Sergejus Borodinas

Minimizing heat generation in a piezoelectric Langevin transducer

High power Langevin piezoelectric transducers have large dielectric and piezoelectric losses. Most of these losses are converted into accumulating internal heat that increases the temperature of the transducer. In this paper we analyze how to minimize heat generation and reduce temperature of the transducer. The modification of transducer design is proposed by separating piezoceramic elements and adding a metal block between the elements. Analytical and numerical modeling of the Langevin transducer was carried out to find the dependence of the oscillation amplitudes and temperatures on the location of the separated piezoceramic elements and thermal properties of the additional metal part. Two prototypes of the Langevin transducer with two different locations of the piezoceramic elements were fabricated. Measurements of the vibration amplitudes of the contact point and temperature distribution along the transducers were done. Measurement results are compared with the numerical results.

Compound Piezomechanical Systems of Algae Cell Disrupting

Abstract One of the most attractive sources of raw materials for biofuel production can be algae oil processing into biofuels. In this paper, the authors are proposing a unique ultrasonic piezoelectric system, which would allow the reduction of internal energy losses and concentration of ultrasonic energy into a small closed volume. The current vibrating systems whose ultrasonic energy is concentrated inside of a hollow cylinder where the water–algae mixture is flowing. The ultrasonic energy is concentrated in a local volume to create a high-power bubble implosion process. Two, three or multiple ultrasonic composite systems to concentrate the total energy into a hollow cylinder in order to create a strong algae cell ultrasonication are used. The experiments and the numerical finite element method (FEM) analysis results using the proposed transducers as well as the biological test results on algae cell disruption by ultra-sonication are presented in this paper.

Piezoelectric Actuator Based on Two Bending-Type Langevin Transducers

Abstract Langevin-type piezoelectric transducers are widely used for different industrial applications such as high-accuracy positioning, ultrasonic welding, bonding, drilling, etc. Usually Langevin-type transducers operate at longitudinal mode by employing d33 vibrations of piezoceramic elements. A novel design of piezoelectric actuator based on two bending-type Langevin transducers is introduced. Two half-wavelength transducers are connected by a special aluminum plate. Piezoceramic rings with two-directional polarizations are used for bending oscillation excitation. An input voltage with phase shifted by π/2 on different transducers is applied. The forward and backward elliptical motion of the contact tip is controlled by changing phases of electric signals on different transducers. A numerical simulation was carried out to investigate the trajectories of contact point motion and to validate the operating principle of the actuator. Experimental prototype of the piezoelectric actuator was fabricated, and the measurements of driven tip movements and mechanical output were performed. The results of numerical and experimental analysis are discussed.

Piezo Pump Disruptor for Algae Cell Wall Ultrasonication

Abstract It is well known that green algae cells are used for bio-fuel production. There are a few known ways of how to process algae cells for oil extraction – chemical and mechanical. Ultrasonic cavitation is one example of mechanical processing that is in use. Longitudinal ultrasonic systems are used for this purpose. In a proposed system the flow of an algae–liquid mixture is created by means of the ultrasonic capillary effect, thus the transducer is the only energy consumer which now acts as a homogenizer (disruptor) and a pump at the same time. What is important is that the capillary is located nearby the strong cavitation field which decreases the chance of unprocessed algae cells flowing into the secondary reservoir. Numerical and comparative tests are done and presented in this paper. The main results are presented in figures and tables, all advantages of the system are outlined in the conclusion section.

Ultrasonic cavitations research in thin flowing liquid layer

Automatic systems are widely integrated at dangerous application fields under unsafe environment for safety reason or to change the monotonous human work by robotic systems. Modern standards are rising higher for modern equipment so the maintenance of such equipment must be at the same level. In this paper the ultrasonic cleaning system for sloping surfaces is proposed. Current system is self turning and rain-triggered and can be perfectly used for solar panels or roof windows cleaning. The ultrasonic wave imparts directly on a film of fluid no more than a few millimeters thick on the surface. The proposed system has low power consumption and does not require any maintenance itself. The prototype of proposed system is developed in our laboratory.

V-mode Piezomotor Using Flexural Bending Mode

The earlier “butterfly” type piezomotor (5 × 5 × 6 mm size) developed by authors had a driving force up to 0.5 N. Two identical resonators with a bending-type vibration were joined to one “shaking beam” system for generating an elliptical trajectory of the actuator’s contact point. The researchers at Korean Institute of Science and Technology have improved the contacting elements of the motor and increased the driving force up to 3 N. In the present work, research on increasing the driving force of the motor was continued. The research proceeded in three directions: optimization of the actuator’s eigenmode, optimization of the contacting layer (actuator-driving element) and a determination of the best fixing points of the actuator to the motor’s base. To estimate the characteristics of the current piezomotor, a three-dimensional numerical FEM analysis using ANSYS, was performed. The validity of analysis was confirmed by comparing the experimental results with the numerical ones. As a result of the research, a flat piezoelectrical linear motor with a driving force up to 20 N was fabricated. The mechanical characteristics of the proposed piezomotor are presented in this paper.