Numerical Simulation And Experiment Study On Air Flow Field Of The Melt-Blowing Swirl Nozzle

Melt-blowing technology has been widely applied in the manufacturing of micro-nano fiber nonwovens. The slot die and annular die are the most common used melt-blowing dies. The swirl nozzle with special structure is used and researched in this study and its flow field including both velocity field and temperature field are simulated and measured, which can help learn the drawing mechanism of melt blowing fibers, and then direct the optimal design and further improve the quality of melt blowing production.Firstly, Fluent 6.3 is adopted to simulate the 3D flow field of swirl nozzle to get its melt-blowing velocity field, temperature field, path line and other fluid motion informations, the simulation parameters are based on experiment. Then change the airflow pressure and temperature to simulate the flow field of swirl nozzle again. The simulation results prove that the flow field of swirl nozzle is rotational and airflow velocity and temperature get its maximum in the area near the swirl nozzle, and then both velocity field and temperature field decay quickly into the around air environment. The velocity field is mostly affected by inlet pressure and temperature field is mostly affected by inlet temperature.Secondly, the flow field of swirl nozzle of which both velocity field and temperature field are measured by Hot Ware Anemometer to verify numerical simulation, and then the numerical simulation of 3D flow field of swirl nozzle is proven to be practical by comparing results of experiments and numerical simulation. Furthermore, the comparison also shows that the velocity and temperature of air jets are high in the exit of nozzle and then decay fast until reaching far flow field. The velocity decay is faster than temperature.Finally, melt blowing spinning is carried out by using swirl nozzle in different airflow pressure and temperature conditions. The influence on fiber properties which is caused by the change of flow velocity and temperature is discussed and get the following results. The higher the airflow pressure and temperature, the finer the fiber obtained. The comparison between swirl nozzle and dual slot nozzle is studied simultaneously and the results prove that the fiber spun from swirl nozzle is not better than the fiber spun from dual slot nozzle in both fiber diameter and fiber unevenness.