An investigation of some parameter effects on the internal flow characteristics in the main nozzle

Abstract

The air-jet loom is widely used in the textile industry and the main nozzle is one of its key components. In this paper, the influence of some parameters, including the input air pressure and the structure of nozzle core and its internal diameter, on the internal flow field of the main nozzle is analyzed. Then the optimized structure of the main nozzle is proposed from the perspective of fluid dynamics. In the present simulations, the realizable [Formula: see text] model is applied to model the internal flow field of the main nozzle. The results show that the velocity in the annular throat reaches supersonic. Moreover, the pressure at the end of the nozzle core is the lowest in the main nozzle. It is also shown that the input air pressure has little effect on the axis velocity in Zone B, but on the other hand, has a great influence on the near-wall velocity field and the axis velocity in Zone C. In addition, an optimized structure of the nozzle core is proposed in this paper. It is found that with the proposed structure, the velocity boundary layer near the wall of Zone B in the accelerating tube can be well improved, and rapid diffusion of airflow in this area can be avoided. These help increase the moving speed of the weft yarn. Last but not least, we also show that decreasing of the internal diameter of the nozzle core improves the axis velocity of the weft accelerating tube. However, it brings a stronger turbulence at the same time.

Optimization of fluid characteristics in the main nozzle of an air-jet loom

“…The comparison in Figure 5 focuses on the exit jet flow velocity. When comparing the simulation result to the experiment result recorded in the paper of Jin et al., 18 we can see that our results are in good agreement in terms of tendency. The comparison in Figure 6 focuses on the centerline x -velocity of the nozzle.…”

“…Jin et al. 18 used the realizable k-ε model to simulate the fluid flow within a regular main nozzle and a proposed new main nozzle. In their design, they made a 45-degree cutoff on the nozzle core tip.…”

Towards simulation of force and velocity fluctuations due to turbulence in the relay nozzle jet of an air jet loom

“…The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article. Textile Research Journal 91 (9)(10) this article: This work was supported by the Ghent University Special Research Fund (BOF) (Grant No. 01D26216).…”

“…They performed simulations of the air flow inside several main nozzle geometries in order to obtain some basic design guidelines. Other examples of CFD investigations of the main nozzle are the works of Kim, Lim, Lee et al 8 , Belforte, Mattiazio, Viktorov et al 9 , Jin, Cui, Zhu et al 10 and He, Qian, Xue et al 11 . Not only the main nozzle but also the relay nozzles have been the subject of CFD investigations, albeit to a lesser extent.…”

“…Among the first to apply CFD to air jet looms were Oh et al 7 They performed simulations of the air flow inside several main nozzle geometries in order to obtain some basic design guidelines. Other examples of CFD investigations of the main nozzle are the works of Kim et al, 8 Belforte et al, 9 Jin et al 10 and He et al 11 Not only the main nozzle but also the relay nozzles have been the subject of CFD investigations, albeit to a lesser extent. By means of CFD, Kim et al 12 studied the flow field in the reed channel for several relay nozzle diameters, supply pressures and orientations.…”