Jetting regime

There are many contradictoiy reports about the jet regime, and theory, although helpful (see, for example, Siberman, loc. cit.), is as yet unable to describe the phenomena obsei ved. The correlation of Kumar et al. (Fig. 14-92) is recommended for air-hquid systems. 

Figure 10 Schematic presentation of the liquid jet regime boundaries effect of the density ratio.

To separate the surface lifetime from the total time interval between subsequent bubbles an approximation of the dead time according to geometric parameters of capillary and bubble volume was derived Fainerman Lylyk (1982) and Fainerman (1990). A substantial improvement for the exact determination of surface lifetime and its calculation was carried out by Fainerman (1992) who defined a critical point in the experimental curve in co-ordinates "pressure-gas flow rate". This point corresponds to a change in the flow regime from individual bubble formation to a gas jet regime. The calculation of the so-called effective age the surface (effective adsorption time) from the bubble surface lifetime was discussed by different authors ... 

Three operational regimes can be identified the squeezing, the dripping, and the jetting regimes. 

In the case of axisymmetric devices, the control of instability generating the transition from dripping to jetting regime is the basis of operation of this t) e of device. 

The principle behind this drop formation in jetting regime can be easily understood following the aforementioned theory.Any perturbation in the jet will result in a slightly thinner region. 

This required intensive turbulent mixing of liquid flows in apparatus, large specific surface for improving of external heat removal, jet regime under reaction with easy controlled reagents residence time Tr, that are possible under tha use of apparatus of novel generation - compact tubular turbulent reactors for effective carrying out of reaction of a-olefines sulfation by sulfuric acid at conditions of... 

We now discuss that in the jetting regime radius selection is dominated by simple hydrodynamics [46]. We assume that the shear stress and the velocity difference across the membrane can be neglected. For the analysis of the hydrodynamic flow profile, we can hence focus on the fluid motion inside and outside of the tube. In the experiments shown in Figure 11.10, the outer silicate solution is confined to a glass cylinder of radius J cyi(l-1 cm)- Along its central axis, buoyant cupric sulfate solution ascends as a cyHndrical jet of radius R. The cylindrically symmetric velocity fields v(r), which solve the Navier-Stokes equations, are... 

Different Jetting Regimes Observed in Fluidized Beds... 

Different jetting regimes were observed experimentally by different researchers using different bed configurations, different bed materials, and different operating conditions (see review by Massimilla, 1985). 

Ruzicka MC, Drahos J, Zahradnik J, Thomas NH. Intermittent transition from bubbling to jetting regime in gas-liquid two phase flows. Int J Multiphase Flow... 

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