冰层空气反循环连续取芯钻具：结构设计与冰芯卡断数值模拟

Structure Design and Ice Core Breaking Simulation of Continual Air-reverse-circulation Ice Coring Drill

摘要:

冰心包含大量的古气候资料和古生物学信息，这些信息对于从远古到现代的气候变化和生物进化都很重要。如何高效快速地获取无污染的冰心是极地科学家的一个重要课题。冰层空气反循环钻具采用双壁钻杆形成反循环通道，内管提供了从钻头底部到表面的冰屑和冰心的连续通道。钻具通过卡断机构卡断冰心，通过反循环通道不断运移冰心，从而实现连续钻具连续取心。本文采用ABAQUS软件对冰心卡断过程进行分析，运用XFEM断裂准则以及Explicit显式方法求解，选出适宜的卡断器尺寸和中心通道尺寸，从而得到更好的反循环钻进效果。

关键词:冰钻;结构设计;数值模拟;冰心卡断;反循环

Abstract:

Ice cores contain vast amounts of paleoclimate and paleontological information. These are important for climate change and biological evolution from ancient times to modern times. How to acquire clean ice cores efficiently and quickly is an important issue for polar scientists.The continual air-reverse-circulation ice coring drill use a double-wall drill pipe to form a reverse circulation channel. The inner pipe provides a continuous channel for transporting the ice chips and cores from the bottom of the hole to the ice sheet surface.The drill can break the ice core by its breaker, and move the ice core continuously through the reverse circulation channel, so as to realize the continual coring. By using ABAQUS software, this paper analyzes the process of ice core breaking, use of XFEM fracture criterion and Explicit method, choose appropriate breaker size and center channel size, so as to get better effect of reverse circulation drilling.

Key words:ice drilling; structure design; numerical simulation; ice core breaking; reverse circulation