scholarly journals Flow Dynamic Analysis of Core Shooting Process through Experiment and Multiphase Modeling

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Changjiang Ni ◽  
Gaochun Lu ◽  
Tao Jing ◽  
Junjiao Wu
Keyword(s):  
High Speed ◽  
Volume Fraction ◽  
Solid Phase ◽  
Flow Behavior ◽  
Measuring System ◽  
Frictional Stress ◽  
The Core ◽  
Sand Particles ◽  
Simulation Results ◽  
Core Shooting Process

Core shooting process is the most widely used technique to make sand cores and it plays an important role in the quality of sand cores as well as the manufacture of complicated castings in metal casting industry. In this paper, the flow behavior of sand particles in the core box was investigated synchronously with transparent core box, high-speed camera, and pressure measuring system. The flow pattern of sand particles in the shooting head of the core shooting machine was reproduced with various colored core sand layers. Taking both kinetic and frictional stress into account, a kinetic-frictional constitutive correlation was established to describe the internal momentum transfer in the solid phase. Two-fluid model (TFM) simulations with turbulence model were then performed and good agreement was achieved between the experimental and simulation results on the flow behavior of sand particles in both the shooting head and the core box. Based on the experimental and simulation results, the flow behavior of sand particles in the core box, the formation of “dead zone” in the shooting head, and the effect of drag force were analyzed in terms of sand volume fraction (αs), sand velocity (Vs), and pressure variation (P).

Natural Convection Inside a Bidisperse Porous Medium Enclosure

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
Arunn Narasimhan ◽  
B. V. K. Reddy
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Natural Convection ◽  
Volume Fraction ◽  
Solid Phase ◽  
Darcy Number ◽  
The Core ◽  
Side Walls ◽  
Porous Blocks ◽  
Rayleigh Numbers

Bidisperse porous medium (BDPM) consists of a macroporous medium whose solid phase is replaced with a microporous medium. This study investigates using numerical simulations, steady natural convection inside a square BDPM enclosure made from uniformly spaced, disconnected square porous blocks that form the microporous medium. The side walls are subjected to differential heating, while the top and bottom ones are kept adiabatic. The bidispersion effect is generated by varying the number of blocks (N2), macropore volume fraction (ϕE), and internal Darcy number (DaI) for several enclosure Rayleigh numbers (Ra). Their effect on the BDPM heat transfer (Nu) is investigated. When Ra is fixed, the Nu increases with an increase in both DaI and DaE. At low Ra values, Nu is strongly affected by both DaI and ϕE. When N2 is fixed, at high Ra values, the porous blocks in the core region have negligible effect on the Nu. A correlation is proposed to evaluate the heat transfer from the BDPM enclosure, Nu, as a function of Raϕ, DaE, DaI, and N2. It predicts the numerical results of Nu within ±15% and ±9% in two successive ranges of modified Rayleigh number, RaϕDaE.

An efficient improved routing strategy for multilayer networks

2020 ◽  
pp. 2150078
Author(s):  
Jinlong Ma ◽  
Min Li ◽  
Yaming Li ◽  
Xiangyang Xu ◽  
Weizhan Han ◽  
...  
Keyword(s):  
Multilayer Structure ◽  
High Speed ◽  
Multilayer Networks ◽  
Traffic Dynamics ◽  
The Core ◽  
Transmission Process ◽  
Routing Strategy ◽  
Traffic Capacity ◽  
Average Transmission ◽  
Simulation Results

Traffic dynamics of multilayer networks draws continuous attention from different communities since many systems are actually proved to have a multilayer structure. Since the core nodes of network are prone to congested, an effective routing strategy is of great significance to alleviate the congestion of the multilayer networks. In this paper, we propose an efficient improved routing strategy, with which the core nodes that can reasonably avoid congestion at the high-speed layer in the transmission process of packets, and can also make the most of the traffic resources of the low-speed layer nodes to optimize the traffic capacity of multilayer networks. The simulation results show that the proposed routing strategy can not only improve the network traffic capacity, but also shorten the average path length and average transmission time.

scholarly journals Numerical investigation of turbulent flow behavior of sand particles in core shooting process

2019 ◽  
Vol 37 ◽  
pp. 182-189
Author(s):  
Lele Tong ◽  
Xu Shen ◽  
Jianxin Zhou ◽  
Yajun Yin ◽  
Xiaoyuan Ji
Keyword(s):  
Turbulent Flow ◽  
Numerical Investigation ◽  
Flow Behavior ◽  
Sand Particles ◽  
Core Shooting Process

