Multi-Jet Mode Electrospray for Non-Conducting Fluids Using Two Fluids and a Coaxial Grooved Nozzle

Figures & data

FIG. 1 Schematic diagram of (a) the experimental set-up and (b) the nozzle geometry.

TABLE 1 Physical properties of the fluids

Fluid	Viscosity (cP = mPaS) ^a	Surface tension (dyn/cm = mN/m) ^a	Conductivity (μS/m) ^a
Ethanol	1.074	21.97	10.6
Olive oil	82.2	32.36	0.1

FIG. 2 Spray visualization. (a) Q_ethanol = 4ml/h, Q_{olive oil} = 12ml/h; (b) Q_ethanol = 4ml/h, Q_{olive oil} = 16 ml/h; (c) Q_ethanol = 4ml/h, Q_{olive oil} = 20ml/h; (d) Q_ethanol = 6ml/h, Q_{olive oil} = 18ml/h; (e) Q_ethanol = 6ml/h, Q_{olive oil} = 24ml/h; (f) Q_ethanol = 6ml/h, Q_{olive oil} = 30ml/h.

FIG. 3 The meniscus of the Taylor cone consisted of two liquid layers: (a) Q_ethanol = 4ml/h, Q_{olive oil} = 12ml/h; (b) Q_ethanol = 6ml/h, Q_{olive oil} = 18ml/h.

FIG. 4 Functioning domain for multi-jet mode spraying.

FIG. 5 Current versus voltage for multi-jet operation. (a) Qethanol = 4ml/h, Qolive oil = 12ml/h; (b) Qethanol = 6ml/h, Qolive oil = 18ml/h.

FIG. 6 Current as a function of the flow rates of the outer (non-conducting) fluid.

FIG. 7 Real-time size distribution of the droplets.

TABLE 2 Geometric mean diameter and geometric standard deviation of the droplets

Flow rate of ethanol (ml/h)	Flow rate of olive oil (ml/h)	Flow rate of total liquid(ml/h)	Geometric mean diameter (μm)	Geometric standard deviation
4	12	16	21.57	1.15
4	16	20	24.69	1.13
4	20	24	29.44	1.14
6	18	24	29.29	1.11
6	24	30	34.26	1.12
6	30	36	43.15	1.13