Papers by Author: Chiufeng Lin

Abstract: The performance of brushless permanent magnet motor for electric vehicle applications is simulated by commercial CFD codes Fluent 6.3. It is difficult to model motor winding area and to well pose the motor external boundary conditions for using CFD method. A possible approach to simplify the thermal resistance computation is to use an empirical equivalent thermal conductivity of the system winding impregnation and insulation. The empirical equivalent thermal conductivity is case sensitive and regressed in the experiment. The same is true for the boundary condition of motor. In this paper, we proposed a new model to compute equivalent thermal conductivity and overcome the above problem. This model takes advantage of the packing bed heat transfer model proposed by Zehner and Schlünder. Besides, the boundary conditions are also obtained by the numerical experiments. The validity of CFD method using in the present paper is validated utilizing the experimental data. The numerical data are concurred with the experimental data. As a result, the CFD method is shown to be a feasible method for modern thermal design for brushless permanent magnet motor.

Abstract: This paper presents an experimental investigation on the use of high-resolution injection techniques to deliver sample plugs within electrophoresis microchips. Two novel injection microfluidic chips are proposed, which employ conventional cross-shaped and U-shaped injection system combined with an expander to deliver high-quality sample plugs for detection in separation channel. The valving characteristics on microfluidic devices are controlled through appropriate manipulations of the electric potential strengths during the sample injection and separation steps. These novel injection techniques developed in this study has an exciting potential for use in high-quality, high-throughput chemical analysis applications and in many other applications throughout the field of micro-total-analysis systems.

Abstract: This paper proposes a numerical and experimental investigation of mixing behaviors of two liquid samples in microchannels that are shaped into different geometric barriers. The micro-mixers utilized in this study are fabricated on low-cost glass slides using a simple and reliable fabrication process. Samples are driven by a hydrodynamic pump to lead them into the mixing section of the microchannels. The effects of mixing performance of various kinds of barrier shape are discussed in this study. The numerical and experimental results show that a better mixing efficiency can be obtained in the microchannels while using the elliptic-shape barriers in compare with the leaking side-channels. In this study, the simulated and experimental results are in good agreement. The investigation of mixing efficiency in microchannels with different geometric barriers could be crucial for microfluidic systems.