Degree of mixing

Effect of Different Decrees ofNlixing. Once Eqq is evaluated on the basis of A/, and N- using equation 87, it has to be translated into Ey by considering the degree of mixing on the tray. It is obvious that for a small plate with completely backmixed Hquid,... 

The degree of mixing is described as variation coefficient standard deviation, X is fraction of additive, andX is average fraction of... 

Care should be taken to avoid mixing too long, as in some cases this will result in a poorer blend. A graph of degree of mixing versus time should be made to selecl the proper mixing time quantitatively. 

There have been many modifications of this idealized model to account for variables such as the freezing rate and the degree of mix-ingin the liquid phase. For example, Burton et al. [J. Chem. Phy.s., 21, 1987 (1953)] reasoned that the solid rejects solute faster than it can diffuse into the bulk liquid. They proposed that the effect of the freezing rate and stirring could be explained hy the diffusion of solute through a stagnant film next to the solid interface. Their theoiy resulted in an expression for an effective distribution coefficient k f which could be used in Eq. (22-2) instead of k. 

If the gas is to be intimately dispersed in the liquid, the input power to the mixer will be several times the gas power level for the gas. In other words, the mixer power level must be compared to the gas power level to be certain that the required degree of mixing is achieved. 

Time refers to the retention time or residence which is the length of time that an organic is at the appropriate oxidation temperature. Roughly, if a 95% destruction efficiency is required, a residence time of a half a second is adequate. That is, the organic compound is brought up to a temperature of about 1400° F, and maintained at that temperature for a retention time of half a second. Both retention time and turbulence must be achieved, where turbulence is a term which implies a required degree of mixing. If the turbulence occurs and if the 1400° F for a half a second is... 

To determine if the local supply air reaches the breathing zone, a tracer gas is used. The tracer concentrations at various heights below the supply unit are recorded as a percentage of the supply duct tracer concentration. This provides information on the degree of mixing taking place between the and ambient air. 

Mixing factor A factor used in air distribution relating to the actual degree of mixing that takes place between the room air and a contaminant generated in that room. 

Gas constant (J/mol K) coarse particle radius Specific weight of feed Degree of mixing Time scale (s)... 

Exponent in scale-up equation, describing type/degree of mixing required, Eigure 5-32, or number of samples in statistics Number of impellers Number of tube baffles (vertical)... 

Sakata [180] evaluates the degree of mixing of the liquid as it flows across a tray and its effect on the tray efficiency, Figure 8-30. For plug flow the liquid flows across the tray with no mixing, while for partial or spot mixing as it flow s over the tray, an improved tray efficiency can be expected. For a completely mixed tray liquid, the point efficiency for a small element of the tray, Eog> tray efficiency, E V, are equal. 

From Figure 8-31 the effect of mixed and unmixed pools of liquid can be noted. For a completely mixed tray, there is no concentration gradient from inlet to outlet, and therefore the entire tray has a uniform composition. The degree of mixing across the tray as determined by the number of discrete mixing pools on the tray has an effect on the relationship between Eqg E y as a function of X. 

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