The Numerical Simulation of Aerodynamics of the Frontal Aerodynamic Screen of ExoMars Project Descent Vehicle and the Analysis of Flow Pattern in the Base Area and Near Wake

2020 ◽  
Vol 54 (7) ◽  
pp. 712-718
Author(s):  
A. V. Babakov ◽  
V. S. Finchenko
Keyword(s):  
Numerical Simulation ◽  
Flow Pattern ◽  
Near Wake ◽  
Base Area ◽  
Descent Vehicle

Aerodynamic Behavior of Asymmetric Jets in 3-D Furnaces

1994 ◽  
Author(s):  
F. M. El-Mahallawy ◽  
M. A. Hassan ◽  
M. A. Ismail ◽  
H. Zafan
Keyword(s):  
Numerical Simulation ◽  
Flow Pattern ◽  
Numerical Experiments ◽  
Recirculation Zone ◽  
Reverse Flow ◽  
Three Dimensional ◽  
Flow Region ◽  
Stabilization Method ◽  
Flow Features

The purpose of this paper is to present and evaluate numerical experiments illustrating the flow features in a 3-D furnace utilizing unconventional asymmetrical jet that creates natural recirculation zone. The numerical simulation of this aerodynamic stabilization method have unveiled the three-dimensional nature of the flow pattern which possesses a quite large reverse flow region. The size and strength of the built recirculation zone would be capable of stabilizing the burning of low-quality fuels.

scholarly journals Direct Observation of Filling Process and Porosity Prediction in High Pressure Die Casting

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1099 ◽  
Author(s):  
Hanxue Cao ◽  
Chao Shen ◽  
Chengcheng Wang ◽  
Hui Xu ◽  
Juanjuan Zhu
Keyword(s):  
Numerical Simulation ◽  
High Pressure ◽  
Flow Visualization ◽  
Flow Pattern ◽  
Experimental Verification ◽  
Die Casting ◽  
Filling Process ◽  
High Pressure Die Casting ◽  
Visualization Experiment ◽  
Pressure Die Casting

Although numerical simulation accuracy makes progress rapidly, it is in an insufficient phase because of complicated phenomena of the filling process and difficulty of experimental verification in high pressure die casting (HPDC), especially in thin-wall complex die-castings. Therefore, in this paper, a flow visualization experiment is conducted, and the porosity at different locations is predicted under three different fast shot velocities. The differences in flow pattern between the actual filling process and the numerical simulation are compared. It shows that the flow visualization experiment can directly observe the actual and real-time filling process and could be an effective experimental verification method for the accuracy of the flow simulation model in HPDC. Moreover, significant differences start to appear in the flow pattern between the actual experiment and the Anycasting solution after the fragment or atomization formation. Finally, the fast shot velocity would determine the position at which the back flow meets the incoming flow. The junction of two streams of fluid would create more porosity than the other location. There is a transition in flow patterns due to drag crisis under high fast shot velocity around two staggered cylinders, which resulted in the porosity relationship also changing from R1 < R3 < R2 (0.88 m/s) to R1 < R2 < R3 (1.59 and 2.34 m/s).

Effect of Slag Layer on Flow Patterns in a Gas Stirred Ladle

2006 ◽  
Vol 510-511 ◽  
pp. 490-493 ◽  
Author(s):  
Sung-Ho Cho ◽  
Sung Hwan Hong ◽  
Jeong Whan Han ◽  
Byung Don You
Keyword(s):  
Numerical Simulation ◽  
Flow Pattern ◽  
Model Experiment ◽  
Central Area ◽  
Side Wall ◽  
Slag Layer ◽  
Flow Patterns ◽  
Water Model ◽  
Slag Viscosity ◽  
Mixing Behavior

Flow patterns and mixing behaviors in a gas stirred steelmaking ladle with a slag layer were discussed using a water model experiment as well as a numerical simulation. While the water model experiment was performed to investigate the effect of slag on the mixing behavior in ladle, the numerical simulation was carried out to figure out the flow pattern in ladle with a slag layer. Slag viscosity and its thickness in ladle were considered as major variables. It was found that a slag layer made a great change in the flow pattern in ladle, which, in turn, affected on the mixing behavior in ladle. A flow pattern without a slag layer showed that rising bubbles eventually made a recirculation loop at the central area of the ladle and this flow pattern was regarded as a favorable flow pattern for the better mixing behavior. However, a flow pattern with a slag layer showed distorted and localized recirculating loop near side wall below slag layer. This eventually gave a longer mixing time in ladle with a slag layer. Moreover, as the gas flow rate increases, slag existing on top of the ladle was found to be entrained into the melt. Slag viscosity and its thickness were found to be major variables affecting the behavior of slag entrainment. Lower the slag viscosity and thicker the slag layer, much more slag on top of the melt was entrained into the melt.

