scholarly journals Parameters in Multiphase Flowing of Natural Gas NGH Slurry via Vertical Pipe

2016 ◽  
Vol 2016 ◽  
pp. 1-7
Author(s):  
Dai Maolin ◽  
Wu Kaisong
Keyword(s):  
Pressure Drop ◽  
Natural Gas ◽  
Simulation Model ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Solid Particles ◽  
Small Scale ◽  
Vertical Pipe ◽  
Particle Volume ◽  
The Relationship

In recent years, the pipeline flowing of natural gas hydrate (hereinafter NGH) slurry has been a promising technique of multiphase flowing via pipe and that of crushed hydrate mixture slurry is also a key technique in solid fluidization mining method of nondiagenetic NGH reservoir below the seabed. In this paper, by using similarity rules, a small-scale simulation model was established to shorten the calculation time. The correctness of the simulation model has been verified through comparison with experiment. Thereby, the distribution of velocity and volume fraction of each phase in the vertical pipe was obtained, and the prototype of vertical pipe was analyzed. By study on the pipe resistance, the pressure drop of slurry, when flowing in vertical pipe, could be calculated asΔP=ρgh+0.23Cρv1.8. In the end, by adjusting volume fraction of particles in the mixture slurry, the relationship between the solid particles’ volume fraction and piezometric pressure drop was obtained. When the optimal flow velocity of the slurry is 2 m/s and the ratio of NGH volume fraction to that of sand is 4 : 1, the optimal particle volume fraction ranges from 20% to 40%.

Constructal Design of Particle Volume Fraction in Nanofluids

2009 ◽  
Vol 131 (11) ◽  
Author(s):  
Chao Bai ◽  
Liqiu Wang
Keyword(s):  
Thermal Resistance ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Circular Disk ◽  
Small Scale ◽  
Particle Volume ◽  
Constructal Design ◽  
Dispersed Particles ◽  
Overall Resistance ◽  
Plane Slab

Abstract We perform a constructal design of particle volume fraction of four types of nanofluids used for heat conduction in four systems: a circular disk, a sphere, a plane slab, and a circular annulus. The constructal volume fraction is obtained to minimize system overall temperature difference and overall thermal resistance. Also included are the features of the constructal volume fraction and the corresponding constructal thermal resistance, which is the minimal overall resistance to the heat flow. The constructal nanofluids that maximize the system performance are not necessarily the ones with uniformly dispersed particles in base fluids. Nanofluids research and development should thus focus on not only nanofluids but also systems that use them. The march toward micro- and nanoscales must also be with the sobering reminder that useful devices are always macroscopic, and that larger and larger numbers of small-scale components must be assembled and connected by flows that keep them alive.

Computer Simulation Model for Spherical Particle Filled Composite Materials

2011 ◽  
Vol 474-476 ◽  
pp. 7-10 ◽  
Author(s):  
Zhuo Chen ◽  
Zhi Xiong Huang ◽  
Ming Zhang ◽  
Min Xian Shi ◽  
Yan Qin ◽  
...  
Keyword(s):  
Computer Simulation ◽  
Composite Materials ◽  
Simulation Model ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Spherical Particles ◽  
Computer Simulation Model ◽  
Particle Volume ◽  
Minimal Sphere ◽  
Center Density

This paper introduced a computer simulation model for composite materials which was reinforced by spherical particles. We introduced its algorithm and visualize the model with different particle volume fraction. In order to evaluate the uniformity of the particle distribution, we estimated Particle Center Density and standard deviation of minimal sphere distance.

Vortex Simulation for Behavior of Solid Particles Falling in Air

2011 ◽  
Author(s):  
Hisanori Yagami ◽  
Tomomi Uchiyama
Keyword(s):  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Air Flow ◽  
Three Dimensional ◽  
Particle Diameter ◽  
Vortex Method ◽  
Solid Particles ◽  
Particle Volume ◽  
Two Phase ◽  
Spherical Region

The behavior of small solid particles falling in an unbounded air is simulated. The particles, initially arranged within a spherical region in a quiescent air, are made to fall, and their fall induces the air flow around them, resulting in the gas-particle two-phase flow. The particle diameter and density are 1 mm and 7.7 kg/m3 respectively. A three-dimensional vortex method proposed by one of the authors is applied. The simulation demonstrates that the particles are accelerated by the induced downward air flow just after the commencement of their fall. It also highlights that the particles are whirled up by a vortex ring produced around the downward air flow after the acceleration. The effect of the particle volume fraction at the commencement of the fall is also explored.

