Two-phase zone

Many experimental studies of entrainment have been made, but few of them have been made under actual distillation conditions. The studies are often questionable because they are hmited to the air-water system, and they do not use a realistic method for collecting and measuring the amount of entrainment. It is clear that the dominant variable affecting entrainment is gas velocity through the two-phase zone on the plate. Mechanisms of entrainment generation are discussed in the subsection Liquid-in-Gas Dispersions. ... 

Class 1—hydrate layer underlain by two-phase zone of mobile gas and water... 

Component or petroleum fraction, MW Two-phase zone Critical temperature, °F Single-phase zone Pressure, atm temperature, °F 1.0 100 1.0 100 600 600 1000 1000 ... 

Enthalpy value is in the two-phase zone. In the 1.0-atm column, the value is the saturated vapor enthalpy. In the 100.0-atm column, the value is the saturated liquid enthalpy. 

Unlike preceding cases, the broad fine-grained two-phase zone, 2 mm thick, is formed at the interface between a 20 mass % Fe-80 mass % Ni alloy and the saturated aluminium melt (Fig. 5.16e). The same applies to a 15 mass % Fe-85 mass % Ni alloy, the thickness of the two-phase zone being 1.7 mm. The FeNiAl9 compound is dominant in the two-phase zone. Its fine crystals form a framework whose pores are filled with an aluminium solid solution. The NiAl3 inclusions are relatively seldom. 

As seen in Fig. 5.16f, the most complicated microstructure is formed between a 10 mass% Fe-90 mass % Ni alloy and the aluminium melt saturated with the alloy constituents. The compact one-phase intermetallic layer adjacent to the alloy base is about 8 pm thick. The next layer, 20+5 pm thick, is also compact. Then, the broad (around 300 pm) two-phase zone is observed. Microhardness value is 1.9 GPa for the alloy base and 0.88 GPa for the aluminium matrix. Intermetallic layers were too thin to... 

Next, we can translate the origin of x to 8g, and then by integrating over the two-phase zone, we will have... 

Let us consider some results of numerical simulation for = 50 ps. Fig. 1 shows the evolution of semiconductor surface temperature at different exposure power density Wo. Once the surface temperature has exceeded the melting point Tm, the near surface layer starts to melt and the two-phase transition zone moving into semiconductor (Fig. 2). In the case of high Wo, the surface temperature rises nearly linearly after the two-phase zone has formed with %-dependent coefficient. Both for silicon and germanium, the surface temperature stops rising and falls down at the time approximately 90 ps after CPF action onset. 

Figure 2 Schematic representation of Winsor-type equilibria in a ternary amphiphilic system. Between the water-oil side of the phase triangle and the base of the three-phase triangle there is a narrow two-phase zone at very low surfactant content that corresponds to the equilibrium between the excess phases that contain very little amounts of surfactant (about the critical micelle concentration). (From Ref 34.)...

Ju et al. [2] found evidence of two kinds of unsteady flow boiling for 21 parallel microchannels measuring 231 x 713 pm. They observed in their parallel microchannel array either a global fluctuation of the whole two-phase zone for all the microchannels (Fig. 1) or chaotic fluctuations of the two-phase zone (Fig. 2) overpressure in one microchannel and under-pressure in another. The individual microchannel mass flow rate was not controlled. 

For increasing heat fluxes, the N-shape is more and more pronounced. Dark points in Fig. 12 of [8] represent a steady flow, whereas the white points are for an unsteady flow. A mean heat transfer coefficient is deduced. Introducing the Stanton number, we compare the heat flux transferred to the fluid with the heat transported with the fluid. If we only consider the operating conditions which satisfy a two-phase zone mainly in the minichannel (Fig. 8 of [9]), a heat transfer scaling law appears (Eq. 8). Thus it is possible to predict a mean heat transfer coefficient when a two-phase zone is mainly inside the minichannel ... 

For long-tube vertical natural circulation evaporators the heat-transfer coefficient is more difficult to predict, since there is a nonboiling zone in the bottom of the tubes and a boiling zone in the top. The length of the nonboiling zone depends on the heat transfer in the two zones and the pressure drop in the boiling two-phase zone. The film heat-transfer... 

Between type I and II eases, an intermediate diagram with a biphasic zone with horizontal tie lines could be expected. Such an occurrence does happen with some amphiphiles like alcohols, but not generally for surfactants, in which case a type 111 diagram and phase behavior is exhibited instead (23). Though it lks much more complex than the two previous ones, type 111 diagram is no exception and cun be found in tnany systems. The polyphasic region passes.ses a three-phase zone surrounded by three two-phase zones according to Schreinemaker s rule of alternation (20,24). 

Equation 9.47 implies that to conserve the quasi-equilibrium on the two-phase zone-fi phase boundary, a diffusion path should go through c, and then the system will not choose a concentration in phases 1, 2, but their fractions on the interphase (pi, pi) piR (p2R = 1-Pir) and piL are the places where the diffusion path comes into a two-phase region and leaves it. 

Here only Regime III is possible (formation and growth of a two-phase zone (Figure 9.10d)). 

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