scholarly journals Simulation of 3D vortex jets in plasma torch application

2021 ◽  
Vol 2145 (1) ◽  
pp. 012021
Author(s):  
W Kongpiboolkid ◽  
R Mongkolnavin

Abstract The gas tunnel type plasma jet is an effective heat source for thermal processing applications such as plasma spraying. The key concept of gas tunnel plasma is its torch configuration, especially the role of the vortex gas flow. This is very important for the stability and energy density of the plasma jet produced. This work studied the flow of gas vortex in 3 dimensions using a finite element simulation. The simulation is based on solving partial differential equations where the incompressible Navier-Stokes equation is used as a governing equation that describes the laminar flow. The geometry of the plasma torch investigated is based on the design by A. Kobayashi. Key parameters investigated were gas pressure, velocity and profile of the vortex. It can be shown that the simulation produced results that are better matched to the experimental result than the calculation done in previous work. The simulation can also show detailed pictures of the vortex and its properties within the plasma chamber. This study could be useful in the design optimization of the plasma torch in the future.

2013 ◽  
Vol 729 ◽  
pp. 364-376 ◽  
Author(s):  
John C. Bowman

AbstractIn addition to conserving energy and enstrophy, the nonlinear terms of the two-dimensional incompressible Navier–Stokes equation are well known to conserve the global integral of any continuously differentiable function of the scalar vorticity field. However, the phenomenological role of these additional inviscid invariants, including the issue as to whether they cascade to large or small scales, is an open question. In this work, well-resolved implicitly dealiased pseudospectral simulations suggest that the fourth power of the vorticity cascades to small scales.


2013 ◽  
Vol 791-793 ◽  
pp. 1493-1496
Author(s):  
Shou Chao Gu ◽  
Dong Xu Liu ◽  
Yu Fu Wang

Numerical simulation was conducted to investigate the external flow around airships with different tail layout, with the help of FLUENT 14.5, based on the incompressible Navier-Stokes equation and SST turbulent model. The aerodynamic information of the airships with different tail layout, such as pressure coefficient, torque coefficient and pressure distribution, were analyzed, and the numerical results showed the details of the airship surface flow and changes with different attack angle. According to the results, different tail layout had important influences on the aerodynamics and stability of airship. This will help to understand the aerodynamic characters around the tails of the stratospheric airship, and provide a reference in choosing tail layouts and the stability design of airships.


Author(s):  
Samuel I. En Lin

Enzyme-linked immunosorbent assays (ELISA), one of the most common immunoassays, is widely used for detection and quantification of chemical and biological molecules and is becoming more and more important in clinical diagnostics, food safety testing, and environmental monitoring. A major challenge in developing the CD-ELISA is to split the flow (e.g., bio-reagents) evenly on the micro-channels. The Coriolis force resultant from CD rotation can disturb the flow in the splitter region and thus cause the failure mode in delivering the solution from each reservoir in a pre-specified manner. In this study, we investigate on the effects of inlet pressure and Coriolis force on the splitting ratio under two splitter structures. The analysis is based on the incompressible Navier-Stokes equation and the simulation results agree well with our experimental work.


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