无纺织布喷熔射流拖网表面流场特性研究

本文的工作是对喷熔无纺织布的常用生产设备-喷熔机的风场特性及流动控制进行研究.通过理论分析、数值模拟和模型实验三个方面对问题展开了具体的研究,首先对喷熔机风场流动进行理论分析并建立数学模型,然后进行数值模拟,最后根据模型相似理论,制作比尺为3∶1的有机玻璃模型,使用90N10型热线风速测量系统(HFA),参考数值模拟工况对喷熔装置风场流动进行了实验测量,这三个部分工作彼此验证,补充和完善.数值模拟结果和实验测量结果基本一致,吸风装置工作状态对拖网板上方流场有重要影响.随着挡风板开度和主副吸风速度搭配的改变,拖网上方流场呈现规律性的变化.研究表明在恰当的挡风板开度和吸风速度下,拖网上方流场速度分布和压力分布的均匀性都有显著提高,进而使无纺布孔径更小更均匀,孔隙形状和孔隙结构更为规整,提高了无纺布的均匀性、强度以及过滤效率.

Study on the collecting web flow characteristics of melt-blown jet

Based on the theory analysis of turbulence, the numerical simulation and the experiment, the melt-blown (MB) flow characteristics and the flow control on collecting web were investigated in this paper. Firstly, numerical simulation was used to investigate the flow process in order to optimize the technical parameters. Then, experiment measurement was performed by using the Dantec Hot Wire Anemometry system (Dantec, Streamline 90N10) in the physical model. The numerical simulation results were consistent with the experimental results, the flow characteristics on collecting web were affected by the speed of suction equipment and its regulation plate opening angle. With the change of the plate opening angle and main/auxiliary suction speed, the distribution of flow speed and pressure on collecting web were different. Taking into account of these facts, the distribution of speed and pressure were improved evidently at the optimal main/auxiliary suction speed and the suitable opening angle, then the aperture of MB non-woven fabric was smaller and more uniform, its hole-shape and structure was more orderly. Furthermore the uniformity, intensity and filtration efficiency were enhanced for MB non-woven fabric.