Experimental Investigation of the Effect of the Bubble Cone on the Cooling Jets used in the Blown Film Manufacturing Process

Abstract

Abstract An experimental investigation was performed to characterize the flow field produced by a dual-lip air ring used in the blown-film manufacturing process for a solid model with a blow-up ratio of 3.5 similar to the shape of a typical LLDPE bubble. Distributions of the static and fluctuating pressure on the model and the flow field above the forming cone were measured for a range of settings on the dual-lip air ring. It was found that the distribution of the pressure on the bubble below the forming cone had many features similar to the measurements for a bubble with a blow-up ratio of 2.5 [1]. In the region above the forming cone, the upper jet appeared to merge with the lower jet rather than entraining the lower jet as was observed for a bubble with a blow-up ratio of 2.5 [1]. This resulted in a smaller local maximum in the normalized fluctuating pressure in the region above the forming cone and would likely result in less heat transfer in this region. It was also found that the initial angle of th...