| 摘要: |
| 针对航天器贮箱内液体推进剂的毛细输运过程，对单个毛细管内的液面爬升过程进行模拟，采用相场法追踪气液相界面，建立了毛细爬升的二维轴对称模型。将模拟结果与根据Jurin定律以及Lucas-Washburn模型计算得到的结果进行对比验证，并研究了不同重力及低温工质情况下的毛细爬升高度和速度。结果表明：在有效重力较小的情况下，毛细爬升过程可分为3个阶段；在有效重力较大的情况下，由于爬升过程中液体自身重力不可忽略，毛细爬升过程可分为4个阶段。有效重力越大，液体爬升高度和速度越小。初始阶段表面张力越大的低温流体，其爬升高度和速度越大；在后续爬升过程中，由于黏性力的作用，液氢的毛细爬升速度先后依次超过水、液氮和液氧的毛细爬升速度。 |
| 关键词: 毛细流动 重力效应 相场法 低温流体 爬升高度 |
| DOI： |
| Received:July 14, 2022Revised:September 06, 2022 |
| 基金项目:国家自然科学基金（51936006） |
|
| Numerical Simulation of Dynamic Capillary Rise with Cryogenic Fluids under Microgravity |
|
Yi Tianhao1,2, Qiu Yinan1, Xu Yuanyuan1, Wu Jingyi2, Lei Gang1, Yang Guang1,2
|
| (1.State Key Laboratory of Technologies in Space Cryogenic Propellants;2.School of Mechanical Engineering, Shanghai Jiao Tong University) |
| Abstract: |
| Spacecraft use surface tension to transport liquid fuel and continuously provide gas-free propellants to engines. To ensure the normal operation of spacecraft, it is important to study the capillary flow behavior of liquid propellants. In this study, the capillary rise process was simulated using a single capillary tube, and the gas-liquid interface was captured using the phase-field method. A two-dimensional axisymmetric model of capillary rise was built and solved using the finite element method. To validate the model, numerical results were compared with those calculated using Jurin’s law and the Lucas-Washburn model. The relative errors were 4.44% and 5.21%, respectively, which confirmed the feasibility of the model for simulating the dynamic capillary rise process. Based on the verified model, the height and velocity of the capillary flow were investigated using different gravitational accelerations and cryogenic fluids. The results showed that when the effective gravity was small, the capillary rise process could be divided into three stages: purely inertial, inertial-viscous, and purely viscous. When the effective gravity is high, the capillary rise process can be divided into four stages, because the gravity of the liquid in the tube cannot be ignored. The four stages are purely inertial, inertial-viscous, viscous-gravitational, and purely gravitational. In addition, the height and velocity of the capillary flow decreased as the effective gravity increased. In the initial stage, the higher the surface tension of the cryogenic fluid, the greater the rising height and velocity. As the liquid level increases, the viscous force gradually increases. The velocity of the capillary flow with liquid hydrogen exceeded that with water, liquid nitrogen, and liquid oxygen. |
| Key words: capillary flow gravity effect phase-field method cryogenic fluids rising height |
