Measuring bench for investigation of mixing process in ultrasonic mass-transfer apparatus
In the article the laboratory measuring equipment for investigation of mixing in the ultrasonic mass-transfer apparatus is described. The experimental results of testing the equipment during dissolving of crystalline substance in liquid medium with the help of high-intensity ultrasonic vibrations are considered.
Cavitation produced by Ultrasonics
The problem of cavitation produced by ultrasonic vibration is examined theoretically. Equations are developed which describe the motion of a gas-filled cavitation bubble in a liquid medium subjected to alternating pressure; the case of an empty cavity is also considered Information is obtained concerning the distribution of fluid pressures and velocities in the medium near the bubble surface during the motion It is suggested that these theoretical conclusions may be used to show how the intensity of the various effects of cavitation will depend on ultrasonic frequency and intensity. In particular, it is predicted that all cavitation phenomena will diminish and finally disappear as the frequency is raised The important part played by the nucler from which the cavitation bubbles grow is emphasized.
A New Vacuum Pressure Infiltration CFRP Method and Preparation Experimental Study of Composite
In order to prepare a carbon-fiber-reinforced polymer composite (CFRP) with ideal microstructure and properties, a new vacuum pressure infiltration CFRP method is proposed based on an analysis of existing CFRP preparation process methods. Research on composite material preparation systems was carried out by using this new method principle. The system mainly includes a fiber pre-forming module, a vacuum heating infiltration module, a hot-press curing molding module, and a data acquisition control module. Under the conditions of natural curing at 0 MPa + 6 h + 25 °C, vacuum heating curing at –0.05 MPa + 30 min + 80 °C, and hot-press curing at 0.7 MPa + 5 min + 50 °C, a two-dimensional (2D) CFRP with excellent microstructure and properties was successfully prepared. Observing the microstructure of the prepared composite material, it can be found that the inside of the composite material was sufficiently and uniformly infiltrated, and common preparation defects such as holes and delamination were effectively controlled. Through the performance test, the bending strength of the material reached 790 MPa.