Spray morphology

Table 16.5 Spray morphology at nozzle outlet, water, and picture size = 35 mm x 35 mm...

Table 16.6 Spray morphology without and with enclosure hollow cone nozzle, D = 2 mm, PVP K90 4 wt% a = 25 mm...

Spray morphologies of mannitol sprays with different solids concentratimis are shown in Table 16.8. Higher mannitol concentration does not yield visual spray morphology differences. This can be attributed to the fact that the difference between shear viscosities, occurring under subcooled conditions, do not apply for superheated liquids. As can be seen in Fig. 16.8, the shear viscosities of mannitol solutions are lowered for higher liquid temperatures. In addition, the shear viscosity values for different mannitol concentrations are getting more similar. 

To analyze the liquid fragmentation process of the PVP model solutions, a commercial lab-scale twin-fluid atomizer (Fig. 19.4) and the hot gas nozzle are used. The two atomizers mainly differ in their prefilming mechanism and the air-liquid ratio. Table 19.3 provides a brief overview of the atomizer parameters. The key parameter in this spray morphology study is the atomizer gas pressure, chosen that an optimum of the spray disintegration is foimd. The liquid feed rate and other parameters are kept constant during the experiments. The lab-scale atomizer is operated at a pressure of 5 bar absolute. 

To capture the spray morphology and even single droplets and filaments shadowgraphy has been utilized (Fig. 19.5). A CCD camera records two shadow... 

Spray drying 0.05 to 0.5 Low Morphology of spray dried powders can Instant foods, dyes, detergents, ceramics... 

Fig. 33. Ni-Cr-Zn pla.sma spray coating on D6AC steel showing complex morphology ideal for adhesive bonding [155].

Guiot, P., Baudhuin, P., and Gotfredsen, C. (1980). Morphological characterization of liposome suspensions by stereological analysis of freeze fracture replicas from spray frozen samples, J. Microsc., 120, 159-174. 

Figure 14.2. Ultrasonic spray deposited CuInSe2 film for photovoltaic applications using mixed-metal organic precursors. XRD shows (left) the growth of nearly phase pure CuInSe2, and optical micrographs show reasonable morphologies (right).

PCA [Precipitation with a compressed anti-solvent] A process for making a solid with unusual morphology by spraying a solution of it into a supercritical fluid. The process resembles spray drying into a supercritical fluid. Used for making microspheres, microporous fibers, and hollow microporous fibers. 

FIGURE 6.3 (a) Morphology of ball-milled NiO and SDC powders produced separately and (b) NiO-SDC composite powders coproduced by spray pyrolysis, showing a possible mechanism by which the composite powders retain a higher surface area resulting in a higher performance [19]. Reprinted from [19] with permission from Elsevier. 

ZnO particle morphologies are very complex and diversiform in comparison with Ti02. Thus, monodispersed ZnO particles with well-defined morphological characteristics, such as spherical, ellipsoidal, needle, prismatic, and rod-like shapes, have been obtained. Aggregates composed of these basic shape particles have also been achieved. The methods used for synthesis of these ZnO powders include alkali precipitation [214-216], thermal decomposition [217], hydrothermal synthesis [218], organo-zinc hydrolysis [219], spray pyrolysis [220], and other routes. 

During spraying, the carbon substrate is moved by means of an X-Y axes coordinated system controlled by computer software. The CLs formed from the electrospray technique show both morphological and structural improvements, which could contribute to better catalyst utilization than is achieved... 

---