水驱动弹头辅助注塑弹头的穿透行为

Projectile Penetration Behavior ofWater-Projectile-Assisted Injection Molding

残余壁厚(RWT)是表征水驱动弹头辅助注塑成型(WPAIM)管件质量的一个重要指标,直接受弹头的穿透行为影响。为了研究WPAIM过程中弹头的穿透行为及相应的RWT分布规律,文中基于计算流体动力学(CFD)方法对WPAIM过程进行了数值模拟,模拟结果与实验结果吻合较好。研究结果表明,WPAIM管在直线段的RWT相对均匀,而在曲线段,外凸侧RWT大于内凹侧RWT,两者之间的RWT差值小于水辅助注射成型(WAIM)管。通过对WPAIM中弹头穿透行为与WAIM中水的穿透行为分析发现:穿透前沿附近的压力分布WPAIM较WAIM更均匀,穿透两侧的速度差也更小,弹头能更好地沿型腔中心穿透,提高管件壁厚的均匀性;无论是在直段或是弯曲段,两者的穿透过程都是在不断加速的,WAIM穿透速度更快,而WPAIM的加速过程较稳定。

Residual wall thickness(RWT)is an important indicator that characterizes the quality of water-projectile-assisted injection molding(WPAIM)pipe fittings,which is directly affected by the penetration behavior of warhead.In order to study the penetration behavior of projectile and corresponding RWT distribution law in WPAIM process,the WPAIM process was numerically simulated based on computational fluid dynamics(CFD)method,and the simulation results are in good agreement with the experimental results.The research results indicate that the RWT of WPAIM pipes is relatively uniform in the straight section,while in the curved section,the RWT on the convex side is greater than that on the concave side,and the difference in RWT between the two is smaller than that of water assisted injection molding(WAIM)pipes.By comparing and analyzing the penetration behavior of warheads in WPAIM with that of water in WAIM,it is found that the pressure distribution near the penetration front is more uniform in WPAIM compared to WAIM,and the velocity difference between the penetration sides is also smaller.The projectile can better penetrate along the center of cavity,improving the uniformity of pipe wall thickness;the penetration process of both is continuously accelerating,whether in the straight or curved section.WAIM penetration speed is faster,while the WPAIM acceleration process is more stable.