Wang Qiang, Wang Zhen
Infrastructure Management Department, Wuhan University of Technology, Wuhan 430070, China.
Hubei Key Laboratory of Theory and Application of Advanced Materials Mechanics, Department of Mechanics and Engineering Structure, Wuhan University of Technology, Wuhan 430070, China.
Micromachines (Basel). 2022 Jul 18;13(7):1134. doi: 10.3390/mi13071134.
Micromotors have spread widely in order to meet the needs of new applications, including cell operation, drug delivery, biosensing, precise surgery and environmental decontamination, due to their small size, low energy consumption and large propelling power, especially the newly designed multifunctional micromotors that combine many extra shape features in one device. Features such as rod-like receptors, dendritic biosensors and ball-like catalyzing enzymes are added to the outer surface of the tubular micromotor during fabrication to perform their special mission. However, the structural optimization of motion performance is still unclear. The main factor restricting the motion performance of the micromotors is the drag forces. The complex geometry of a micromotor makes its dynamic behavior more complicated in a fluid environment. This study aimed to design the optimum structure of tubular micromotors with minimum drag forces and obtain the magnitude of drag forces considering both the internal and external fluids of the micromotors. By using the computational fluid dynamics software Fluent 18.0 (ANSYS), the drag force and the drag coefficient of different conical micromotors were calculated. Moreover, the influence of the Reynolds numbers Re, the semi-cone angle δ and the ratios ξ and η on the drag coefficient was analyzed. The results show the drag force monotonically increased with Reynolds numbers Re and the ratio η. The extreme point of the drag curve is reached when the semi-cone angle δ is 8° and the ratio ξ is 3.846. This work provides theoretical support and guidance for optimizing the design and development of conical micromotors.
由于尺寸小、能耗低和推进力大，微电机已广泛应用于细胞操作、药物递送、生物传感、精确手术和环境净化等新应用领域，特别是新设计的多功能微电机，它在一个装置中结合了许多额外的形状特征。在制造过程中，诸如棒状受体、树枝状生物传感器和球状催化酶等特征被添加到管状微电机的外表面，以执行其特殊任务。然而，运动性能的结构优化仍不明确。限制微电机运动性能的主要因素是阻力。微电机复杂的几何形状使其在流体环境中的动态行为更加复杂。本研究旨在设计具有最小阻力的管状微电机的最佳结构，并考虑微电机的内部和外部流体来获得阻力的大小。通过使用计算流体动力学软件Fluent 18.0（ANSYS），计算了不同锥形微电机的阻力和阻力系数。此外，分析了雷诺数Re、半锥角δ以及比率ξ和η对阻力系数的影响。结果表明，阻力随雷诺数Re和比率η单调增加。当半锥角δ为8°且比率ξ为3.846时，达到阻力曲线的极值点。这项工作为优化锥形微电机的设计和开发提供了理论支持和指导。
