Computer Simulation Of Fluid Flow Research Articles

Concept of Computational Fluid Dynamics Design and Analysis Tool for Food Industry: A Bibliometric

Technology that is currently in demand is CFD. By simulating fluid flow around a product on a computer, the computational fluid dynamics (CFD) technique allows designers of new products to be tested. This research aims to analyze the bibliometrics of CFD publications as a design tool in the food industry to determine concepts, trends, and contributions of previous research. Computational Fluid Dynamics (CFD) is a technology used to test product designs through computer simulations of fluid flow around the product. The use of technology in various industries, such as the food industry, is essential to create better products or services. This research uses a bibliometric analysis method supported by theoretical analysis. This research consists of 5 steps, namely (i) determining the research theme for formulating keywords, (ii) collecting publication documents, (iii) data processing, (iv) bibliometric analysis, and (v) preparing a report. The keywords used in this research are "Computational Fluid Dynamics Design (CFD) in Food Industry." The results of the publication search found a total of 211 documents from 1992 to 2023. The average number of publications was 6.59. The trend of CFD publications in the food industry was first carried out in 1992. The development of this publication has been fluctuating, and there has been an increase in publications in the last five years (2019 - 2023). Research publications regarding CFD in the food industry are grouped into 20 subject areas. Contributions to this research consisted of 159 authors, 160 affiliates, and 51 countries. Completing this research will likely provide information regarding publication sources and contributions made by several scientists from various affiliates and countries worldwide.

A new species of Nanhsiungchelys (Testudines: Cryptodira: Nanhsiungchelyidae) from the Upper Cretaceous of Nanxiong Basin, China.

Nanhsiungchelyidae are a group of large turtles that lived in Asia and North America during the Cretaceous. Here we report a new species of nanhsiungchelyid, Nanhsiungchelys yangi sp. nov., from the Upper Cretaceous of Nanxiong Basin, China. The specimen consists of a well-preserved skull and lower jaw, as well as the anterior parts of the carapace and plastron. The diagnostic features of Nanhsiungchelys include a large entire carapace length (∼55.5 cm), a network of sculptures consisting of pits and ridges on the surface of the skull and shell, shallow cheek emargination and temporal emargination, deep nuchal emargination, and a pair of anterolateral processes on the carapace. However, Nanhsiungchelys yangi differs from the other species of Nanhsiungchelys mainly in having a triangular-shaped snout (in dorsal view) and wide anterolateral processes on the carapace. Additionally, some other characteristics (e.g., the premaxilla is higher than wide, the maxilla is unseen in dorsal views, a small portion of the maxilla extends posterior and ventral of the orbit, and the parietal is bigger than the frontal) are strong evidence to distinguish Nanhsiungchelys yangi from Nanhsiungchelys wuchingensis. A phylogenetic analysis of nanhsiungchelyids places Nanhsiungchelys yangi and Nanhsiungchelys wuchingensis as sister taxa. Nanhsiungchelys yangi and some other nanhsiungchelyids bear distinct anterolateral processes on the carapace, which have not been reported in any extant turtles and may have played a role in protecting the head. The Nanxiong Basin was extremely hot during the Late Cretaceous, and so we suggest that nanhsiungchelyids might have immersed themselves in mud or water to avoid the heat, similar to some extant tortoises. If they were capable of swimming, our computer simulations of fluid flow suggest the anterolateral processes could have reduced drag during locomotion.

Dependence of percolation and flow properties of fracture networks on the morphology

Extensive experimental data have provided evidence that rock fractures have finite widths, and that their length is typically distributed according to some probability distribution function (PDF). Almost all the past modeling and computer simulation of fluid flow through fracture networks assumed that the fractures’ width is vanishingly small, and their length is constant. Using extensive Monte Carlo simulation and a model in which the fractures have a finite width and their length follows a PDF, we study the effect of the PDF on the effective permeability, the mean porosity, the excluded volume (area), and the percolation threshold of the network. Five PDFs of the fractures’ lengths, namely, uniform, Gaussian, log-normal, exponential, and power law, are considered, and their effect on the aforementioned properties of the fracture networks is studied. If the distributions are narrow, their effect on the properties of the fracture network is not strong. The effect is, however, quite strong when the PDFs are broad, which is also what experimental data indicate. Both the mean porosity and effective permeability depend on the fracture density as power laws, with exponents that are nonuniversal and depend on the width of the PDF, in agreement with many sets of experimental data reported in the literature.

Numerical simulation of upwinding schemes applied to complex fluid dynamics equations

In this work, the nonlinear Euler equations of gas dynamics are employed for a comparative study of the frequently used flux limiters, namely: the consecrated ARORA-ROE, van Albada, CUBISTA and ADBQUICKEST; and two rational functions TVD-CBC-based TOPUS and SDPUS-C1 schemes. The comparison is mainly done in terms of their abilities in resolving discontinuities, reproducing complex flow phenomena and accuracy. It is concluded that both TOPUS and SDPUS-C1 can be considered as alternative tools for computer simulations of fluid flow. As application, the corresponding SDPUS-C1 scheme is employed to simulate 2D/3D incompressible flows with moving free surfaces.

