constantly gaining popularity in both industrial and academic settings. Therefore, it represents an ideal framework for such development. The presented model employs the classes method and advanced interfacial momentum transfer models. The droplet breakup is considered using the enhanced WAVE breakup model, where the mass taken from the parent droplets is distributed among child classes using a triangular distribution. Furthermore, the complex thermal behavior within the moving droplets is considered using a parabolic temperature profi... [more]

Development of paper industry has been restricted by resources, energy and environment deeply; further reducing energy consumption becomes an urgent problem to be solved. In this paper, the calculating model of steam consumption in bleaching process is established under the premise of ensuring product quality and controlling bleaching cost. Then, an optimization model for minimizing steam consumption is constructed. Compared with before optimization, the steam consumption of the optimized bleaching system reduced by 19.48% (0.5014 t/adt) at a loss of 0.11% brightness (0.1 ISO%) and 5.17% viscosity (33 mL/g). The amount of chemicals should be increased to ensure the quality of the pulp while decreasing the bleaching temperature to reduce steam consumption, the cost of bleaching pulp has decreased by 1.62% (3.19 USD/adt) after optimization. The verification experiments showed all the pulp quality indices can meet the requirements of bleached pulp.

The importance of endodontics is presented within our own concept of Dentistry Sustainable Development (DSD) consisting of three inseparable elements; i.e., Advanced Interventionist Dentistry 4.0 (AID 4.0), Global Dental Prevention (GDP), and the Dentistry Safety System (DSS) as a polemic, with the hypothesis of the need to abandon interventionist dentistry in favour of the domination of dental prevention. In view of the numerous systemic complications of caries that affect 3−5 billion people globally, endodontic treatment effectively counteracts them. Regardless of this, the prevention of oral diseases should be developed very widely, and in many countries dental care should reach the poorest sections of society. The materials and methods of clinical management in endodontic procedures are characterized. The progress in the field of filling materials and techniques for the development and obturation of root canals is presented. The endodontics market is forecast to reach USD 2.1 billi... [more]

The recent decline in crude oil prices due to global competition and COVID-19-related demand issues has highlighted the need for the efficient operation of an oil and gas plant. One such avenue is accurate predictions about the remaining useful life (RUL) of components used in oil and gas plants. A tribosystem is comprised of the surfaces in relative motion and the lubricant between them. Lubricant oils play a significant role in keeping any tribosystem such as bearings and gears working smoothly over the lifetime of the oil and gas plant. The lubricant oil needs replenishment from time to time to avoid component breakdown due to the increased presence of wear debris and friction between the sliding surfaces of bearings and gears. Traditionally, this oil change is carried out at pre-determined times. This paper explored the possibilities of employing machine learning to predict early failure behavior in sensor-instrumented tribosystems. Specifically, deep learning and tribological data... [more]