Ultrasound monitoring of bubble size and velocity in a fluid model using phased array transducer

Abstract

Experimental studies on composite materials highlighted the existence of gas bubbles (voids) at different scales (micro and macro).These voids, resulting from the fabrication process, are sources of weakness for the end-user material. Therefore, several studies focus on the evaluation and the minimization of void rate. During injection of resin into the fibrous matrix, bubbles appear. Some are dispersed while others persist and diminish the overall quality of the finished product. This study consists in detecting bubbles during the resin transfer molding (RTM) process using an original method based on ultrasound. However, in practice we have to face with several problems due to the heterogeneity of the environment, such as the differentiation of a bubble from a strand or fiber. Due to the complexity of the problem, an experimental setup was built in order to detect bubbles using an ultrasonic phased array transducer in a flow of viscous fluid only, without the presence of fiber matrix. The study deals with the flow of a model fluid, which simulates the injected resin, with presence of air bubbles trapped in a channel production. Since the ultrasonic characteristics of the experimental setup are well known and characterized, the number, velocity and size of air bubbles could be evaluated.

Monitoring the Cure State of Thermosetting Resins by Ultrasound

“…Since these irreversible changes occur at different rates and clearly affect the evolution of the resin mechanical properties, they can be easily detected by ultrasonic techniques [ 15 , 16 ]. Moreover, a relationship exists between the attenuation a and the dynamic viscosity η, allowing to differentiate the viscosity between two polymerization states [ 43 , 44 ].…”

A bubble detection system for propellant filling pipeline

“…9 The reflection coefficient equals to 1 means that nearly all the incident ultrasound will be reflected, but considering the shape of the bubble-water interface is spherical rather than plane, Eq. (1) is not quite accurate.…”

Monitoring of an ascending air bubble in a viscous fluid/fiber matrix medium using a phased array transducer

“…Then, the ultrasound characterization measurement procedure is presented. Thanks to waves reflected at the channel interfaces (oil/PMMA or oil/bubble) bubbles are detected and their sizes and velocities are quantified [10]. These results are compared with theoretical models and those obtained by video capture.…”