The Effect of Using Nanofluids on Triangular Microchannel Heat Exchanger Performance

2010 ◽  
Author(s):  
G. Bhaskaran ◽  
H. A. Mohammed ◽  
N. H. Shuaib
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Volume Fraction ◽  
Numerical Study ◽  
Particle Volume Fraction ◽  
Three Dimensional ◽  
Hydrodynamic Performance ◽  
Particle Volume ◽  
Microchannel Heat Exchanger

A numerical study is performed to study the effects of using various types of nanofluids on a triangular shaped microchannel heat exchanger (MCHE). The performance of an aluminum MCHE with various types of nanofluids such as Al2O3, CuO, SiO2, Ag and TiO2 and diamond particles with particle volume fraction of 2% using water as base fluid is comprehensively analyzed. The three-dimensional steady, laminar developing flow and conjugate heat transfer of a balanced MCHE were solved using finite volume method. In order to maintain laminar flow in the microchannels, Re number was ranged from 100 to 800. The other parameters tested in this study include the effects of Reynolds number towards the temperature, effectiveness and pressure drop of the MCHE. It is found that nanofluids have improved the temperature profile and heat transfer rate of the MCHE. The increase in pressure drop was minimal while the thermal and hydrodynamic performance of the heat exchanger was enhanced.

Existence and uniqueness of normal shock waves in gas-particle mixtures

1969 ◽  
Vol 38 (3) ◽  
pp. 633-655 ◽  
Author(s):  
Barbara Schmitt-Von Schubert
Keyword(s):  
Shock Waves ◽  
Existence And Uniqueness ◽  
Constant Velocity ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Solid Particles ◽  
Equilibrium Flow ◽  
Particle Volume ◽  
Flow Parameters ◽  
Finite Particle

A mixture of a gas and small solid particles is considered which, far upstream, is in a constant equilibrium state, and moves with a constant velocity. The existence of shock waves is investigated in the four possible cases, namely for frozen flow, for two kinds of partly frozen flow, and for equilibrium flow. It is shown that, in all these cases, compressive shocks may exist, if the upstream velocity exceeds the velocity of sound appropriate to the type of flow. Rarefaction shocks are impossible in each case. Moreover, it is shown that the downstream values of the flow parameters are determined uniquely, and the direction of their change is given. Only rather general assumptions concerning the behaviour of the gas are needed. The paper takes into account the influence of the finite particle volume fraction unlike most previous papers on the topic.

Effects of Initial Perturbations in the Early Moments of an Explosive Dispersal of Particles

2016 ◽  
Vol 138 (7) ◽  
Author(s):  
Subramanian Annamalai ◽  
Bertrand Rollin ◽  
Frederick Ouellet ◽  
Christopher Neal ◽  
Thomas L. Jackson ◽  
...  
Keyword(s):  
Gas Phase ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
High Energy ◽  
Solid Particles ◽  
Dense Layer ◽  
Initial Particle ◽  
Particle Volume ◽  
Reactive Material ◽  
Explosive Dispersal

Recent experiments have shown that when a dense layer of solid particles surrounding a high-energy reactive material is explosively dispersed, the particles cluster locally leading to jetlike patterns. The formation of these coherent structures has yet to be fully understood and is believed to have its origin in the early moments of the explosive dispersal. This paper focuses on the early moments of an explosive dispersal of particles. In particular, the effect of initial perturbations on both the gas and particulate phase is investigated, considering heavy particles with a low initial particle volume fraction. Two-dimensional simulations are carried out, and results suggest that a distinctive heterogeneity in the form of a single wavelength perturbation in the rapidly expanding detonation products does not have a significant impact on the early evolution of neither the gas phase nor the cloud of particles. In contrast, the equivalent distinctive heterogeneity in the initial particle volume fraction distribution lingers for the duration of our simulations. Developing instabilities in the gas phase and at the inner- and outer-most front of the particle bed display a dominant wavelength equal to the wavelength of the initial perturbation in the particle volume fraction.

Development and Validation of Two-Way Fluid-Particle Coupling in Turbulent Flows for a CFD Code

2013 ◽  
Author(s):  
Jianjun Xiao ◽  
Anatoly Svishchev ◽  
Thomas Jordan
Keyword(s):  
Experimental Data ◽  
Turbulent Flows ◽  
Gas Flow ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Continuous Phase ◽  
Particle Dispersion ◽  
Solid Particles ◽  
Particle Volume ◽  
Discrete Phase