Experimental Investigation of Volume Fraction in an Annulus Using Electrical Resistance Tomography

SPE Journal ◽  
2019 ◽  
Vol 24 (05) ◽  
pp. 1947-1956 ◽  
Author(s):  
Syed Raza Rehman ◽  
Alap Ali Zahid ◽  
Anwarul Hasan ◽  
Ibrahim Hassan ◽  
Mohammad A. Rahman ◽  
...  
Keyword(s):  
Multiphase Flow ◽  
Electrical Resistance ◽  
High Speed ◽  
Volume Fraction ◽  
Flow Behavior ◽  
Complex Flow ◽  
Flow Loop ◽  
Electrical Resistance Tomography ◽  
Horizontal Drilling ◽  
Hole Cleaning

Summary Horizontal drilling technology has shown to improve the production and cost–effectiveness of the well by generating multiple extraction points from a single vertical well. The efficiency of hole cleaning is reduced because of the solid–cuttings accumulation in the annulus in cases of extended–reach drilling. It is difficult to study the complex flow behavior in a drilling annulus using the existing visualization techniques. In this study, experiments were carried out in the multiphase flow–loop system consisting of a simulated drilling annulus using electrical resistance tomography (ERT) and a high–speed camera. Real–time tomographic images (quantitative visualization) of multiphase flow from ERT were compared to the actual photographs of the flow conditions in a drilling annulus. The quantitative analysis demonstrates that ERT has a wide potential application in studying the hole–cleaning issues in the drilling industry.

Model development and validation of electrospun jet formation

2018 ◽  
Vol 89 (11) ◽  
pp. 2177-2186 ◽  
Author(s):  
Yuansheng Zheng ◽  
Binjie Xin ◽  
Masha Li
Keyword(s):  
High Speed ◽  
Volume Fraction ◽  
Model Development ◽  
Electrospinning Process ◽  
Taylor Cone ◽  
Jet Formation ◽  
Velocity Magnitude ◽  
Key Factor ◽  
Simulation Results ◽  
Development And Validation

The Taylor cone formed at the tip of the syringe used for delivering the solution plays an important role in jet formation. This study presents a novel multiphysics model to simulate the dynamic processes occurring within the cone jet from a flat spinneret and a single needle spinneret. The electric field, volume fraction and velocity magnitude of the polymer jet ejecting from two different kinds of spinnerets are calculated by the multiphysics simulation model. A high-speed camera is employed to capture the jet formed by the Taylor cone. The simulation results are validated by comparison with experimental results. It is found that the spinneret configuration could be the key factor in determining cone morphology in the electrospinning process.

MODELING AND INJURY REPAIR ANALYSIS OF ARTICULAR CARTILAGE BASED ON FIBER CONTENT

2019 ◽  
Vol 19 (08) ◽  
pp. 1940050
Author(s):  
MONAN WANG ◽  
YUANXIN JI ◽  
YUZHENG MA ◽  
JUNTONG JING
Keyword(s):  
Mechanical Properties ◽  
Liquid Phase ◽  
Volume Fraction ◽  
Solid Phase ◽  
Von Mises Stress ◽  
Elastic Model ◽  
Fiber Reinforced ◽  
Element Analysis ◽  
Simulation Results ◽  
Von Mises

It has great guiding significance for the prevention of osteoarthritis and the mechanical state of cartilage after tissue engineering repair to study the relationship between the mechanical properties of cartilage and its structure. This paper considered both the consideration of the solid phase, liquid phase, fiber-reinforced phase in the cartilage and the influence of the contents of major fibers and minor fibers near the cartilage surface. Based on these, a tangential zone of cartilage was established, and a certain improvement and optimization of the fiber-reinforced porous elastic model was performed. The Abaqus software and the Fortran language were used to complete simulation. Simulation results were compared with experiment’s results to verify the validity of the model. Finally, the model was used to perform finite element analysis of different degrees of repairable depth under sliding conditions. Several results were obtained. When the indenter is farther from the interface at the repair site, the mechanical changes in the cartilage are relatively stable. The contact stress of the tangential layer repair and the full-layer repair is small. The volume fraction of the liquid phase in the tangential layer and the full layer repair is lower than that in the other layer regions. The liquid flow rate and the Von Mises stress at the junction of the tangential layer repair are very high. Simulation results were used to explore differences in cartilage mechanical properties of different repairable depths, so as to select the best repairable depth for cartilage.

