In the air reverse circulation drilling system,there is a positioning device also called correcting block between the inner tube and the outer tube of the double wall. The current correcting rectangular block usually lead to greater loss on the circulatory system pressure,so the structure of correcting block is optimized with the help of computational fluid dynamics. Researches on block structure of double-wall drill annular gap are carried out,and the square,triangle,trapezoid, and hexagon correcting block are designed. Using pressure changes as the evaluation criteria, the numerical simulation on pressure field of correcting block is made with computational fluid dynamics software. Finally, the hexagonal correcting block is chosen. Then the three-dimensional numerical simulation on the pressure field of hexagonal block is made. It is further verified that hexagonal blocks can reduce the local pressure loss. Compared to the characters of other several correcting blocks,it owns a superior structure.%气体反循环钻具系统中双壁钻具内外管之间有同轴定位装置导正块.目前使用的长方形导正块对循环系统压力损耗较大,故借助计算流体动力学对导正块结构进行优化.针对双壁钻具环状间隙内导正块结构开展研究,设计出正方形、三角形、梯形和六边形导正块.以压力变化为评价标准,通过计算流体动力学软件对导正块处压力场进行数值模拟,最后优选出六边形导正块.再对六边形导正块处压力场进行三维数值模拟,进一步验证六边形导正块可使局部压力损失减小,相对于其他几种导正块性状而言,是较优结构.
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