Sprays experiments

Savage, E. F., and Cowart, F. F., Georgia Expt. Station, Report of 1949 Spraying Experiments... 

One set of good spray experiments was also conducted by Dr. Norm Akesson and reported in 1979 and 1982. (5,6). Table VII... 

For the production of fine dispersed PEG by expanding CCb-saturated solutions the initial guess indicates that the starting conditions should be near the liquefaction curve in order to allow to reach the solid-gas region after the expansion. This is further illustrated by the spraying experiments. 

How to Use You can buy essential herbal oils and dilute them with water to make sprays. Experiment with proportions, starting with a few drops of oil per cup of water. 

To grow ZnO films on sapphire, Shiosaki et al. [236] used ZnCF as a precursor for classical CVD and ZnO in combination with Br2 and H2 for chemical transport. ZnCU was evaporated at about 550 °C and deposited at 900 °C. ZnCl2 was also used as a source for spray experiments [237, 238]. Ristov et al. [238] investigated different solutions for spray pyrolysis of ZnO films, using aqueous solutions of ZnCl2, (NH4)Zn02, Na2Zn02, and Zn(OH)2 as sources for zinc. 

Liquid water uptake of CrOg-treated wood was decreased to that observed after treatment of wood with a water repellent. This decrease in liquid water uptake was found for treated flat-grained and vertical-grained surfaces, but not for end-grain wood, a result indicating that capillary uptake could still occur. Water repellency was observed in both water-immersion and water-spray experiments. Preliminary studies on CrOs-treated wood surfaces using ESCA showed that Cr was reduced to Cr at concentrations of 1.25% chromium. The reduction undoubtedly plays a role in the fixation of Cr on the wood surface. 

Universally employable spraying experience required large-scale series coating... 

Arcoumanis C, Chang J-C (1993) Heat transfer between a heated plate and an impinging transient diesel spray. Experiments in Fluids 16 105-119. 

The effectiveness of a spray system in removing fission product iodine from the containment atmosphere depends on several parameters, as is known from early investigations, among others those conducted by Row et al. (1969), by Patterson and Humphries (1969) and by Row (1971). Other experiments have demonstrated that spray solutions buffered at pH 9.5 are more effective in iodine removal by a factor of 3 than pure water, probably because acidification of the outer droplet layer is prevented which, in pure water, may be caused by the I2 hydrolysis and disproportionation reactions (Hyder, 1991). Other parameters controlling iodine removal by sprays are specific for the individual system under consideration (internal geometry, spray rate etc.). Spraying experiments performed in the context of the CSE tests (see Section 7.3.3.3.8.) showed a reduction of the airborne iodine concentration of more than one order of magnitude within a spray time of about 10 minutes subsequent spray periods were much less effective (Hilliard and Postma, 1981). In the case of airborne particulate iodide, the chemical composition of the spray solution (water, boric acid, alkaline borate solution) does not affect... 

The crystallinity of the PVP particles increases when temperature and humidity are lowered. Needle-like structured PVP particle surfaces obtained at low temperature and low rel. humidity showed the same particle morphology as that received obtained in spraying experiments [26]. However, it was found that crystalline structures can also occur due to a crystallized initiator. Until now, it has not yet been possible to distinguish between crystallized product and crystallized initiator. 

Deionized water was taken as a model substance for the spray experiments as well as for investigations of flow regimes of gas-eiuiched liquids. 

A detailed knowledge about the release of the CO2 is indispensable for the evaluation of the spray experiments. Spray experiments with undersaturated and saturated solutions shall clarify the effect of the CO2 on the spray formation. Therefore, it has to be known under which conditions the outgassing of the CO2 occurs. 

