scholarly journals Numerical Simulation of Turbopump Inducer Cavitating Behavior

2005 ◽  
Vol 2005 (2) ◽  
pp. 135-142 ◽  
Author(s):  
O. Coutier-Delgosha ◽  
P. Morel ◽  
R. Fortes-Patella ◽  
JL. Reboud
Keyword(s):  
Numerical Simulation ◽  
Spatial Distribution ◽  
Numerical Model ◽  
Complex Geometry ◽  
Numerical Results ◽  
Cavitating Flows ◽  
Flow Conditions ◽  
And Performance

In the present study a numerical model of 3D cavitating flows is proposed. It is applied to investigate the behavior of a spatial turbopump inducer in noncavitating and cavitating conditions. Experimental and numerical results concerning inducer characteristics and performance breakdown are compared at different flow conditions. The cavitation development and the spatial distribution of vapor structures within the inducer are also analyzed. The results show the ability of the code to simulate the quasi-steady cavitating behavior of such a complex geometry. Discrepancies concerning the breakdown prediction are also discussed.

scholarly journals Experimental and Numerical Studies in a Centrifugal Pump With Two-Dimensional Curved Blades in Cavitating Condition

2003 ◽  
Vol 125 (6) ◽  
pp. 970-978 ◽  
Author(s):  
O. Coutier-Delgosha ◽  
R. Fortes-Patella ◽  
J. L. Reboud ◽  
M. Hofmann ◽  
B. Stoffel
Keyword(s):  
Spatial Distribution ◽  
Numerical Model ◽  
Three Dimensional ◽  
Rotating Machinery ◽  
Two Dimensional ◽  
Special Test ◽  
Cavitating Flows ◽  
Flow Conditions ◽  
Numerical Studies ◽  
And Performance

In the presented study a special test pump with two-dimensional curvature blade geometry was investigated in cavitating and noncavitating conditions using different experimental techniques and a three-dimensional numerical model implemented to study cavitating flows. Experimental and numerical results concerning pump characteristics and performance breakdown were compared at different flow conditions. Appearing types of cavitation and the spatial distribution of vapor structures within the impeller were also analyzed. These results show the ability of the model to simulate the complex three-dimensional development of cavitation in a rotating machinery, and the associated effects on the performance.

Numerical Simulation of Droplet Ejection Based on VOF Method

2014 ◽  
Vol 548-549 ◽  
pp. 1257-1264 ◽  
Author(s):  
Xiao Yong Suo
Keyword(s):  
Numerical Simulation ◽  
Surface Tension ◽  
Numerical Model ◽  
Physical Properties ◽  
Vof Method ◽  
Numerical Results ◽  
Droplet Ejection ◽  
Ejection Process ◽  
Ink Jet ◽  
Jet Nozzle

Taking ejection process of the ink droplets from ink-jet nozzle as the prototype, a similar numerical model of droplet ejection was established. The VOF method was applied to track the interface of droplet ejection process and it is shown that the numerical results simulated by the VOF method were accurate and reliable. Six kinds of liquid with different physical properties were chosen as the research object. The numerical results were analyzed and compared. Finally, the effect of the surface tension, viscosity and density on the droplet ejection process was discussed.

Numerical Simulation of Dynamic Compaction at Dredger Fill Silty

2012 ◽  
Vol 446-449 ◽  
pp. 1813-1816
Author(s):  
Yang Liu ◽  
Duo Zhang
Keyword(s):  
Numerical Simulation ◽  
Numerical Model ◽  
Current Practice ◽  
Field Trials ◽  
Past Experience ◽  
Numerical Results ◽  
Dynamic Compaction ◽  
Empirical Equations ◽  
Dredger Fill

Current practice of Dynamic compaction (D.C) depends mainly on field trials, past experience, and empirical equations based on reported records. In this paper, a numerical model is used to study the effectiveness of supplemental drains on densification of saturated dredger fill silty deposits during D.C. Typical numerical results are discussed using propose numerical model.

scholarly journals Three-Dimension Numerical Simulation of Scour Temporal Changes due to Flow in the Downstream of Combined Weirs and Gate Model

2017 ◽  
Vol 3 (11) ◽  
pp. 1111 ◽  
Author(s):  
Yaser Sadeghi Googheri ◽  
Mojtaba Saneie ◽  
Sirous Ershadi
Keyword(s):  
Numerical Simulation ◽  
Energy Dissipation ◽  
Numerical Model ◽  
Three Dimensional ◽  
Turbulent Energy ◽  
Temporal Changes ◽  
Three Dimension ◽  
Flow Conditions ◽  
Scour Hole ◽  
Static Water

Most of weirs create a region with relatively static water in upstream, which can be the place of sediments and wastes deposition in water. Sediments accumulation in upstream changes flow conditions.  In this case, combined weir and gate can be propounded as a useful solution. In the present paper, Flow3D was used to numerically simulate temporal changes of scour in combined free flow over weirs and below gates. Numerical modeling was run after fully preparing and the obtained data was analyzed under three-dimensional conditions. Comparing experimental and numerical results with data fitness revealed that determination coefficient (R2) of the numerical model results to the experimental model results is 0.94. Also, it was found that the relative error of the numerical model results relative to the experimental results equals 7.36%. Further, it was found that at the start of computations in the numerical model, compared to the end of running the model, the turbulent energy dissipation was decreased to 38% and decreasing the turbulent energy dissipation led to the creation of scour hole balance in the numerical model.