A Lagrangian approach was used in CFD code GASFLOW to describe particle dispersion in turbulent flows. One-way coupling between fluid and particle is often used due to its simplicity of implementation. However, in case of higher particle volume fraction or mass loading in the continuous phase, one-way coupling is not sufficient to simulate the interaction between fluid and particles. For instance, the liquid droplets released by a spray nozzle in the nuclear power plant will lead to a strong gas entrainment, and consequently impact the gas flow field. When the volume fraction of the discrete phase is not negligible compared to the continuous phase, the interaction between the continuous fluid and dispersed phase becomes significant. Two-way momentum coupling between fluid and solid particles was developed in CFD code GASFLOW. The dynamics of the discrete particles was solved by an implicit algorithm to ensure the numerical stability. The contribution of all particles to a fluid cell was treated as the source term to the continuous phase which was solved with Arbitrary-Lagrangian-Eulerian (ALE) methodology. In order to verify and validate the code, the calculation results were then compared to theoretical results, predictions of other CFD codes and experimental data. Predictions compared favorably with the experimental data. It indicates that the effect of two-way coupling is significant when the volume fraction of discrete phase is not negligible. Two-way coupling of mass, energy and turbulence will be implemented in the future development of the GASFLOW code.

Computer Simulation Model for Multi-Size Spherical Particles Reinforced Composite Materials

2012 ◽  
Vol 508 ◽  
pp. 361-364 ◽  
Author(s):  
Zhuo Chen ◽  
Zhi Xiong Huang ◽  
Rong Yang Dou ◽  
Jing Dai ◽  
Min Xian Shi ◽  
...  
Keyword(s):  
Computer Simulation ◽  
Composite Materials ◽  
Simulation Model ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Spherical Particles ◽  
Computer Simulation Model ◽  
Particle Volume ◽  
Reinforced Composite ◽  
The Matrix

In this Research a Method for Computer Simulation Model of Composite Materials, which Are Reinforced by Multi-Size Particles, Is Introduced. All Particles Are Embedded in the Matrix Randomly. Composite of Different Particle Volume Fraction Were Simulated and Visualized. Statistic Results Shows that the Particles Disperse Distribution Are Uniform which Could Be Used in the Further Study of Composite.

Numerical study of heat transfer and Hall current impact on peristaltic propulsion of particle-fluid suspension with compliant wall properties

2019 ◽  
Vol 33 (35) ◽  
pp. 1950439 ◽  
Author(s):  
M. M. Bhatti ◽  
Rahmat Ellahi ◽  
A. Zeeshan ◽  
M. Marin ◽  
N. Ijaz
Keyword(s):  
Heat Transfer ◽  
Volume Fraction ◽  
Hall Current ◽  
Numerical Study ◽  
Nonlinear Differential Equations ◽  
Particle Volume Fraction ◽  
Mathematical Formulation ◽  
Solid Particles ◽  
Particle Volume ◽  
The Impact

In this paper, the effects of heat transfer and Hall current on the sinusoidal motion of solid particles through a planar channel has been discussed. The walls of the channel are considered as compliant under the effects of magnetohydrodynamics. The mathematical formulation has been performed using energy equation, momentum equation, and Ohm’s law. The modeled equations are further modified by taking the assumption of a zero Reynolds number and long wavelength. Numerical shooting technique has been employed to solve the nonlinear differential equations. The impact of all the emerging parameters such as wall rigidity, wall tension, mass characterization, Hall parameter, Hartmann number, Weissenberg number, particle volume fraction, Prandtl number, and Eckert number, respectively. Particularly, we discussed their effects on velocity and temperature profile.

Experimental Investigation of Freezing Behavior of Melt/Solid Particles Mixture on to Metal Structure

2010 ◽  
Author(s):  
Md. Abdul Malek Soner ◽  
Shunichi Seo ◽  
Yu Hasegawa ◽  
Yusuke Himuro ◽  
Koji Morita ◽  
...  
Keyword(s):  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Thermal Conditions ◽  
Metal Structure ◽  
Video Camera ◽  
Solid Particles ◽  
Particle Volume ◽  
Penetration Length ◽  
Solid Mixture ◽  
Penetration Behavior

The freezing and penetration of molten core fuel and structural materials penetrating into flow channels are important thermal-hydraulics phenomena to safety assessment of postulated core disruptive accidents in liquid metal reactors. The main objective of this study is to investigate fundamental characteristics of freezing and penetration behavior involved in melt and solid mixture flowing on-to structure material. In our study, solid copper particles mixed with molten wood’s metal (melting point 78.8°C) was used as a simulant melt, while stainless steel and brass were used as freezing structures. A series of fundamental experiments was performed to study the effects of solid particles on the freezing and penetration behavior under the various thermal conditions of molten metal and varying solid particle volume fraction and structure metal. The melt flow and distribution were observed using a digital video camera. The melt penetration length on the structure and proportion of adhered frozen metal on to structure surfaces were measured in the present series of experiments. The results indicate that penetration length becomes shorter with increasing solid particles volume fraction in melt. The present results will be utilized to build a relevant database for verification of fast reactor safety analysis codes.

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