Browsing by Author "Cheng, Jia-Hong"

Now showing 1 - 2 of 2

DESIGN OF MARINE VEHICLE POWERED BY MAGNETOHYDRODYNAMIC THRUSTER
(2020-01-01)
Chan, Cherng-Shyong
;
Cheng, Jia-Hong
;
Zeng, Cing-Hui
;
Huang, Jen-Rung
;
Chen, Yu-Hsuan
The present study outlines the design of a magnetohydrodynamic (MHD) thruster system which is capable to power a 3-meter ship model cruising at a speed of V = 0.5 m/s using the Lorentz force generated by the electric field and magnetic field in conducting seawater. Based on the computational fluid dynamics (CFD) simulation of a modified Delft 372 catamaran model, the thrust needed to achieve the targeted cruising speed is first estimated. To achieve the estimated magnitude of the thrust, dimensions of thruster modules are designed based on numerical simulations of magnetic field, for better distributions of the strength and uniformity of the magnetic field. Additional CFD simulations of the flows through the thruster module, coupled with magnetic and electric fields, are conducted to realize the hydrodynamics. Consequently, several configurations of thruster modules are manufactured and experimented. A particular configuration of a shielded two-unit module is chosen to power the ship model. Finally, a complete system of MHD-1 marine vehicle, including a ship model, multiple MHD thruster modules and power suppliers, is assembled and tested. The system is shown capable to cruise closely to the targeted speed.
Interaction of two magnetic micro-chains in a rotating field
(2020-01-01)
Cheng, Jia-Hong
;
Lin, Chih-Ru
;
Chen, Ching-Yao
;
機械工程學系
;
Department of Mechanical Engineering
Interactions between two chains consisted of micro-sized magnetic beads are experimentally investigated. Driven by a rotating field, three distinct modes of magnetic interactions are identified, referred to as chaining, locking and transit. The two chains gradually approach to form a longer chain in the chaining mode. The locking mode refers the chains undergo an interesting orbital-like circular motion, which mimics a binary star system. The chains could also evolve from locking to chaining in the transit mode. A necessary criterion for a locking mode is derived, which agrees excellently with the correspondent experiments.