New viscosity measurement technique by using rotational breakup of electrostatically levitated droplet

Abstract

New viscosity measurement technique by using rotational breakup of electrostatically levitated droplet was developed. The new one-dimensional viscosity measurement equation is derived by integrating three-dimensional momentum equation based on the assumptions with axisymmetric shape and internal flow of levitated droplet. From the measurement result obtained, internal flow around the center of the dumbbell shape droplet is axisymmetric along the elongational axis. This result means that the present proposed new method is appropriate. In the present study, high accuracy image processing technique is applied to obtain the shape and curvature around the center of the dumbbell shape droplet by using the transformation to rotating coordinate system. The present technique can be applicable after the breakup start and before the shape of the droplet becomes asymmetric. This is reason why Euler force becomes so large that the symmetricity cannot be sustained. The newly proposed viscosity measurement technique makes it possible to estimate the viscosity within 10 % error in the range of the viscosity which the previous levitation technique cannot be available.

Keywords

• viscosity measurement technique
• rotational breakup
• electrostatically levitated droplet
• containerless