エレクトロフユージョン継手の熱融着シミュレーション
A Numerical Simulation of Welding Process with Electrofusion Joint
船津和守・梶原稔尚・中野祥生・長嶋勇希・西村寛之
Funatsu, Kazumori / Kajiwara, Toshihisa / Nakano, Yoshio / Nagashima, Yuuki / Nishimura Hiroyuki
We have developed the prediction method of welding process between the electrofusion joint and the gas pipes using the finite difference method. We performed the simulation of welding process for the pipes of diameters 50 mm, 150 mm and 200 mm, and obtained the results as follows : 1) The predicted values of the temperature in the fusion interface and the thickness of melting layer in the pipe were in agreement with the experimental values for the pipe of diameter 50 mm, and the reliability of the numerical method was confirmed. 2) It was found that the clearance between a joint and a pipe prevented the development of melting layer in the pipe and cause the increase of the maximum temperature which had the hazard of thermal degradation of polymer. This tendency became more remarkable for the pipes of larger diameter. 3) In regard to the arrangement of wire, the wire pitch and the depth of wire from joint interface were desirable to be as small as possible except for the break of joint. 4) In order to develop the enough melting layer of pipe and prevent the increase of maximum temperature, it was desirable that the heat flux was smaller and the heating time was longer.
Key words: Electrofusion / Welding process / Numerical simulation / Finite difference method / Gas pipe