Scaling Up Test Results

Scaling Up Test Results The results of small-scale tests are determined as dry weight of sohds or volume of filtrate per unit of area per cycle. This quantity multiplied by the number of cycles per day permits the calculation of either the filter area reqiiired for a stipulated daily capacity or the daily capacity of a specified plant filter. The scaled-up filtration area should be increased by 25 percent as a factor of uncertainty. In the calculation of cycle length, proper account must be made of the downtime of a batch filter. 

Whilst Izod tests are, perhaps surprisingly, generally reproducible it has been found impossible to scale up the results and thus predict the energy required to break a bar of large cross-section from results obtained with a bar of smaller cross-section. This has led to some uncertainty in the method of quoting results and the following approaches are used ... 

In critical cases of substantial economic importance, it may be advisable to perform flow tests—Q against A P—in lines of moderate size and to scale up the results to plant size, without necessarily trying to fit one of the accepted models. Among the effects that may not be accounted for by such models are time... 

Cellular foam occurs at low vapor velocities in small columns, where the wall provides foam stabilization. It occurs with some systems or tray designs but not with others and is promoted by surface tension effects such as the Marangoni effect (99). Cellular foam is uncommon in industrial columns. The foam that causes problems in industrial installations is mobile foam, where the bubbles are in turbulent motion. Mobile foam is associated with the froth and emulsion regimes. Cellular foam is encountered in bench-scale and pilot-scale columns. If cellular foam occurs in the test unit, caution is required when scaling up the results. 

The study shed new light on the importance of dynamic interaction between flow structures and pulsed sprays in liquid-fueled ACC. The results provided valuable information on the fuel injection timing for desired outcome. In the present case, the fuel injection timing that was synchronized with the air vortex shedding led to the suppression of pressure oscillations. When the fuel injection timing was delayed a quarter cycle after the vortex shedding, combustor pressure oscillations reached the highest amplitude. The scale-up test revealed a critical role of the relative amount of modulated heat release from pulsed fuel injection. 

Numerous publications in the 1960s and 1970s dealt in detail with the description of the mechanism, equilibrium, and kinetics of the uranium sorption reaction on titanium hydroxide [163]. Scaled-up testing of uranium sorption from seawater was carried out in the Soviet Union, United States of America, Great Britain, and Germany. The results were used in the design and construction of units for uranium recovery approximately 10-100 g of uranium were produced per year [180,181]. 

Figure 9 Results of scale-up tests with 6-in. column of ASB-2 resin, 14 cycles of spent brine reuse with chloride make-up, downflow cocurrent regeneration. (From Ref. 3.)...

Derivation of the correct scaling laws constitutes a necessary first step in an experimental study. The similitude relationships are essential for interpreting the experimental data and also for scaling up the results to real prototypes. There are two ways to scale up the model test results as shown in Fig. 26.2. The first is to use standard tables (look-up approach) for scaling the model observations by pertinent factors to predict the prototype response. The alternative is to study the underlying mechanics/physics of the problem based on the model tests recognizing that not aU the interaction mechanisms can be scaled accurately in a particular test. Once the mechanics/physics of the problem are identified in terms of pertinent dimensionless... 

Final. selection of diyer From the results of the diying tests and quotations, the final selection of the most suitable dryer can be made. A recent article describing diyer scale-up methodology in the... 

Usually, however, it is not feasible to establi a stage or overall efficiency or a leaching rate index (e.g., overall coefficient) without testing small-scale models of likely apparatus. In fact, the results of such tests may have to be scaled up empirically, without explicit evaluation of rate or quasi-equilibrium indices. 

When using dimensional analysis in computing or predicting performance based on tests performed on smaller-scale units, it is not physically possible to keep all parameters constant. The variation of the final results will depend on the scale-up factor and the difference in the fluid medium. It is important in any type of dimensionless study to understand the limit of the parameters and that the geometrical scale-up of similar parameters must remain constant. 

Scale-up techniques for using the results of pilot plant or bench scale test w ork to establish the equivalent process results for a commercial or large scale plant mixing system design require careful specialized considerations and usually are best handled by the mixer manufacturer s specialist. The methods to accomplish scale-up will vary considerably, depending on whether the actual operation is one of blending, chemical reaction tvith product concentrations, gas dispersions, heat transfer, solids suspensions, or others. 

While obtaining test data, scale-up calculations should be made regularly to determnne if the end results will be practical, particularly from the available mixing hardw are, motor pow er, etc. 

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