Flow Principle

The idea of ultrafiltration has been extended ia recent years to the filtration of particles ia the micrometer and submicrometer range ia porous pipes, usiag the same cross-flow principle. In order to prevent blocking, thicker flow channels are necessary, almost exclusively ia the form of tubes. The process is often called cross-flow microfiltration but the term cross-flow filtration is used here. 

FIGURE 4.20 Heat transfer according to the parallel flow principle. 

FIGURE 4.21 Water cooling in a cooling tower, which operates according to the parallel flow principle in other words, the water spray turns in the direction of the air flow. 

From a balanced design, determine the pressure drop for the entire series length of pipe in bank, including fittings. Use copyrighted chart in Reference 36, fluid flow principles, or Figure 10-130 for cast iron sections. 

Shook, C. A. and Roco, M. C. Slurry Flow. Principles and Practice (Butterworth-Heinemann, Oxford, 1991). 

Shook CA, MC Roco. Slurry Flow Principles and Practice. Stoneham, MA Butterworth-Heinemann, 1991. 

Three different principles govern the design of bench-scale calorimetric units heat flow, heat balance, and power consumption. The RC1 [184], for example, is based on the heat-flow principle, by measuring the temperature difference between the reaction mixture and the heat transfer fluid in the reactor jacket. In order to determine the heat release rate, the heat transfer coefficient and area must be known. The Contalab [185], as originally marketed by Contraves, is based on the heat balance principle, by measuring the difference between the temperature of the heat transfer fluid at the jacket inlet and the outlet. Knowledge of the characteristics of the heat transfer fluid, such as mass flow rates and the specific heat, is required. ThermoMetric instruments, such as the CPA [188], are designed on the power compensation principle (i.e., the supply or removal of heat to or from the reactor vessel to maintain reactor contents at a prescribed temperature is measured). 

The waste gas and scrubbing liquid can be put into contact according to the counterflow or cross-flow principle. A counter-flow scrubber, as indicated in Fig. 3, is a... 

Automation has been applied for a number of years in process control instrumentation, but the major impetus to introduce automatic devices into laboratories stems from three sources (1) the introduction of the continuous-flow principles as outlined by Skeggs [1] (2) the general demand for clinical chemical measurements, which represents a ready and sizeable market for instrument companies, and, more importantly, (3) the abihty to handle large volumes of data and package them in a form suitable for presentation to analysts and customers, through the use of mini- and micro computer systems hnked to a control computer. 

This analyser is a computer-controlled automated batch analyser, using a stop-flow principle to analyse for pH, conductivity, turbidity and colour. TTie principle of analysis for each module is based on the recommended methods as detailed in the Examination of Waters and Associated Materials issued by the Standing Committee of Analysts of the Department of the Environment. The temperature of the sample hquid flow is measured in order that temperature-compensated results of pH and conductivity can be quoted. 

There is usually no problem of access to basic laboratory instruments and associated glassware, however, the only means of handling large numbers of tests is to apply some form of automation. An added advantage is that it improves the analytical precision and reproducibility. The most suitable technique has been based on the segmented continuous-flow principle invented by Skeggs (1957), and which was first marketed as the Technicon AutoAnalyzer. The system consists of a number of modules powered from a stabilized 110 V supply, and a typical layout is shown in Fig. 1.1. 

The Matsuzaka Elbow-Jet classifier (Fig. 11) is based on a transverse flow principle (26). The stream of feed particles are accelerated to minimize the effect of gravity, and introduced into an air jet at right angles. The particles are fanned out in the classification zone with the trajectories for particles of the same hydrodynamic behavior, ie, size and shape, being the same. Classification is achieved by mounting one or more cutters in the classification zone, thus dividing the feed into two or more fractions. A stream of fine particles of less than 5 Jm can be produced in this manner. 

Insulation and Heat-Flow Principles. Heat flows from places of higher temperature to those of lower temperature hy one or more of three modes 11) Conductance through solids (2 convection by induced motion of fluids carrying heat and (3) radiation by heal waves emitted from a surface. The rate of heal flow in solids depends upon temperature difference 7j - 7j and the resistances encountered. The heal flow, under steady stale, is expressed by ... 

Flow through a slit head has been studied also in polymers using the power-function flow principle (Ostwald-de Villes model). Some of the first works in this field were carried out in 1967-1968 by N. V. Tyabin et al.21,22). Tests were arranged with molten polyethylene in an extrusion head having a rotary conic core. The divergence between theory and experiment was comparatively significant which, apparently, is accounted for, primarily, by the basence of a necessary similarity between the conducted experiment and the theoretical description of the flow in a flat slit. 

Separation based on rotating flow principles is one of the most common operations involved in gas-solid flows. This section describes the fundamental rotating flow principles and their applications to cyclone operation. The efficiency of dust collection in cyclones is also described. 

Figure 23 Air-breathing microfluidic fuel cells showing the colaminar flow principle, in combination with oxygen capture via gas diffusion through a porous cathode A three-phase interface is established between gas, electrolyte, and catalyst/solid electrode (reprinted with permission from Jayashree et al., 2005. Copyright 2005 American Chemical Society).

After cooling the resin in the reactor, the resin is pumped to the buffer tank of the connected spray dryer plant. Usually, the complete batch processing takes 4-5 h. The urea-formaldehyde resin solution can be dried in a spray dryer based on co-current flow principle. 

The cross-flow principle, where the two fluids are successively brought together in one and the same flow, is applied if one wants to maximize one of two parallel or consecutive reactions [1]. Figure 1 illustrates this type of cross flow for the reaction system... 

The cross-flow principle has also been applied in fluidized-bed reactor technology. In order to minimize the coke formation in continuous decomposition of kerogen to oil and... 

Demonstration of the blood supply to the liver through the portal vein according to the double-flow principle by F. Glenard. 

The project was aimed at the development of an innovative gasifier based on the reverse-flow principle. It should result in an improvement in thermal efficiency, and enabling the conversion of biomass with high ash contents and low ash-melting point. 

Application of the reverse-flow principle will lead to an increase in thermal efficiency. 

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