中文摘要：

采用变截面导流筒真实三维实体模型,通过数值模拟的方法,以流体流动均匀性和压降作为综合衡量依据,研究了变截面导流筒装置中关键结构参数的变化对其内部流体流动均匀性和流体流动阻力的影响规律,得出了导流筒的结构参数L,H,θ与壳程进口处流体流动状况的对应关系,证实了在适当范围内调整上述结构参数,不仅可以提高壳程进口处流体流动均匀性,而且可以有效降低壳程流体的压力损失。从导流筒换热器的流体流动均匀性和壳程压降角度出发,推荐L,θ,H的取值范围分别是：L=50～70mm,θ=7°～12.5°,H=50～100mm。研究结果为变截面导流筒换热器优化设计提供了参考依据。

英文摘要：

Taking the fluid flow uniformity and pressure drop as the evaluation indexes,the real 3D solid numerical model is adopted to investigate the influence of geometrical structure parameters of the tapered flow distributor on flow uniformity and flow resistance.The corresponding relation charts of flow status in entrance region of shell side and key structure parameters L,θ,and H are obtained,where L is the distance between the inner surface of jacket and the exine of internal liner barrel,θ is the inclination angle of inlet section where fluid enter the draft-tube,and H is the distance from the high end of the internal liner barrel to the tube plate.By adjusting the above structure parameters in proper ranges,the flow uniformity at the entrance section of the shell side can be improved and the pressure drop in the shell side is decreased effectively.The ranges of L,θ,and H values recommended are：L=50—70 mm,θ=7°—12.5°,H=50—100 mm for the optimum design.