A low-cost and reliable propellant flow controller is necessary to offer competitive electric propulsion systems. This paper first reviews xenon flow control methods for Hall thrusters and ion engines. Through a trade study, a simple and low-cost xenon flow controller applying a heated capillary is proposed. The test article is fabricated based on a developed theory and tested with xenon. The estimation based on laminar flow shows slightly different characteristics from those of the experiment, although the Reynolds number indicates a laminar condition. The turbulent flow assumption is in good agreement with the experiment at a high mass flow rate while the flow characteristics are between laminar and turbulent at a low mass flow rate. That implies that the surface roughness and tube curvature induce the laminar–turbulent transition even in the low mass flow rate case. To obtain a wider flow rate range, maintaining laminar flow in the capillary is desirable because of the high sensitivity of the friction coefficient with temperature in the laminar flow. Component improvements achievable through miniaturization and reduction of the inner wall surface roughness and capillary curvature are considered to be necessary to prevent the turbulent transition.

低成本，可靠的推进剂流量控制器是提供竞争性电力推进系统所必需的。本文首先回顾了霍尔推力器和离子发动机的氙气流量控制方法。通过行业研究，提出了一种使用加热毛细管的简单且低成本的氙流量控制器。该测试物品是根据发达的理论制造的，并使用氙气进行了测试。尽管雷诺数表示层流状态，但基于层流的估计显示出与实验特征略有不同。在高质量流量下，湍流假设与实验非常吻合，而在低质量流量下，流动特性在层流与湍流之间。这意味着即使在低质量流量情况下，表面粗糙度和管曲率也会引起层流湍流转变。为了获得更宽的流速范围，在毛细管中保持层流是理想的，因为层流中摩擦系数对温度具有很高的敏感性。为了防止湍流过渡，必须通过缩小和减小内壁表面粗糙度和毛细管曲率来实现组件改进。