In this research, a new ultrasonic operated valve was analyzed, prototyped, and tested for use in an abrasive viscous fluid application. The innovative valve concept is based on controlling the friction of material by employing several friction elements along the flow direction. Abrasive particles in the viscous fluid are stopped by the force of friction when coming into contact with the friction elements. Friction is neutralized by use of vibration to break away the abrasive particles from the friction element surfaces. Several factors were considered in designing the piezoelectric valve. Factor identification was done by conducting experiments and analyzing data. Some important factors that affect the valve design were recognized to be back pressure, size of friction blades along the direction of flow, density of material, viscosity, amplitude, frequency of vibration, and proportion of particles in the mix. First, a method was designed for measuring the friction coefficient of the given viscous materials. A design of experiment approach was pursued in order to identify the significant parameters. A piezoelectric transducer was used, which vibrated at the resonance frequency of 20 kHz. FEM modeling was used at that stage to ensure that the resonance frequency of the designed valve matched the resonance frequency of the transducer and booster that provided vibration. In order to perform proportional flow control, pulse width modulation was used to control the duty cycle of ultrasonic power transferred to the valve. A study was performed to find the best vibration performance for the parameters in the range of operation.
|Commitee:||Chen, Yong, Rosenbloom, Paul|
|School:||University of Southern California|
|Department:||Industrial and Systems Engineering|
|School Location:||United States -- California|
|Source:||DAI-B 70/05, Dissertation Abstracts International|
|Keywords:||Abrasive fluids, Piezoelectric valves, Ultrasonic, Vibration, Viscous fluids|
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