Jet streams

Each vent device discharge pipe is extended into the vessel and its end is fitted with a deflector device. This disperses the jet stream of solids (catalyst) and liquids discharged and dissipates this force, which should otheiwise be exerted on the vessel wall immediately opposite. 

The reaction turbine, shown schematically in Figure 2-2, is generally more efficient. In its primary (stationary) nozzles only half the pressure energy of the gas stream is converted to velocity. The rotor with a blade speed matching the full-jetted stream velocity receives this jetted gas stream. In the rotor blades the other half of the pressure energy is used to jet the gas backward out of the rotor and, hence, to exhaust. Because half the pressure drop is taken across the rotor, a seat must be created around the periphery of the rotor to contain this pressure. Also, the pressure difference across the rotor acts on the full rotor area and creates a large thrust load on the shaft. 

Fig. 17-27. Average position and strength of the jet stream in January between 11 and 14 km above the earth s surface (speeds are in m s ). Source After Battan (1).

Entrainment velocity The velocity in a jet stream that effectively entrains the dust or gas particles that surround it. 

Local air velocity The air velocity in the zone in which the design conditions have to be met. Or, the air velocity recorded at a specific location in a space or in a jet stream. 

Tlie importance of when to correct/replace a broken bag will depend on tlie type of collector and tlie resultant effect on outlet emissions. In inside bag collection types of collectors, it is very important tliat dust leaks be stopped as quickly as possible to prevent adjacent bags from being abraded by jet streams of dust emitting from tlie broken bag. Tliis is called tlie domino effect of bag failure. Outside bag collection systems do not liave tliis problem, and tlie speed of repair is delennined by wlietlier tlie outlet opacity litis e.xceeded its limits. Often, it will take several broken bags to create an opacity problem mid a convenient maintenance schedule can be employed instead of emergency maintenance. ... 

The maximum Q/P for a circular jet is at X = 17.1 Dq (Refs. [9, 21]) or in other words the optimum jet origin diameter is 1/17.1 of the distance desired for effective entrainment. Since the entrainment efficiency does not fall off too rapidly, it is not necessary to use only the ratio given, but rather to stay in close proximity, say 25-35 percent. Large diameter jet streams are more effective for the same power than small streams [17]. Data on flat blade turbines has not been fully evaluated. 

The tropical regions of both of the hemispheres troposphere exhibit easterly flow called the trade winds. Finally the jet stream -sometimes described as a river of air - flows at mid-latitude of both hemispheres with velocities of 25 to 50 m/sec from west to east, often carrying material completely around the Earth at its altitude close to the tropopause. It is in this flow that balloonists attempt to circle the globe. 

Electroorganic synthesis will be covered in section 4.5.4. It is appropriate, however, to make a reference here to the role of u/s in electroorganic processes. Atobe et al. (2000) have reported the effect of u/s in the reduction of acrylonitrile and mixtures of acrylonitrile and methyl acrylate. The selectivity for adiponitrile in the reduction of acrylonitrile was significantly increased under u/s irradiation with a power intensity over the u/s cavitation threshold ( 600 cm ). This favourable influence of u/s can be attributed to the improved mass transfer of acrylonitrile to the electrode interface by the cavitational high-speed jet-stream. 

Gold sulphide had a featureless non-crystalline plain surface with very sharp and smooth edges of the dried mass. However, the smoothness of the surface was destroyed completely with blisters appearing as a result of cavitation, after 30 min of ultrasound irradiation. A closer look at the surface at x 7,500 magnification reveals extensive surface erosion as a result of the micro-jets streaming. 

The finest particles composed of fine silt and clay are carried over much larger distances (Fig. 1.6). Using oxygen isotopes of aeolian quartz, it has been shown that significant quantities of dust with an average diameter of 1-10 microns are transported by jet streams from desert zones over the rest of the world. Eolian admixtures have been referred to explain the presence of Si02 in soils developed in non-quartz-containing volcanic rocks in Hawaii and Israel. 

Attempts to obtain regular spherical shaped particles by spray drying were unsuccessful. Apparently, collisions of not completely solidified particles in the jet stream supplying primary droplets into the drying chamber result in their coalescence and/or distortion of shape. The perspective of obtaining microspheres with well-controlled shape, diameter, and diameter... 

It seems reasonable to note that the micro-jet stream generated by the ultrasonic cavitation promotes mass transport. Such an effect was discussed for proton transport in aqueous solutions (Atobe et al. 1999). Understandably, a proton moves in the solution as a hydrated particle. Nevertheless, we should pay attention on the similarity between proton and electron, in the sense that both are essentially quantum particles. A solvated electron, therefore, can be considered as a species that is similar to a hydrated proton. Hence, the micro-jet stream can promote electron transfer. 

Houcine et al. (64) used a non-intrusive laser-induced fluorescence method to study the mechanisms of mixing in a 20 dm CSTR with removable baffles, a conical bottom, a mechanical stirrer, and two incoming liquid jet streams. Under certain conditions, they observed an interaction between the flow induced by the stirrer and the incoming jets, which led to oscillations of the jet stream with a period of several seconds and corresponding switching of the recirculation flow between several metastable macroscopic patterns. These jet feedstream oscillations or intermittencies could strongly influence the kinetics of fast reactions, such as precipitation. The authors used dimensional analysis to demonstrate that the intermittence phenomenon would be less problematic in larger CSTRs. 

During each winter rainy season, meteorological alert was established after each of the Chinese nuclear weapons tests October 1966, December 1966, and December 1967. The criteria used to alert the collection network of a forecasted storm system included the presence of a well-defined jet stream and a forecast for precipitation in excess of 3 mm. over a majority of the sampling sites. 

---