Zuo Chuncheng

Analysis of electroosmotic flow with linear variable zeta potential

The electroosmotic flow induced by an applied potential through microchannels between two parallel plates is analyzed in this study. A 2D Poisson-Boltzmann equation is used to model the electrical double layer (EDL), and the 2D modified Navier-Stokes equation which includes the body force caused by the interaction between the charge density and the applied electrical potential field is also used. These coupled equations are numerically solved with a finite difference method. The detailed results indicate that, in general, the essence of the zeta potential effect on the feature of EOF is significant and clear. The traits of electroosmotic flow with uniform, step change, especially linear variable zeta potential are discussed.

Simulation on electroosmotic flow through a rectangular microchannel with different aspect ratios

A numerical study of electroosmotic flow through microchannels has been completed in this paper. A 2D Poisson-Boltzmann equation and a 2D Navier-Stokes equation governing the electric double layer (EDL) field and velocity field in the cross section of rectangular microchannels are numerically solved by employing SIMPLE method without the use of Debye-Huckel approximation. The volumetric flowrate with different aspect ratios for a fixed hydraulic diameter are compared. The comparison of the numerical simulation results show that significant influences of the channel cross-section geometry (i.e. the aspect ratio) on flow field. The objective of this paper is to provide the basis for electroosmotic pumping.

Adaptive predictive control of grain drying process parameters

To ensure the quality of the dried grain and improve the intelligent level in drying process, the automatic control system for grain drying machine is developed. Based on virtual instrument and predictive control, the system can automatically detect moisture content and temperature, calibrate moisture sensor, detect faults and alarm, automatically control the air temperature and predictive control the discharging speed of grain, etc. It has advantages such as strong adaptive capacity, a high degree of automation and simple operation. The actual application shows that it can meet the requirements of the actual drying operation, effectively control the stability of the grain moisture, improve the dry food quality and reduce the energy consumption.

Study on Friction Coefficient of Liquid Flow through a Rectangular Microchannel with Electrokinetic Effects

The influences of the electrical double layer(EDL) field near a solid-liquid interface and induced electro kinetic field on pressure-driven liquid flow through micro channels are analyzed. The equation governing the EDL field in the cross section of rectangular channels is a nonlinear, two-dimensional Poisson–Boltzmann equation. A body force caused by the EDL field and induced electro kinetic field is considered in the equation of motion. The governing equations are numerically solved with the use of a finite control volume scheme. The electro kinetic effects on the flow velocity and the friction coefficient for the micro channel are discussed. The results show that the flow velocity in micro channel predicted by the model with electro kinetic effect is lower than that predicted by the the macro scale fluid theory (without electro kinetic effect). The friction coefficients predicted by the model with electro kinetic effect were found to be higher than that predicted by the macro scale fluid theory. It is different from that the friction coefficient predicted by the macro scale fluid theory for a rectangular channel is dependently only on the aspect ratio (H/W). The friction coefficient of the micro scale liquid flow is influenced by the ionic concentration of the liquid, the zeta potential and the size of micro channels. The friction coefficient increases as the ionic concentration of the aqueous solution decreases in the same micro channel. And stronger deviations were observed as the hydraulic diameter decreases with the same aspect ratio.

Numerical Simulation on Electroosmotic Flow in a Rectangular Microchannel

Computer simulations of electroosmotic flow through rectangular microchannels have been completed in this paper. A 2D Poisson-Boltzmann equation and a 2D Navier-Stokes equation governing the electric double layer (EDL) field and velocity field in the cross section of rectangular microchannels are numerically solved by employing a finite control volume scheme without the use of Debye-Huckel approximation. The numerical solutions show the influences of the channel cross-section geometry (i.e. the aspect ratio), channel size, the ionic concentration and the applied electrical field strength on the volumetric flowrate and the average velocity. And the numerical simulation results show significant influences of the channel cross-section geometry on the volumetric flowrate. Also, the numerical simulation results show that the volumetric flowrate increased with the square of hydraulic diameter. However, increases in hydraulic diameter have little impact on the average velocity. The objective of this paper is to provide the basis for electroosmotic pumping