Comparison between Two Turbulence Models and Analysis of the Effect of the Substrate Movement on the Flow Field of a Plasma Jet

Abstract

In the first part of the present study, an appropriate inflow turbulent boundary condition is chosen. Then, a comparison is made between two turbulence models for a plasma jet discharged into air atmosphere. The plasma jet gas phase flow is predicted with the standard k−ε model and the RNG model of turbulence. Particles behavior is modeled using stochastic particles trajectories. A validation of the plasma jet model is made by comparison with experimental data.This part of the study shows that the flow features are better predicted with the RNG model. The choice of appropriate boundary conditions seems to be crucial for a better simulation of plasma thermal spraying. Afterwards, computations are performed for projection of Ni particles. It is found that the computed particles velocities and temperatures are also better predicted with the RNG model compared with the k−ε model. The second part of this study is concerned with the effect of the substrate movement on the gas flow field. This is performed in order to simulate a realistic coatings process where a relative movement between the torch and the substrate always exists. Three substrate velocities have been used and it is found that the flow fields are affected only very near the substrate wall.

Numerical Analysis of Fluid Flow and Heat Transfer by Means of a Unified Model in a Direct Current Electric Arc Furnace

“…However, the RNG model has a satisfactory precision and robustness in both the low Reynolds number region and high Reynolds number region, and it can even predict some laminar behavior. [ 37–39 ] Its calculated plasma arc velocity distribution agrees well with the measured velocity.…”

Research on Cooling Method in Surfacing Repair Process of Aero Compressor Blade

“…As the nozzle diameter increases, more fluid will participate in the heat exchange, resulting in an increase in the average convective heat flux across the wall. e theoretical results of the average convective heat flux calculated by the comparison formulas (22) to (26) have the same overall trend. When the nozzle diameter is 2 mm, the difference between the two curves is the smallest.…”

“…e simplified model of the impact "blade-fixture" is shown in Figure 16, which is to analyze the cooling effect of different impact parameters and obtain the best impact parameters. Many scholars have studied the choice of the turbulence model [20][21][22]. In turbulent impinging flow field, high wall velocity and fluid fluctuation can cause fully developed turbulence and the k-ε model is suitable for calculation [23].…”

The 2-D plasma thermal jet simulations with substrate interaction

“…(6) and Eq. (8). The SST-k-ω and RNG k-ε turbulence models has been adopted to obtain simulations results.…”

“…They studied using the CFD code FLUENT, the typical process of an Ar-He plasma jet, by analyzing the influence of the current, the flow of Ar, as well as the flow of He on the temperature field and that of speed. Abdellah El-hadj et al [8] compared the two turbulence models k-ε standard and RNG-K-ε in a plasma spray discharging into the ambient air. It has been considered that the presence of the injected particles does not significantly affect the plasma.…”