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Effect of Different Surface Microstructures in the Thermally Induced Self-Propulsion Phenomenon
Clint John Cortes Otic1, Shigeru Yonemura2
1Department of Finemechanics, Graduate School of Engineering, Tohoku University, 6-6 Aramaki Aza Aoba, Aoba-ku, Sendai 980-8579, Miyagi, Japan.
Micromachines
|June 24, 2022
Summary
Micro/nano-scale systems can generate propulsive forces using heated microstructures. Optimizing microstructure shape, like tip angle, significantly enhances this force, dependent on gas flow conditions.
Area of Science:
- Micro/nano-scale physics
- Thermally driven flows
- Molecular gas dynamics
Background:
- Objects near heated microstructured surfaces experience propulsive forces.
- These forces arise from momentum transfer by gas molecules.
- Thermally driven flows are also induced in such micro/nano-scale systems.
Purpose of the Study:
- Investigate propulsive forces on objects in micro/nano-scale systems.
- Analyze the impact of microstructural modifications on induced forces.
- Understand the relationship between microstructure geometry and force generation.
Main Methods:
- Utilized the direct simulation Monte Carlo (DSMC) method to simulate molecular gas flows.
- Modified conventional ratchet-shaped microstructures into various configurations.
- Analyzed the influence of parameters such as tip angle, Knudsen number, and temperature difference.
Main Results:
- Modifying microstructure configurations can significantly enhance propulsive force.
- The tip angle of the microstructure is a critical parameter for force optimization.
- Increased propulsive force is observed with decreasing tip angle.
- Force enhancement depends on Knudsen number and temperature difference.
Conclusions:
- Microstructure design is crucial for optimizing propulsive forces in micro/nano-scale systems.
- Decreasing the tip angle of microstructures enhances the propulsive force.
- The study provides insights into the formation and enhancement mechanisms of thermally induced forces.
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