Abstract:

The visual pressure chamber was designed. The pressure inside chamber can be measured and controlled. The camera can record the process of defoaming through the glass. To quantitatively study the relationship between defoaming rate and pressure， it is necessary to ensure that the morphology and size of the bubbles studied are basically the same. This article explores a bonding method of PET film that can control the diameter deviation of the bubbles within ±10 % for easy experimental comparison， while also eliminating bubbles through conventional processes without irreversible effects. The experiment found that below the critical pressure， the pores hardly undergo deformation. Above the critical pressure， the rate of pore contraction exhibits a positive correlation with the pressure. Through theoretical analysis， one mathematical model has been abstracted to represent the compression behavior of pores under pressure. In Abaqus， the simulation of the defoaming process was conducted using an explicit dynamic fluid cavity model. The simulated results obtained using the fluid cavity model in Abaqus are generally consistent with the experimental observations. When the film and bubbles are subjected to pressure， the film overcomes its own strength and undergoes a brief elastic deformation， and then begins a nonlinear change. At the same time， the internal space of the bubbles begins to shrink. When PET film is subjected to pressure， the deformation starts from the middle and gradually diffuses towards both sides. The internal air pressure of the bubbles increases until a state of mechanical equilibrium is reached.

Key words: visual pressure chamber, defoaming, polyethylene terephthalate, film, Abaqus, fluid cavity, explicit dynamic