Understanding the occurrence of the surface turbulence in a nonpressurized bottom gating system: Numerical simulation of the melt flow pattern

2015 ◽  
Vol 232 (3) ◽  
pp. 230-241 ◽  
Author(s):  
Ali Kheirabi ◽  
Amir Baghani ◽  
Ahmad Bahmani ◽  
Morteza Tamizifar ◽  
Parviz Davami ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Liquid Metal ◽  
Flow Pattern ◽  
Oxide Films ◽  
Critical Value ◽  
Surface Velocity ◽  
Complete Agreement ◽  
Gating System ◽  
Melt Flow ◽  
Surface Turbulence

Surface turbulence during the filling of the mold triggers the entrainment of oxide films, which appears to be detrimental to the soundness of the final casting. Nonpressurized and bottom-gating systems have been employed in order to avoid such casting defects by reducing the surface velocity of the liquid metal. However, recent studies have shown that the melt front velocity in the mold entrance may exceed the critical value in the nonpressurized and bottom-gating systems. Therefore, a study was conducted on numerical simulation melt flow pattern in nonpressurized and bottom-gating systems. It was noted that the liquid metal enters the gate and then mold cavity with a higher velocity by formation of dead zones and vortex flows in runner's end. Therefore, the current designs based on conventional gating system ratio seem to be not optimized and unable to avoid the surface turbulence. Numerical results were in complete agreement with experimental observations. Understanding the reasons for occurrence of the surface turbulence in nonpressurized and bottom-gating systems provides information on the required steps to improve the design of the gating systems and minimize the entrainment of oxide films during the filling of the mold.

scholarly journals Effects of Hydrostatic Pocket Shape on the Flow Pattern and Pressure Distribution

1995 ◽  
Vol 1 (3-4) ◽  
pp. 225-235 ◽  
Author(s):  
M. J. Braun ◽  
M. Dzodzo
Keyword(s):  
Numerical Simulation ◽  
Pressure Distribution ◽  
Flow Pattern ◽  
Stokes Equations ◽  
The Other ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Hydrostatic Bearing ◽  
Collocated Grid ◽  
Dimensionless Formulation

The flow in a hydrostatic pocket is numerically simulated using a dimensionless formulation of the 2-D Navier-Stokes equations written in primitive variables, for a body fitted coordinates system, and applied through a collocated grid. In essence, we continue the work of Braun et al. 1993a, 1993b] and extend it to the study of the effects of the pocket geometric format on the flow pattern and pressure distribution. The model includes the coupling between the pocket flow and a finite length feedline flow, on one hand, and the pocket and its adjacent lands on the other hand. In this context we shall present, on a comparative basis, the flow and the pressure patterns at the runner surface for square, ramped-Rayleigh step, and arc of circle pockets. Geometrically all pockets have the same footprint, same lands length, and same capillary feedline. The numerical simulation uses the Reynolds number based on the lid(runner) velocity and the inlet jet strengthFas the dynamic similarity parameters. The study aims at establishing criteria for the optimization of the pocket geometry in the larger context of the performance of a hydrostatic bearing.

scholarly journals Modeling Emission Flow Pattern of a Single Cruising Vehicle on Urban Streets with CFD Simulation and Wind Tunnel Validation

2020 ◽  
Vol 17 (12) ◽  
pp. 4557 ◽  
Author(s):  
Xueqing Shi ◽  
Daniel (Jian) Sun ◽  
Ying Zhang ◽  
Jing Xiong ◽  
Zhonghua Zhao
Keyword(s):  
Numerical Simulation ◽  
Wind Tunnel ◽  
Flow Pattern ◽  
Cfd Simulation ◽  
Wind Tunnel Experiment ◽  
Atmospheric Pollutants ◽  
Future Application ◽  
Dispersion Pattern ◽  
Strong Positive Correlation ◽  
Cfd Numerical Simulation

Transportation has become one of the primary sources of urban atmospheric pollutants and it causes severe diseases among city residents. This study focuses on assessing the pollutant dispersion pattern using computational fluid dynamics (CFD) numerical simulation, with the effect and results validated by the results from wind tunnel experiments. First, the wind tunnel experiment was carefully designed to preliminarily assess the flow pattern of vehicle emissions. Next, the spatiotemporal distribution of pollutant concentrations around the motor vehicle was modeled using a CFD numerical simulation. The pollutant concentration contours indicated that the diffusion process of carbon monoxide mainly occurred in the range of 0−2 m above the ground. Meanwhile, to verify the correctness of the CFD simulation, pressure distributions of seven selected points that were perpendicular along the midline of the vehicle surface were obtained from both the wind tunnel experiment and the CFD numerical simulation. The Pearson correlation coefficient between the numerical simulation and the wind tunnel measurement was 0.98, indicating a strong positive correlation. Therefore, the distribution trend of all pressure coefficients in the numerical simulation was considered to be consistent with those from the measurements. The findings of this study could shed light on the concentration distribution of platoon-based vehicles and the future application of CFD simulations to estimate the concentration of pollutants along urban street canyons.

Numerical Simulation of Gas Flow Pattern in Cyclone Spray Scrubber

2011 ◽  
Vol 233-235 ◽  
pp. 701-706
Author(s):  
Bing Tao Zhao ◽  
Yi Xin Zhang ◽  
Kai Bin Xiong
Keyword(s):  
Numerical Simulation ◽  
Fluid Flow ◽  
Flow Pattern ◽  
Gas Flow ◽  
Stokes Equations ◽  
Tangential Velocity ◽  
Navier Stokes ◽  
Computational Domain ◽  
Spray Scrubber ◽  
Cfd Method

The numerical simulation of the fluid flow is presented by CFD technique to characterize the flow pattern of cyclone spray scrubber. In this process, the Reynolds-averaged Navier-Stokes equations with the Reynolds stress turbulence model (RSM) for fluid flow are solved by use of the finite volume method based on the SIMPLE pressure correction algorithm in the fluid computational domain. According to the computational results, the tangential velocity, axial velocity and turbulence intensity of the gas flow are addressed in the different flowrate. The results indicate that the CFD method can effectively reveal the mechanism of gas flow in the cyclone spray scrubber.

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