Vaporizing liquid microthruster is a relatively new concept for evaporation based propulsive system. The research interest in vaporizing liquid microthruster mainly comes from its simplicity and the use of green propellant: water. This paper presents the study of a highly compact additively manufactured vaporizing liquid microthruster of 38 × 22 × 8 mm in dimension. The heat transfer enhancement effect of micro pin fins for vaporizing process has been investigated using modeling and computational fluid dynamics simulation, followed by experiments to validate the results. It has been shown that all micro pin fins (square, diamond, circular) with different array arrangements (staggered and inline) can enhance heat transfer. Square shaped pin fin exhibited the best heat enhancement performance with an increase in dimensionless total thermal resistance of 14.65% (as compared to blank vaporizing liquid microthruster) due to its large contacting area, while the circular shape was least effective. Meanwhile, the inline arrangement was found to induce a significant fluctuation in transverse flow velocity between the columns, which promotes heat convection. The vaporizing liquid microthruster prototype was produced using a specialty resin of good heat resistance up to 350 °C as confirmed by the thermogravimetric analysis. Thrust performance of the prototype was measured using a torsional thrust stand in a vacuum chamber. The vaporizing liquid microthruster with square micro pin fins and in inline configuration has produced the highest thrust of 740.2 μN at 2 μl/s flow rate, giving a specific impulse of 37.7s. The developed prototype could be implemented as micropropulsion system for nanosatellites, such as CubeSat and PocketQube.

汽化液体微推进器是基于汽化的推进系统的一个相对较新的概念。汽化液体微型推进器的研究兴趣主要来自其简单性和使用绿色推进剂：水。本文介绍了对尺寸为 38 × 22 × 8 mm 的高度紧凑的增材制造汽化液体微型推进器的研究。使用建模和计算流体动力学模拟研究了微针翅片在汽化过程中的传热增强效果，并通过实验验证了结果。已经表明，所有具有不同阵列排列（交错和直列）的微型针翅片（方形、菱形、圆形）都可以增强热传递。方形针翅因接触面积大而表现出最佳的热增强性能，无量纲总热阻增加了14.65%（与空白汽化液体微型推进器相比），而圆形的效果最差。同时，发现直列排列会引起柱间横向流速的显着波动，从而促进热对流。热重分析证实，汽化液体微型推进器原型是使用耐热性高达 350 °C 的特种树脂制成的。原型的推力性能是使用真空室中的扭转推力架测量的。带有方形微型针翅和直列配置的汽化液体微型推力器在 2 μl/s 流速下产生了 740.2 μN 的最高推力，给出 37.7 秒的比冲。开发的原型可以实现为纳米卫星的微型推进系统，例如 CubeSat 和 PocketQube。