scholarly journals Analysis of the sliding mechanics of NBR thread pattern

2021 ◽  
Author(s):  
Roberto Spina ◽  
Luigi Maria Galantucci ◽  
Fulvio Lavecchia ◽  
Bruno Cavalcante ◽  
Thiago Doca ◽  
...  
Keyword(s):  
Numerical Model ◽  
Contact Pressure ◽  
Tangential Force ◽  
Numerical Results ◽  
Vertical Stress ◽  
Experimental Procedure ◽  
Materials Properties ◽  
Study Materials ◽  
And Performance ◽  
Sliding Mechanics

The objective of the present work is to study materials properties and performance of the footwear thread to develop and implement an analytical-numerical model capable of simulating their performance. The numerical results simulation was carried out, analyzing the sliding mechanisms of shoe-floor and evaluating the contact pressure and vertical stress. An experimental procedure, supported by a numerical model, was implemented for computing the evolution of the tangential force over several load increments.

Numerical simulation of dam-break mudflow based on the Herschel-Bulkley model

2021 ◽  
Author(s):  
jinbo Tang ◽  
Peng Cui ◽  
Jiangang Chen
Keyword(s):  
Numerical Simulation ◽  
Numerical Model ◽  
Laboratory Experiments ◽  
Fine Particles ◽  
Shear Thinning ◽  
Numerical Results ◽  
Dam Break ◽  
Navier Stokes Equation ◽  
Study Laboratory ◽  
The Impact

<p>Mudflow behaves normally the flowing properties of viscoplastic or pseudo-plastic stemming from flocculent network structures formed by fine particles within the mud. In order to obtain the dynamical characteristics of the dam-break of mudflow, a numerical model has been developed in the present study. The numerical model solved the Navier-Stokes equation with the Herschel-Bulkley model, which exhibits a plastic properties of fluid with shear-thinning. The two-step projection method are employed to solve the velocity field in present numerical model, and the Bi-CGSTAB technique are implemented to solve the pressure Poisson equation. The volume of fluid (VOF) method is used to track the broken the free surface. In this study, the numerical simulation of dam-break with Herschel-Bulkley fluid are implemented, the numerical results agree well with the other numerical results. Furthermore, when the shear-thinning index is equals to unity, the Herschel-Bulkley model becomes Bingham model. In this study, laboratory experiments of dam-break of slurry in the flume have been conducted to record data with time of the surface height of mudflow and pressure in the bottom of flume. The same cases with laboratory experiments are implemented in our numerical model, the numerical results match with the laboratory experiments. Finally, as a demonstration, the impact of mudflow on the structures   are simulated and discussed.</p>

Study on the Flow Characteristics of Rope and Cylinder With Large-Eddy Simulation

2018 ◽  
Author(s):  
Hui Cheng ◽  
Liuyi Huang ◽  
Yi Ni ◽  
Fenfang Zhao ◽  
Xinxin Wang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Numerical Model ◽  
Large Eddy Simulation ◽  
Flow Characteristics ◽  
Numerical Results ◽  
Hydrodynamic Characteristics ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Smooth Cylinder ◽  
Force Calculation

Three-strand rope is the dominant material in fishing net and fish cage. Smooth cylinder is a common numerical model of net twines in the drag force calculation. This paper studied the hydrodynamic characteristics of ropes and smooth cylinders. Large Eddy Simulation was applied to the numerical simulation. Numerical results indicated that the drag coefficient of rope was much smaller than that of smooth cylinder when Re = 3900. The detailed analysis and comparison of their flow characteristics explained the reason. The specific of eddy shedding and wake pattern were presented in the numerical results.

Modeling of mass transfer in biofilms in oscillatory flow conditions using k-ɛ turbulence model

2003 ◽  
Vol 3 (1-2) ◽  
pp. 201-207
Author(s):  
H. Nagaoka ◽  
T. Nakano ◽  
D. Akimoto
Keyword(s):  
Numerical Simulation ◽  
Mass Transfer ◽  
Turbulence Model ◽  
Uptake Rate ◽  
Oscillatory Flow ◽  
Substrate Uptake ◽  
Flow Conditions ◽  
Mass Transfer Mechanism ◽  
Substrate Uptake Rate ◽  
Good Agreement

The objective of this research is to investigate mass transfer mechanism in biofilms under oscillatory flow conditions. Numerical simulation of turbulence near a biofilm was conducted using the low Reynold’s number k-ɛ turbulence model. Substrate transfer in biofilms under oscillatory flow conditions was assumed to be carried out by turbulent diffusion caused by fluid movement and substrate concentration profile in biofilm was calculated. An experiment was carried out to measure velocity profile near a biofilm under oscillatory flow conditions and the influence of the turbulence on substrate uptake rate by the biofilm was also measured. Measured turbulence was in good agreement with the calculated one and the influence of the turbulence on the substrate uptake rate was well explained by the simulation.

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