Validated model of platelet slip at stenosis and device surfaces

Platelets are central to thrombosis. However, it is unknown whether platelets slip at vascular or device surfaces. The presence of platelet slip at a surface would interrupt physical contact between the platelet and that surface, and therefore diminish adhesion and thrombosis. Unfortunately, no existing technology can directly measure platelet slip in a biological environment. The objective of this study was to explore whether microspheres–modeling platelets–slip at different vascular and device surfaces in an acrylic scaled-up model coronary artery. The microspheres (3.12 µm diameter) were suspended in a transparent glycerol/water experimental fluid, which flowed continuously at Reynolds numbers typical of coronary flow (200–400) through the model artery. We placed a series of axisymmetric acrylic stenoses (cross-sectional area reduction [CSAr], 20–90%) into the model artery, both without and with a central cylinder present (modeling a percutaneous interventional guide wire, and with a scaled-up Doppler catheter mounted upstream). We used laser Doppler velocimetry (LDV) to measure microsphere velocities within, proximal and distal to each stenosis, and compared to computer simulations of fluid flow with no-slip. For validation, we replaced the acrylic with paraffin stenoses (more biologically relevant from a surface roughness perspective) and then analyzed the signal recorded by the scaled-up Doppler catheter. Using the LDV, we identified progressive microsphere slip proportional to CSAr inside entrances for stenoses ≥60% and ≥40% without and with cylinder present, respectively. Additionally, microsphere slip occurred universally along the cylinder surface. Computer simulations indicated increased fluid shear rates (velocity gradients) at these particular locations, and logistic regression analysis comparing microsphere slip with fluid shear rate resulted in a c-index of 0.989 at a cut-point fluid shear rate of (10.61 [cm−1]×mean velocity [cm×sec−1]). Moreover, the presence of the cylinder caused disordering of microsphere shear rates distal to higher grade stenoses, indicating a disturbance in their flow. Finally, despite lower precision, the signal recorded by the scaled-up Doppler catheter nonetheless indicated slip at the entry into and at most locations distal to the 90% stenosis. Our validated model establishes proof of concept for platelet slip, and platelet slip explains several important basic and clinical observations. If technological advances allow confirmation in a true biologic environment, then our results will likely influence the development of shear-dependent antiplatelet drugs. Also, adding shear rate information, our results provide a direct experimental fluid dynamic foundation for antiplatelet-focused antithrombotic therapy during coronary interventions directed towards higher grade atherosclerotic stenoses.

Laboratory investigation of asphaltene-induced formation damage

The purpose of this study is to evaluate the degree of formation damage caused by asphaltene deposition in the pore throats in case of oilfield operation. Many wells in the Samara region oilfields are operated under high reservoir drawdown, with downhole pressure lower than the bubble point. Such wells’ operating conditions lead to a change in oil composition (light components are extracted from oil while asphaltenes are precipitated and deposited) in the near wellbore, and the productivity of the wells declines due to asphaltene deposition. The study procedure presented in the paper included the following methods: high-pressure microscopy with grain size analysis (the visual method), the near infrared light scattering method and the gravimetric method to measure asphaltenes onset pressure in oil. Formation damage was measured by the filtration method. Asphaltene concentration in oil after filtration was measured by the photocolorimetric analysis. Microcomputed tomography of the core sample was provided to visualize formation damage. In addition, fluid flow in the pore space was simulated before and after asphaltene deposition using a dynamic simulator. In the paper, reservoir oil of one of the Russian oilfields was investigated. The main results of this paper are the following: asphaltene onset pressure in oil at the reservoir temperature (48 °C) was measured as equal to 6.8 MPa which is slightly higher than the bubble-point (6.5 MPa). Oil was flowed through the core sample of the field at three different specific backpressures (at constant flow rate) and formation damage was estimated. The studies have shown that decrease in permeability of the core is caused by asphaltene deposition in the pore space. In this case, a decrease in the amount of asphaltenes in oil emerging from the core sample is observed which was proved by the spectrophotometric analysis. Via microcomputed tomography, a 3D model of the rock matrix and the pore space of the initial and damaged core sample was constructed and a decrease in porosity after formation damage was estimated. Based on the obtained 3D model of the core, computer simulation of fluid flow (in a dynamic simulator) in the initial and damaged core was performed, and the flow parameters (velocity and streamlines) were calculated. The proposed methodology including a set of physical methods to study a core before and after formation damage combined with fluid flow simulation enables predicting potential complications under the field operation.

Computer simulations of fluid flow over catalytic surfaces for water splitting

Interfacial phenomena arising at solid/fluid interfaces depend upon the nanoscale structural and dynamical properties of the system. The presence of active sites on the solid surface that can bind with reactants in the fluid enables the investigation of reaction kinetics and its effect on multi-scale transport processes. We develop a coarse-grained particle-based model of the flow of reactants over a solid surface composed of close packed particles with embedded active sites. We investigate the role of the adsorption of the reactants onto these sites on the transport phenomena via the coarse-grained molecular dynamics technique. Our objective is to understand the role of nanoscale interfacial phenomena on the structural and dynamical properties of the system through the measurement of diffusion coefficients, velocity profiles, radial distribution functions, and mean residence times. We have investigated these properties as a function of the active site density, coarse graining effects and interaction strengths. Our results can potentially be used for future studies on multi-scale phenomena driven by reaction kinetics at solid/fluid interfaces, such as artificial photosynthesis cells.