The following figures show an overview of some representable results gained from the experiments with flat jet nozzles. For the experiments three substances were used. They are water, PEG 6000 (representing a pure polymer), and aqueous solutions of PVP K 30. The spray patterns of the untreated substances are compared to spray patterns of C02-enriched substances. The C02-enriched substances were sprayed in form of undersaturated solutions and in form of gas-saturated solutions. The flat jet spray experiments of water and PEG 6000 were carried out within the scope of subproject in Chapter 15 (Weidner, Ilieva). 

The above-mentioned spray experiments were also done with the polymer PEG 6000. Thereby, the spray forming geometries and parameters were the same as for water. In Fig. 7.13, an overview of the resulting spray patterns is shown. 

The pilot scale plant was used to perform spray experiments with an excess of CO2. There is a continuous flow of CO2. The liquid which shall be atomized is added cyclic with a piston pump. Therefore, it is assumed that the flow regime in and upstream the nozzle is a two phase flow consisting of a compressed gas phase and a gas-enriched liquid phase. This flow regime equals to the flow regime of a flash atomization with internal flashing. The optically transparent capillary with an inner diameter of 1 x 10 m is assembled to the pilot scale plant to analyze the flow regime and to verify these assumptions. 

Table 7.1 Parameters and results of elected spray experiments on pilot scale plant...

Cao, Z. M., Nishino, K., Mizuno, S., Torii, K. (2000). PIV measurement of internal structure of diesel fuel spray. Experiments in Fluids, 29(1), S211-S219. 

During tests of the LamRot in spray experiments, a broader drop size distribution was observed compared to the expectation from Rayleigh s breakup theory [6, 14]. This is especially evident for high-speed operation. In Fig. 22.2, photos... 

Fig. 22.2 Laminar operating rotary atomizer during spray experiments with viscous PVP solution. The flow rate is 201/h. In both cases, laminar conditions of the open channel flow are present. The reshaping from the open channel flow into the cylindrical thread is visible close to the LamRot edge. In (a), 3000 rpm are applied and the threads break up by axisymmetric disturbances. Higher rotary speed of 4000 rpm (b) leads to a more irregular break up obviously influenced by the ambient gas [14]...

Until now, the effect is not explicitly described in literature. Based on experiences during spray experiments with the LamRot, the question of whether the cross-wind flow leads to an increase in mean drop size and in span value of the drop size distribution has to be answered. In case of confirmation, the results of the similarity trials on the thread breakup in the field of gravity could help to find better design of the gas distributor for a spray drying process with the laminar operating rotary atomizer. The span value of the dried product is the main objective as it is the crucial quality feature of the spray drying process. The optimized process could be applied to produce high qualitative products, e.g. for pharmaceuticals, chemicals, or food materials. 

The gas distributor was built in form of a PMMA model in the scale 2 3. This model was to investigate the drop size distribution during spray experiments. After the successful application at the model, a gas distributor for the spray drying tower was built with metal sheets. A detailed drawing of the dimension is attached to [11]. The geometry is adapted to the dimensions of the spray tower and its accessories. Two fans and heaters are available for the hot air supply. These fans are able to realize flow rates of Fax lOOOm /h and Fswiri.max 700m /h. The swirl flow fan is frequency controlled. An additional frequency controlled fan is placed behind cyclone and the pocket filter to adjust the pressure in the spray tower at about —10 < Ap < —5 mbar. The temperatures of the air streams depend on the flow rate... 

The removal efficiency of the films from the surface is a function of the energy provided by precipitation and the chemistry of the impervious surface. Labencki et al. (in preparation) found that 98% of the PAHs in films were washed off of PTFE or Teflon in a controlled spray experiment versus 66-92% for PVC, asphalt, brick, and concrete surfaces (Figure 19.5). Diamond et al. (2000) and Eckley et al. (2008) found that 70-80% of several groups of SOCs and mercury in films, respectively, washed off of window glass. In contrast, Labencki et al. (in preparation) measured on 10-14% removal efficiency of the PAHs ITom window glass. Eckley et al. (2008) found that removal efficiency is related to angle of the impervious surface, and thus. 

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