The use of an electric field to control the formation of small drops at an orifice in a circular disk was investigated. Water drops were formed in a pure cyclohexane continuous phase, in the pre-jetting regime using four different orifice diameters. Because of the application of high potentials (up to 1000 V/cm) and because the orifice plate produced a nonuniform field, drop volumes varied to as little as 20 times smaller than the drop volume for a zero-field case. The drops were ellipsoidal in shape, and droplet eccentricity increased dramatically with field intensity. A mathematical model was developed, based on the potential field between a disk (the orifice plate) and an infinite plate (the grounded screen). The electric force on the drop was calculated from the field intensity at discrete points around the periphery. Values for predicted drop volumes using this model and for experimental drop volumes agreed very well.
NASA STI/Recon Technical Report N
- Pub Date:
- Drop Size;
- Electric Fields;
- Mathematical Models;
- Particle Size Distribution;
- Fluid Mechanics and Heat Transfer