Effect of Mixture Fraction of Ethanol/Heptane Mixture on Spray Characteristics of Electrostatic Atomization

Abstract

The electrospray characteristics depend on liquid flow rate, applied voltage, electrode configuration and liquid properties such as electrical conductivity, surface tension and viscosity. This study experimentally investigated electrospray characteristics of binary liquid mixtures. The tested liquid was ethanol, which has relatively high electrical conductivity and low heating value as a liquid fuel, n-heptane, which has relatively low electrical conductivity and high heating value, and their mixtures. The electrical conductivity of the liquid mixture decreased rapidly with increasing heptane volume fraction for heptane volume fraction higher than 70 %. The electrospray characteristics for mixtures with heptane volume fraction less than 70 % were different from those with heptane volume fraction greater than 70 %. By increasing the applied voltage, the electrospray mode changed in the order as spindle, cone-jet and multijet below the heptane volume fraction of 70 %. For the heptane volume fraction of 90 %, however, the electrospray mode changed in the order as spindle, cone-jet, asymmetry cone-jet and plused jet. The onset voltage, over which the cone-jet mode appears, was decreased with increasing heptane volume fraction while heptane volume fraction was less than 70 %.