Design of PCI Express X1 to CPCI Express X1 Adapter

2013 ◽  
Vol 718-720 ◽  
pp. 1262-1267
Author(s):  
Qiang Zhou ◽  
Ming Wang
Keyword(s):  
High Speed ◽  
Signal Integrity ◽  
Clock Signal ◽  
Design And Development ◽  
Pci Express ◽  
The Core ◽  
Simulation Results ◽  
Online Tests

This paper presents the design and development of a PCI Express X1 to CPCI Express X1 adapter which researchers can utilize to test, debug and develop CPCI/PXI Express X1 interface cards in PCI Express X1, X4, X8, X16 slots. The adapter uses Multi-layer Impedance Controlled PCB to precisely control the single-ended and differential impedance of the core high-speed transceiver differential signals and the clock signal. Signal integrity was analyzed by HyperLynx and online tests were verified successfully. The experimental and simulation results demonstrate that the adapter is completely compatible with the interface specifications and the transferred signal is correct and effective.

Three-dimensional computational fluid dynamics investigation of hydrodynamics behaviour of gas–solid flow in fluidized bed of Geldart D particles

2021 ◽  
pp. 095440892098769
Author(s):  
Fazia Aiche ◽  
Salah Belaadi ◽  
Adel Lalaoua ◽  
Abdallah Sofiane Berrouk ◽  
Abdelwahid Azzi
Keyword(s):  
Fluidized Bed ◽  
Gas Flow ◽  
Turbulence Modeling ◽  
Volume Fraction ◽  
Solid Phase ◽  
Fluid Model ◽  
Flow Behavior ◽  
Three Dimensional ◽  
Industrial Processes ◽  
Cyclic Process

Fluidized beds are widely used in many industrial processes as they ensure the desirable high-intensity heat and mass transfers between gas and particles and offer the possibility to perform operations in a continuous mode and powders recycling. Some of these industrial processes use Geldart D type of powders and operate in the slugging mode. This paper presents a 3 D numerical model of gas-solid flows in a fluidized bed based on the Two-Fluid Model (TFM). Turbulence modeling (k- ε) was used to predict flow behavior in fluidized bed of Geldart D particles. The solid phase consists of Geldart D powders and the gas flow is in a slug regime. The numerical results are validated against the experimental work of Azzi et al. Model predictions on flow patterns, bed expansion, volume fraction time series and pressure drop fluctuations are presented and discussed in details in order to demonstrate the cyclic process of slug formation (onset, growth, rising and bursting of slugs) and its effects on the overall performance of beds fluidizing Geldart D type of powders.

A Two-Phase CFD Modeling Approach to Investigate the Flow Characteristics in Radial Flow Moving-Bed Reactors

2014 ◽  
Vol 12 (1) ◽  
pp. 497-512 ◽  
Author(s):  
Fang-Zhi Xiao ◽  
Zheng-Hong Luo
Keyword(s):  
Radial Flow ◽  
Solid Phase ◽  
Flow Behavior ◽  
Flow Characteristics ◽  
Cfd Modeling ◽  
Reactor Model ◽  
Two Phase ◽  
Moving Bed ◽  
Porous Media Model ◽  
Simulation Results

Abstract Based on a complete CFD Eulerian–Eulerian two-fluid approach, a comprehensive three-dimensional (3D) two-phase reactor model was suggested to describe the flow behavior in radial flow moving-bed reactors (RFMBRs). A porous media model was incorporated into the reactor model in order to describe the flow resistance provided by the porous walls of the center and annular pipes. Compared with these previous reactor models, the reactor model considers the solid-phase movement instead of immobilization, which benefits for predicting the formation of cavity practically. The simulation results are agreement with the published experimental data. By employing the verified model, the flow field parameters in the reactors such as pressure drop and flow velocity were obtained. Besides, the simulations were then carried out to investigate the effect of the bed voidage on the flow behavior and to understand the phenomenon of cavity in the RFMBRs. The simulation results showed that both the centripetal and the centrifugal flow configurations have the inhomogeneous flow distribution and the phenomenon of cavity. Furthermore, the inhomogeneous distribution increases with the increase of the bed voidage, whereas the phenomenon of cavity is more obvious with the increase of gas inlet velocity. As a whole, this work provided a realistic modeling and a useful approach for the understanding of RFMBRs.

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