ͺqA¬`Ι¨―ιCA`¬V~ [V(1)\ΟΏjΆ¬nΜ¨AV~ [VΖΐ±\
Numerical Simulation for Polymeric Foaming (1)|Numerical Simulations and Experiments on Homogeneous Nucleation|
ξXNYEtR OEcυqEε³TEJ_Ήh
Inamori, Kohjiroh / Hayama, Kaoru / Takada, Mitsuko / Ohshima, Masahiro / Tanigaki, Masataka
The effect of processing variables, such as concentration of dissolved gas, release rate of pressure and operating temperature, on bubble growth dynamics, nucleation rate and final bubble size was examined. In the polyethylene foaming process, fundamental experiments showed that bubble size increased when the release rate of pressure decreased, whereas bubble size decreased when the operating temperature decreased. Furthermore, a higher concentration of dissolved gas resulted in smaller bubble size. These results were confirmed by numerical simulations using Shafi's nucleation and bubble growth models. Both simulation and experimental results elucidated that release rate of pressure, concentration of dissolved gas and operating temperature are the principal factors which control bubble size and foam density in the physical foaming process.
Key words: Physical foaming / Homogeneous nucleation / Polymeric foam / Polyethylene