Enhancing the bubble collapse energy using the electrohydrodynamic force

Abstract

The energy released during the bubble collapse process is used for medical and industrial purposes. The present study investigates the effects of electrohydrodynamic force on the collapse phenomenon near the rigid wall and the enhancement of the collapse energy. A solver in the OpenFoam open-source code is developed based on the volume-of-fluid model, in which the effects of compressibility, energy transfer, and electrohydrodynamic force are included. The developed solver is validated against the available experimental data, and a good agreement is seen. The effects of an electric field on the bubble collapse for the range of the electrocapillary number (CaE) of 0–5.76 and normalized wall distance (γ) of 0.8–2.0 are investigated. The results indicate that the bubble is deformed due to the presence of an electric field, and the values obtained for the maximum velocity and pressure are 33 and 35 times the state without the electric field at γ = 2 and CaE = 5.76, respectively. Also, due to the increase in velocity, the maximum shear stress on the rigid wall is increased up to seven times in the absence of the electric field. Therefore, the jet force obtained from the bubble collapse can be enhanced by applying the electric field in the continuous phase fluid. Also, the correlations are proposed to estimate the jet velocity, pressure, and wall shear stress of bubble collapse in the presence of an electric field.