Three-stream nozzle

Figure 12.14 presents a schematic of the spray-drying system for con-tact-sorption drying of bacterial preparations, while the design of a three-stream nozzle used to disperse solid sorbent within the spray of these preparations is shown in Figure 12.15. Performance data of this nozzle are given in Table 12.2, and characteristics of contact-sorption drying for selected bacterial cultures are specified in Table 12.3.

RGURE 12.15 Three-stream nozzle for dispersing particulate sorbent within the liquid spray. (From Anon., 1990.)... 

P 5] Layers of 4,4 -bipyridyl (0.3 mol 1 in dichloromethane), ethyl bromoacetate (0.3 mol in dichloromethane) and a separation layer of dichloromethane were fitted into each other by means of a concentric separation mixer (three-fluid nozzle with three tubes having diameters of 1.5, 3 and 4 mm, slotted into each other) [78]. Thereby, two circular liquid layers of a thickness of 200 pm and a center stream of 1.5 mm diameter were generated. The reaction temperature was 22 °C. The reaction solution was inserted as droplets or a continuous stream either directly or via... 

Spheres, spheroids, and horizontal pressure vessels should be actively protected with cooling water at an application rate shown in Table 8-13 over the entire tank surface including the structural supports and the underside of the tank, including leg area. Adequate coverage should also be provided for the ends of horizontal vessels. This may be accomplished by a water spray, water distribution weirs, monitors or combination of all three. Monitor nozzles and manual hose streams should be provided to supplement the fixed water spray fire protection on the vessel. 

The three different nozzles have slight differences in the configuration of the liquid insert and air cap (the path for the atomizing air), but the largest difference is in the size of the annulus between these components to permit the higher volume of compressed air to flow at the same atomizing pressures for atomization of the liquid stream (Fig. 18). 

In a cross-flow configuration, one stream with one fluid enters from the left and two streams carrying the same other fluid are fed from above and below [112]. The latter have much larger flow rates as the first stream so that this layer is hydro-dynamically compressed when all three streams enter the outlet channel on the right side of the cross. The channel which carries the stream to be focused narrows to a kind of nozzle when approaching the T-junchon... 

A recent development is the Uhde [532] three-stream burner with an adjustable tip. A portion of the of oxygen enters through the center nozzle, the remainder through the outer annulus, the oil is fed through the inner annulus. The center oxygen nozzle also accommodates the preheat burner. This combi-burner concept avoids the change from preheat burner to process burner in the start-up phase, a cumbersome procedure necessary when using the traditional two-stream Texaco burner. As tested in a demonstration plant the carbon conversion could be increased to better than 99.6%, which means a reduction soot formation by a factor better than 5. 

Kenzakowski, D. C., and S. M. Dash. 2000. Study of three-stream laboratory jets with passive mixing enhancements for noise reduction. AIAA Paper No. 2000-0219. Kenzakowski, D. C., and S. M. Dash. 1998. Advances in jet aircraft mixer/nozzle and plume simulation. JANNAF 6th SPIRITS User Group Proceedings. NASA Kennedy Space Center, FL. 

Table 12.2 Characteristics of a Three-Stream Pneumatic Nozzle...

Another type of kinetic energy nozzle is the three-fluid nozzle. The spray characteristics obtained by two- and three-fluid nozzles are similar when atomizing low-viscosity feeds at up to intermediate feed rates. Use of the second air stream with three-fluid nozzles causes a waste of energy, except for high feed rates of low-viscosity feeds. 

The precise location of the feed point will affect the number of stages required for a specified separation and the subsequent operation of the column. As a general rule, the feed should enter the column at the point that gives the best match between the feed composition (vapour and liquid if two phases) and the vapour and liquid streams in the column. In practice, it is wise to provide two or three feed-point nozzles located round the predicted feed point to allow for uncertainties in the design calculations and data, and possible changes in the feed composition after start-up. 

In the second configuration (moderate swirl) tested (see Fig. 20.2a), only the air stream was forced and no liquid-fuel pulsations were imposed. The experiments were performed with a Parker-Hannifan Research Simplex Atomizer. The atomizing nozzle consisted of a primary liquid ethanol feed with a coaxial primary air stream. The air stream passed through a set honeycomb, flow-straightener, and swirl vanes to provide the necessary level of swirl. Three loudspeakers were used to excite the primary air. 

As discussed earlier, with a nozzle of 70 pm and a stream moving at 10 m/s, our system is committed to a vibration frequency of about 30,000 cycles per second (30 kHz) in order to get drops to form. If we prefer a margin of safety, we may want to charge and sort three drops at a time in that case, we will want a particle in no more than every third drop. This means that our total particle flow rate can be no faster than 10,000 particles per second. Because cells are not spaced absolutely evenly in the flow stream (they obey a Poisson distribution), most sorting operators like to have particles separated by about 10-15 empty drops. With a 70 pm nozzle and a stream velocity of 10 m/s, this restricts our total particle flow rate to about 2000-3000 particles per second. For sorting cells of very low frequency within a mixed population, this may involve unacceptably long sorting times. 

A version of our apparatus for the study of gas uptake and the measurement of mass accommodation coefficients is shown m Figure 1. The apparatus consists of three chambers. A highly controlled stream of droplets is produced in the first chamber with a nozzle vibrated by a piezoelectric ceramic oscillator. About 100,000 droplets are produced per second. The radius of the droplets is typically 60 microns and the droplets travel at about 3000 centimeters per second. 

For any spraying operation, it is necessary to specify the amount of toxicant required per unit area, the volume of liquid per unit area, and the drop size. To control these, the operator has three main variables at his command—operating pressure, nozzle size and type, and phase ratio of the emulsion. Each has some effect on all the factors specified. In addition, in aerial spraying the orientation of the nozzles in the air stream may also be varied to control drop size. 

The three component streams are in a recycle mode at the desired flow rates before foaming. During foaming, surfactant and precursor are premixed before they come in contact with the polyisocyanate in the power mixer. The foaming mixture is then discharged through multiple nozzles in the spreader (Figure 5). 

The object of atomization is to produce a large number of small droplets from a liquid stream so that the droplets can be dried into particles. Atomization is accomplished usually by one of three t3q)es of devices (1) a high-pressure nozzle, (2) a two-fluid nozzle, or (3) Airspeed centrifugal discs. These atomizers are low in cost, produce broad... 

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