Therefore, the term discharge coefficient was introduced in these investigations. The discharge coefficient is the ratio of the mass flow rate at the discharge end of the nozzle to that of an ideal nozzle. The discharge coefficient as a function of injection pressure and temperature is shown in Figure 3(a), where a decreasing trend was observed in the discharge coefficient with Ruxolitinib structure an injection pressure for all tested nozzles. With rise in injection temperature, initially it gave an incremental trend and then reached to a steady state above 50��C similar to mass flow rate and mean flow velocity. It was predicted that the FC-3 nozzle had the lowest discharge coefficient followed by FC-3.5 and FC-2. Figure 3(a) Discharge coefficient as a function of temperature, (b) Spray width as a function of temperature.

Normally, partial evaporation of the liquids in the system is stimulated by introduction of thermal energy below the liquid boiling point. The obtained vapor contents depend on the process parameters like, the degree of heating, pressure, and nozzle geometry. When the liquid is discharged into the surrounding environment with a phase inversion, the jet disintegration takes place, and the vapor phase inside the nozzle supports the disintegration process [10]. Therefore, in comparison with highly pressurized atomization, uniform spray patterns came out with a steadily increasing spray width as shown in Figure 3(b) and constant spherical droplet size distribution owing to the small droplet diameters. In these studies, an increment trend in spray width with temperature was more prominent at 1bar pressure.

This behavior strengthens the concept of liquid heating for improved atomization rather than subjecting very high load pressures. By doing so, the gas phase additives can be omitted due to availability of the vapor phase in spraying medium. By observing the mass flow rate and mean flow velocity as an integral parameter of the airless spray process, the occurrences inside the atomizer can also be investigated. From the images in Figure 2, the overall heat assisted atomization was regarded as efficient and pressure moderated. Apart from the parameters discussed so far, the other flow regimes can also be achieved by use of hot liquids as spraying media [11]. The most critical spray parameters involve the liquid flow within the atomizer and the interaction between the liquid jet and the ambient air.

The liquid flow within the actuator and atomizers can be described by dimensionless quantities called Weber and Reynolds Entinostat numbers. Figures 4(a) and 4(b) showed a monotonic increase both in Weber and Reynolds numbers which lead to an improved atomization and macroscopic spray cone length. The Reynolds number determines whether the liquid flow was dominated by inertial or viscous forces and hence either the flow was laminar or turbulent.