The thermostated medical jet nebulizer: Aerosol characteristics.

The sudden expansion of gas at the outlet of the jet (pneumatic) nebulizer significantly reduces the temperature of the solution, which may provoke bronchospasm, therefore it is recommended to use modern pneumatic inhalers equipped with a thermostat or a universal thermal attachment that allow to obtain a higher temperature aerosol, i.e. thermo-aerosol. The research was carried out for model Newtonian fluids. The droplet diameters of the aerosol spray were investigated using a Spraytec aerosol particle size measurement system. Analysis of the obtained results showed that the increase in solution viscosity caused a decrease in mean droplet diameters and prolonged nebulization time. The analysis of experimental data made it possible to propose a correlation equation describing the mean diameter of the droplets depending on the properties of the liquid and the flow conditions in the thermostated medical nebulizer. The obtained data contributes to a better understanding of the complex liquid atomisation process and can be helpful in the design of medical nebulizers and pharmaceutical preparations.

The effect of shear and extensional viscosities on atomization of Newtonian and non-Newtonian fluids in ultrasonic inhaler.

The paper contains results of the experimental study on atomization process of aqueous solutions of glycerol and aqueous solutions of glycerol-polyacrylamide (Rokrysol WF1) in an ultrasonic inhaler. In experiments the different concentration aqueous solutions of glycerol and glycerol-polyacrylamide have been tested. The results have been obtained by the use of laser diffraction technique. The differences between characteristics of ultrasonic atomization for test liquids have been observed. The analysis of drop size histograms shows that the different sizes of drops have been formed during atomization process. The present study confirmed the previous reports which suggested that the drops size changes with the increase in viscosity of solution changes in spray characteristics were also observed. It has been shown that the shear and extensional viscosities affect the process of atomization.