Session: 04-01 Numerical and Data Based Methods for Multiphase Flows

Paper Number: 86873

86873 - Design Optimization of Laser-Induced Bubble for Highly Efficient Generation of Microjets 

Tagawa et al. proposed a device that generates high-speed microjets from the meniscus by generating laser-induced bubbles with pressure waves in a microtubule partially filled with liquid. This device is expected to be applied to a variety of devices such as needleless syringes and inkjet printing. However, the generation of high-speed jets requires a high-power laser system on the order of milli-joules, and it is necessary to establish an efficient injection method. In this study, we optimized the placement and bubble size of the laser-induced bubbles that drive the microjet. In the optimization, we used Covariance Matrix Adaptation Evolution Strategy, which is one of the evolutionary algorithms. And a compressible multiphase flow solver based on Allaire's 5-equation model was used to evaluate the solution. In the optimization, the impulse that determines the jet velocity is maximized to reduce the simulation cost. Furthermore, data mining using correlation analysis and dimensionality reduction algorithms was used to extract features related to microjet generation. Optimization showed that it is effective to generate laser-induced bubbles near the tube wall. Data mining extracted features and revealed that the fewer bubbles the better, that there is a bubble volume that maximizes impulse, and that there is a strong positive correlation between bubble expansion and impulse. These results from optimization and data mining are important for producing high-speed jets at low energy.

Presenting Author: Tatsumasa Ishikawa Tokyo University of Agriculture and Technology