Dynamics of buoyancy-driven microflow in a narrow annular space

作     者：Yanzhong WANG Yaping ZHANG Kai YANG Boji LU Hao GAO Yanzhong WANG;Yaping ZHANG;Kai YANG;Boji LU;Hao GAO

作者机构：School of Mechanical Engineering&AutomationBeihang UniversityBeijing 100191China Bejing SpacecraftBeijing 100094China School of Mechanical and Electrical EngineeringSanming UniversitySanming 365001China 

出 版 物：《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 (浙江大学学报（英文版）A辑（应用物理与工程）)

年 卷 期：2023年第24卷第12期

页      面：1131-1139页

核心收录：

学科分类：08[工学] 080103[工学-流体力学] 0701[理学-数学] 0801[工学-力学（可授工学、理学学位）] 

基　　金：supported by the National Natural Science Foundation of China(No.U1937603). 

主　　题：Liquid floated gyroscope(LFG) Annular channel Roughness feature Fluid drag 

摘      要：This paper aims to investigate the dynamics of buoyancy-driven microflow in a narrow annular space inside a liquid floated gyroscope(LFG). Several theoretical models with a non-uniform thermal boundary for fluid flow in annular channels are given to analyze the effects of various parameters, such as the clearance size h, roughness height re, and rough density ε, on the flow and temperature profiles as well as on the fluid-drag torque. In the narrow annular regime, the relationship between the temperature and the angular displacement of the outer wall is defined as a cosine function, and the surface roughness of the inner wall is structured as a series of surface protrusions with a circular shape. With the increase of clearance size h, the flow velocity gradually increases to a stable level, and the drag torque increases initially and then decreases to a stable level. Furthermore, the increase of roughness height re and roughness density ε intensifies the frictional effect of fluid on the inner-wall surface. However, these two parameters have no significant effect on the flow velocity. This study can provide theoretical references for precision manufacturing and precision improvement of gyro instruments.