The concept of transmission conductance is required to describe phenomena occurring in a tube with wall pumping. This is because the gas flow is not constant along the length of the tube but decreases, which implies that the geometric conductance determined by dimensional parameters of the tube cannot be further used. In one of the previous studies, the transmission conductance of a cylindrical tube was analytically derived using the particle balance equation based on the continuity principle. However, the calculated results well agreed with those of the test particle Monte Carlo (TPMC) simulation only when the sticking coefficient was less than 0.1. This is due to the intrinsic limitation of the analytical method, in which the constant conductance of a tube of unit length with uniform wall pumping was used. In this study, we introduced another analytical method based on the cosine law and finite element analysis using the conductance of the tube of unit length as a function of the position in the tube, considering the beaming effect. Using both methods, the relative difference in transmission conductance with TPMC considerably decreased compared to the previous study when the sticking coefficient was greater than 0.1. The results can be used in the design of a non-evaporable getter coated tube or a cryogenic water pump using an adsorbing wall to determine characteristic dimensions. Furthermore, this can be employed in a windowless vacuum coupling or a distributed pumping system for various light source systems.

中文翻译：

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带壁泵的圆柱管的传输电导

需要传输电导的概念来描述管壁泵浦中发生的现象。这是因为气流沿管的长度不是恒定的而是减小的，这意味着不能进一步使用由管的尺寸参数确定的几何电导。在先前的一项研究中，圆柱形管的传输电导是使用基于连续性原理的粒子平衡方程分析得出的。然而，仅当粘附系数小于0.1时，计算结果与测试粒子蒙特卡罗（TPMC）模拟的结果非常吻合。这是由于分析方法的固有局限性，其中使用了具有均匀壁泵的单位长度管的恒定电导。在这项研究中，我们介绍了另一种基于余弦定律和有限元分析的分析方法，使用单位长度管的电导作为管中位置的函数，并考虑了束流效应。使用这两种方法，当粘附系数大于 0.1 时，与之前的研究相比，TPMC 的传输电导的相对差异大大降低。该结果可用于设计非蒸发性吸气剂涂层管或使用吸附壁确定特征尺寸的低温水泵。此外，这可以用于无窗真空耦合或用于各种光源系统的分布式泵浦系统。