Zhaoying Zhou

Numerical Simulation of Turbine Flowmeter's Three-Dimensional Flow Fields

DN 15mm turbine meters flow fields were simulated with CFD software FLUENT. Flow fields show that meters pressure loss is influenced by front-end and tail-end shapes, and radius of flow conditioner hub, the thickness of flow conditioner blades and rotor blades. There are vortices in gaps in front and back of rotor hub. And flow conditioner blades affect the intensity of vortex. Flow fields near rotor blades are uneven, for the wake flow of upstream flow conditioner blades. The rotation of rotor affects flow fields closely in front and back of it. There is not visible flow separation at suction side of rotor blades. Some advices to optimizing meters design were given. The method for predicting meter factor and performance curve with CFD software was put forward. The accuracy of meter factor calculated by CFD software is able to better than 2%

Experimental Study on Turbine flowmeter's Performance Measuring Fluids with Different Viscosities

In order to understand the law of the change of turbine meters performance according to fluid viscosity variation, experimental study on DN15 mm meters was made with water, diesel oil and solution of methyl cellulose as the medium for test. The ability of adaptivity to viscosity change was test on turbine meters with solid hub, barrel hub and hollow hub rotor. Results show that the ability of adaptivity to fluid viscosity change can be improved if solid hub or hollow hub rotor is adopted, but turbine meters sensitivity to viscosity variation cannot be reduced by great extent with the optimization of rotor hub

Electrical impedance microchip using microelectrodes

Taking advantage of MEMS (micro electromechanical system) techniques, a microfabricated electrical impedance (EI) chip with microelectrodes was designed and fabricated. The microchip with Ti/Pt/Au detection microelectrodes and Su-8 sample reservoir was realized form glass substrate. The completed micro-electric impedance devices were characterized with NaCl solutions, cell culture solution RPMI1640 and K562 leucocythemica lymphocyte solution over the frequency range of 1 K Hz to 51 KHz. Impedance spectra from 10 Hz to 50 KHz measured in hela cells and transfected hela cells were distinct and demonstrated the ability to be beneficial in evaluating the cell transfection process, which gives an potential application field of electrical impedance microchip.

Study on the fuzzy control technique for the power ultrasonic instrument

The nccessity of having the functions of the fiequency tracking automatically and the vibration amplitude control in the power ultrasonic vibration system is summarized in the paper. The approaches of the frequency tracking automatically by using a self-optimizing fuzzy control and the vibration amplitude control based on a self-modifying PID fuzzy controller in the power ultrasonic instrument are presented. The principles and stmctures of two fuzzy controllers are analyzed, and the design procedure is introduced in details. The experiments show that the robustness and the control accuracy of the system are improved by using these fuvy control techniques. A novel means of the vibration control in the power ultrasonic system is offered.

The identification of frequency domain model of ultrasonic vibration system

The identification of frequency domain model of ultrasonic vibration system by using least square method is discussed. The key frequency band is subdivided, in order to keep characteristic point of system invariability. An actual vibrating body is checked up, and the model coincides with the experiment result well. This identifying model can be extensively applied to many fields.