Sylwia Włodarczak

The effect of shear and extensional viscosity on atomization in medical inhaler.

The paper contains the results of experimental studies of water, aqueous solutions of glycerol and aqueous solutions of glycerol-polyethylene oxide (PEO) atomization process in a medical inhaler obtained by the use of the digital microphotography method. The effect of the shear and extensional viscosity on the drop size, drop size histogram and mean drop diameter has been analyzed. The obtained results have shown that the drop size increases with the increase in shear and extensional viscosity of liquid atomized. Extensional viscosity has a greater impact on the spraying process. It has been shown that the change in liquid viscosity leads to significant changes in drop size distribution. The correlation for Sauter mean diameter as function of the shear and extensional viscosity was proposed.

The modified swirl sedimentation tanks for water purification.

This paper discusses design, evaluation, and application for the use of swirl/vortex technologies as liquid purification system. A study was performed using modified swirl sedimentation tanks. The vortex separators (OW, OWK, OWR and OWKR) have been studied under laboratory conditions at liquid flow rate from 2.8⋅10-5 to 5.1⋅10-4 [m3/s]. The pressure drop and the efficiency of purification of liquid stream were analyzed. The suspended particles of different diameters were successfully removed from liquid with the application of swirl chambers of proposed constructions. It was found that damming of liquid in the tank increases alongside liquid stream at the inlet and depends on the tank construction. The efficiency of the sedimentation tanks increases alongside the diameters of solid particles and decrease in the liquid flow rate. The best construction proved to be the OWR sedimentation tank due to smallest liquid damming, even at high flow rates, and the highest efficiency of the purification liquid stream for solid particles of the smallest diameter. The proposed solution is an alternative to the classical constructions of sedimentation tanks.

Atomizers with the Swirl Motion Phenomenon

The liquid atomization is very important and widespread process in many branches of industry and in agriculture. The technology development, better construction solutions to improve atomization process for the specific application are searched for. Depending on the assignment on which the atomizer is to be used, there are different requirements. Atomization itself doesn’t mean that the process proceeds in a correct and that performance of the spray system is optimum. The application of the effervescent atomizer witch swirl motion phenomenon improves of atomization process compared to pressure-swirl or effervescent atomizers, affects aerosol quality, improves atomization process and ensures its optimization. The spray parameters are influence by many factors: geometric dimensions, liquid properties and operational conditions. The dimensions of atomizer outlet, mixing chamber, aerator have the most important impact on the atomization process. Viscosity and surface tension affect Sauter mean diameter. Viscosity also affects spray angle, while the significant influence of the surface tension on the spray angle has not been shown.

Selected Aspects of Dust Removal from Gas Stream for Chamber Separators

Dust occurring in the atmospheric air constitutes a difficult and important matter within environmental protection. Consequently, the relevant solutions aiming to eliminate or reduce the emissions of such pollutants are being sought for. It is implemented by the application of the relevant exhaust gases purification installations as well as by controlling the dust emissions. While selecting or designing the dust removal devices one should consider the estimated quantities and types of dusts, the places of their intended usage, material durability, tightness of connections. In the course of numerous production processes it is necessary to use precise, multi-stage air purification. In order to perform the preliminary dust removal, the simplest devices, like gravity settling chambers, can be successfully applied. The following chapter presents the theoretical fundamentals of dust removal process as well as the methods for dust removal from the air and exhaust gases taking advantage of various physical mechanisms. On top of that, designing solutions for the devices applied to dust removal are going to be presented so are the outcomes of the research regarding the modernisation of a classic chamber separator. The attempts included the changes in the design by replacing a cuboidal chamber with a cylindrical one. In order to intensify the process, swirl motion phenomenon has been taken advantage of. This allowed to obtain satisfactory efficiency values by using a set of basic physical phenomena.

Design and Study of Conical Pressure-Swirl Atomizers

The paper shows the results of experimental studies for two-phase swirl atomizers with two inlet ports different in terms of design. The effect of volumetric liquid and gas flow rate and the height and diameter of mixing chamber on the discharge coefficients, histograms, radial distributions of mean droplet diameters in the drop stream and the mean Sauter diameter were determined. The studies were conducted within the air flow rates not exceeding 5.6·10−4 [m3/s] and water flow rate 1.11·10−5 [m3/s]. It was shown that the discharge coefficient increases with the higher Reynolds number for the liquid and decreases with the higher gas flow rate. The increased liquid flow rate caused greater drop diameters and increased gas flow rate allowed to obtain droplets with smaller sizes. The value of Sauter means that the diameter is dependent on the ratio of height to the diameter of mixing chamber. The rapid increase in the mean droplet diameter occurs above the value of H S /D S ≈ 2.75. It was further noted that higher gas flow rate within the aerosol axis gives rise to the drops with smaller diameters and there is a clear difference in the size of droplets between the central stream area and its edges. In addition, the empirical correlation was proposed for the discharge coefficient as a function of work characteristics and geometric dimensions of the atomizer. The obtained data can be used for designing new atomizers and are essential from the viewpoint of agriculture or combustion processes.

Light and Heavy Pollutant Removal by Modified Swirl Sedimentation Tank – Design and Study

The paper shows the effect of volumetric flow rate of liquid and diameters of solid particles in the sedimentation tank for the water contaminated with sediment and oil substances on the effectiveness of the tank. The effect of liquid flow rate on liquid damming has been studied. It has been shown that the liquid damming in the tank increases with increasing a volumetric flow rate of liquid at the inlet. The determined value of the loss coefficient is 3.06. The effectiveness of sedimentation tank for heavy fraction increases with the diameter of solid particles. It has been shown that an increase in the liquid flow rate reduces the effectiveness of the tank, both for the heavy and the light fractions. The vortex sedimentation tank of the proposed construction allows for the simultaneous removal of the heavy and light fractions from water and their partial separation.

The analysis of pneumatic atomization of Newtonian and non-Newtonian fluids for different medical nebulizers

Abstract Objective: The article contains results of the experimental studies on atomization process of inhaled drugs and aqueous solutions of glycerol with aqueous solutions of glycerol polyacrylamide (Rokrysol WF1) in pneumatic nebulizers. In experiments, the different concentration of aqueous solutions of glycerol polyacrylamide have been tested. In addition, the effect of nebulizer design on atomization process has been determined. The one of the main elements of medical pneumatic nebulizer is nebulizer cup. Significance: The experiment with this scope is new and is very important from the point of view of aerosol therapy. Methods: The results have been obtained by the use of the digital microphotography technique. In order to determine a physicochemical properties of tested liquids, a rheological measurements and measurements of the surface tension were carried out. Results: The differences between characteristics of aerosol for the liquids have been observed. The analysis of the droplets size distributions shows that the different diameters of droplets for Newtonian and non-Newtonian fluids have been formed during atomization in pneumatic nebulizers equipped with different nebulizer cups. The effect of the mouthpiece location on the droplets diameters has been shown. Conclusions: Precise design of nebulizer and nebulizer cups, and also physicochemical properties of atomized liquids are of high importance in order to the effectiveness of drug delivery to patient’s respiratory tracts.