三层共挤吹膜机头流道流场的数值模拟

多层共挤吹膜机头被广泛应用于复合薄膜加工领域,具有设备简单、成本低廉、产品质量优良等优点。以LDPE/HDPE/LDPE三层复合薄膜为例,将实际使用的一种三层共挤吹膜机头作为模具,利用软件Polyflow对熔体在机头流道内的等温流动过程进行求解,并分析了流道内的压力场、速度场、层与层之间的界面位置。研究结果表明,在层分配流道中熔体流动的方向,由沿螺旋槽的周向流动逐渐过渡为沿挤出方向的轴向流动;在各层分配流道汇入共挤出流道的位置处的速度场发生了改变,即出现了“次流动”;在口模出口端面位置处,熔体各层之间的界面发生了偏移,界面1和界面2均有向中间层熔体偏移的趋势。

液压破碎锤内锥阀中流道流场的数值分析

通过对液压破碎锤内锥阀内流道流场进行数值计算和模拟,探讨了不同情况下液压锥阀内流场包括流道速度场、压力场、流线和涡量线等的分布情况,分析了产生涡旋的位置和强度,找出了造成能耗的主要原因。结果表明,通过对锥阀阀座的优化设计,减少了流线的疏密程度和涡旋的大小,降低了能量损失,负压区也随之改变,减少了噪声,提高了能量利用率。

Study of measurements of air velocity transducer deriving average air velocity of roadway based on one-dimensional linear regression

One-dimensional linear regression equation between measured value of air velocity transducer and the average air velocity was established by experimental data. The effect is to be evaluated. Through judging the parameters, one-dimensional linear equation established is valid. Regression equation can approximately put the measurements of air velocity transducer into the value of average air velocity. The distribution of air velocity field is simulated using Comsol in the conditions of the same length of roadway, the same air velocity and different sections.