Real liquid mixed systems

This review is devoted to inspection of the availablity of some most outstanding relationships between viscosity of real liquid mixed systems and the independent... 

From these correlations it would be natural to expect that the maximum blowoff velocity as a function of air-fuel ratio would occur at the stoichiometric mixture ratio. For premixed gaseous fuel-air systems, the maxima do occur at this mixture ratio, as shown in Fig. 4.56. However, in real systems liquid fuels are injected upstream of the bluff-body flame holder in order to allow for mixing. Results [60] for such liquid injection systems show that the maximum... 

The advantage of the two-phase micro flow contacting concept is easy phase separation, as the phases are never inter-mixed. However, in view of the normally facile separation of gases and liquids, this is not of major impact. A real large benefit stems from operating with gas and liquid layers of defined geometry with a knovm, defined interface, unlike most disperse systems having a size distribution of their bubbles in the continuous liquid. 

The Murphree efficiency EmV is only equal to the point efficiency Emv if the liquid on the plate is perfectly mixed. On a real plate this will not be so, and to estimate the plate efficiency from the point efficiency some means of estimating the degree of mixing is needed. The dimensionless Peclet number characterises the degree of mixing in a system. For a plate the Peclet number is given by ... 

Real world materials are not simple liquids or solids but are complex systems that can exhibit both liquid-like and solid-like behavior. This mixed response is known as viscoelasticity. Often the apparent dominance of elasticity or viscosity in a sample will be affected by the temperature or the time period of testing. Flow tests can derive viscosity values for complex fluids, but they shed light upon an elastic response only if a measure is made of normal stresses generated during shear. Creep tests can derive the contribution of elasticity in a sample response, and such tests are used in conjunction with dynamic testing to quantity viscoelastic behavior. 

The two extreme hypotheses on mixing produce lumped models for the fluid dynamic behavior, whereas real reactors show complex mixing patterns and thus gradients of composition and temperature. It is worthwhile to stress that the fluid dynamic behavior of real reactors strongly depends on their physical dimensions. Moreover, in ideal reactors the chemical reactions are supposed to occur in a single phase (gaseous or liquid), whereas real reactors are often multiphase systems. Two simple examples are the gas-liquid reactors, used to oxidize a reactant dissolved in a liquid solvent and the fermenters, where reactions take place within a solid biomass dispersed in a liquid phase. Real batch reactors are briefly discussed in Chap. 7, in the context of suggestions for future research work. 

Equations (6.1) and (6.2) pertain to ideal systems, that is, systems where there are no interactions between the molecules. In a real system the pressure effect on p. in the vapor phase has to be modified by a fugacity coefficient < >, and the effect of mixing on the chemical potential in the liquid phase has to be modified by an activity coefficient 7,. The more general expression for equilibrium (called the 4>-y representation) then becomes... 

The mutual solubility of liquids is also conditioned by the extent of inter-molecular action. Although ideally the mixing of liquids is a natural process accompanied by an increase in entropy, in real systems the heat of... 

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