使用南昌大学制备的气辅挤出成型设备,研究了气体压力和流量对熔体/气体两相流界面稳定性的影响,通过实验得出,实现气辅挤出的条件是口模内注气点处气体压力大于等于熔体的压力,而P_(melt)≈P_(gas)鲫是实现稳定气辅挤出的前提条件;实验还表明控制气体流量对实现稳定挤出非常重要,当气体流量为0.4 m~3/s时,熔体以稳定层流形式挤出,气体流量增大到2 m~3/s时,气体产生紊流并强迫挤出物以波纹状进行抖动挤出.
We used the gas-assisted extrusion(GAE)equipment made in Nanchang University to investigate the gas pressure and gas mass flow influenced on the two-phase flow stability in the melt/gas flow interface. These experiments have shown that the gas can be injected into the GAE die when the gas pressure is higher than the melt pressure at the gas injection point. When the gas pressure is equal to the flowing polymer's pressure, then a stable, uniform gas layer is formed at the interface between the molten polymer and the metal die. In addition these experiments also indicate that the control of gas mass flow appears to be an important part of obtaining a stable extrusion. When the gas flow is 0.4 m~3/s the melt extrude in the form of laminar, when the gas mass flow increases to 2 m~3/s a periodic product deformation termed 'blistering' is observed and the gas generated turbulence forces the melt vibration extrusion.
参考文献
| [1] | R. F. Liang;M. R. Mackley .The gas-assisted extrusion of molten polyethylene[J].Journal of Rheology,2001(1):211-226. |
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