Computer simulations of fluid flow in sediment: From images to permeability

Permeability, unlike porosity, saturation, and lithology, is, arguably, impossible to infer from well data. Yet, it is the key parameter in reservoir simulation and also in well completion and stimulation decisions. The traditional method of obtaining permeability is in the physical laboratory where a pressure difference (ΔP) is applied to the opposite sides of a regularly shaped rock sample and the volumetric flux (Q) of the fluid is measured.

Computer Simulation of Fluid Flow, Heat Transfer for the Production of Cu Thin Wire by OCC Process

In the present study, the fluid flow and the heat transfer with solidification analyses for the Cu thin wire production by OCC (Ohno Continuous Casting) process. The OCC process is widely used to produce cylindrical column castings continuously, a number of researches have been focused on the OCC process. However, few researches on the production of Cu thin wire by the OCC process have been reported, therefore it is necessary to investigate and optimize the process variables of the OCC process when producing the Cu thin wires. A commercial multiphysics software was used to analyse to the flow pattern and the temperature distribution in the OCC system proposed in the present study. Effect of the casting speed, the OCC mold temperature, the melt temperature on the castablility of the thin Cu wire and flow pattern and temperature distribution of the melt were discussed. It is expected that the present study is able to give the design parameters of the OCC system for production of Cu thin wire before the actual OCC system construction.

遠心分離機による微粒子の分級とその流動解析

This study provides fundamental knowledge on the centrifugal classification of liquid-borne particles. It is found that the cut size of a centrifugal separator decreases as the rotational speed increases and the liquid flow rate decreases. Comparing our experimental data with the theory, they agree with each other in the case of a high liquid flow rate. However, the difference between them is significant in the case of a low liquid flow rate. This is because dead spaces are generated in the centrifugal separator at the low liquid flow rate. The computer simulation of fluid flow in the centrifugal separator shows a decrease in velocity near the wall at a low liquid flow rate, suggesting the possibility of formation of dead spaces.

Computer simulations of fluid flow and heat transfer in metal strip heating zone crystal growth

In conventional floating zone crystal growth, convection, especially Marangoni convection in the melt zone, is very strong. In addition, the quality and shape of the crystal is poor and difficult to control. In view of these problems, a modified floating zone crystal growth has been developed, in which a metal strip is immersed in the melt zone. The purpose of this paper is to simulate the fluid flow and the heat transfer during crystal growth, so that this modified process can be understood better. The flow patterns and temperature fields were calculated for the growth of NaNO 3 and Si.

Internal combustion engine design on IBM platforms

Computer simulation of fluid flow and combustion in diesel engines is rapidly gaining an increasing popularity within the automotive industry, becoming recognized as a cost-effective tool for cutting design cycle time. This paper shows how an advanced computing environment for numerically intensive applications, entirely based upon IBM platforms, can be profitably exploited within the framework of a joint project with industrial partners, in this case Renault Vehicules Industriels. The computing environment has been applied to the code KIVA-II, a computer program for numerical combustion developed at Los Alamos National Laboratory. Numerical simulations have been performed to assess the capability of the code to correctly reproduce the experimental data. Several features, such as visualization of the fuel spray droplet formation and its evolution in time, and selected scalar fields (velocity components, temperature, and vapor concentration), have proved invaluable for a correct understanding of the various phenomena under examination. In particular, the scientific data visualizer, combined with the power of cooperative processing, has allowed a rapid identification of the most significant parameters that need to be tuned in order to recover good agreement between the simulation and the experimental data.

Transport of fluid and electric current through a single fracture

One expects the hydraulic and electrical conductivities of rock to be related, since there is an analogy between the differential equations describing each process. Fractures in rock are commonly described by the parallel plate model, where the fracture surfaces are smooth and parallel with a separation or aperture of d. For this model the hydraulic conductivity is proportional to d3, whereas the electrical conductivity is proportional to d. Deviations from the parallel plate model are expected, since real fracture surfaces are rough and in partial contact. Computer simulations of fluid flow and conduction of electricity were performed on simulated fractures composed of rough surfaces generated with a fractal algorithm. The finite difference method was used to calculate the volume flow rate and electric current. This solution was used in the parallel plate model to get an effective hydraulic aperture dh and electric aperture de. The electric and hydraulic apertures are nearly the same when the surfaces are widely separated. However, de is always smaller than dh, with the difference increasing as the fracture closes. Additionally, the local directions of fluid flow and electric current are not the same. Thus contrary to the common assumption, the actual path length of a fluid particle as measured by the tortuosity is different for each process. The results of these simulations are consistent with the “equivalent channel model,” which shows that by introducing the tortuosity of the fluid flow or electric current paths, one can relate the microscopic physics of the transport properties to the macroscopic behaviors described by Darcy's and Ohm's laws.