دانلود رایگان مقاله مطالعات تجربی در مورد اثر فاصله بر رفتار چکیدن اسلب پلی متیل متاکریلات

Abstract

Experiments were carried out to study the dripping behavior of vertical burning thermally thin polymethyl-methacrylate (PMMA) with different spacings parallel to the wall. With spacings of 7, 10, 13, 16, 19, 22, and 25 mm, the dripping behavior was studied by infrared video image analysis, and the mass retention was recorded by the load cells. As the spacing increased, the dripping time, dripping mass, and burnout growth distance first increased and then decreased. The minimum value was observed at the 13 mm case. The dripping behavior is assumed to correspond to the net heat flux to the surface, extensional viscosity, and gravitational force of melting PMMA. In this study, the dripping behavior was investigated using uniform PMMA samples with 200 mm height, 50 mm width, and 2 mm thickness.

4. Conclusion

The experimental results obtained in this study provide a hypothesis for the dripping behavior of vertical burning PMMA materials with different spacings to the wall using pure PMMA samples with 200 mm height, 50 mm width, and 2 mm thickness. Different dripping behaviors were observed depending on the spacings of 7, 10, 13, 16, 19, 22, and 25 mm, and the spacing effects were analyzed. The dripping process was observed using an infrared camera. As the spacing increased, the dripping time and mass and burnout growth distance first decreased and then increased. The predicted critical value occurred at a spacing of 13 mm. No effect was observed when the spacing exceeded 25 mm. The large-size dripping behavior was assumed to correspond to the net heat flux to the surface, extensional viscosity, and gravitational force of melting PMMA. This work was intended for an in-depth analysis and a better understanding of the mechanism of the effects of spacing between wall and thin PMMA material on the dripping behavior under vertical burning conditions. Further studies are necessary to study the effects of dripping behavior on the upward flame spread over thin PMMA.