Direction of flow

The time-to-distance transfonnation requires fast mixing and a known flow profile, ideally a turbulent flow with a well-defined homogeneous composition perpendicular to the direction of flow ( plug-flow ), as indicated by tire shaded area in figure B2.5.1. More complicated profiles may require numerical transfomiations. 

The dynamic viscosity, or coefficient of viscosity, 77 of a Newtonian fluid is defined as the force per unit area necessary to maintain a unit velocity gradient at right angles to the direction of flow between two parallel planes a unit distance apart. The SI unit is pascal-second or newton-second per meter squared [N s m ]. The c.g.s. unit of viscosity is the poise [P] 1 cP = 1 mN s m . The dynamic viscosity decreases with the temperature approximately according to the equation log rj = A + BIT. Values of A and B for a large number of liquids are given by Barrer, Trans. Faraday Soc. 39 48 (1943). 

The saddle-shaped configuration (Fig. 22c) is the most efficient configuration for linear channels. The two saddle shaped cods are located parallel to each other the MHD channel is located in the gap between the two cods. The longitudinal part of the conductors Hes parallel to the direction of flow in the MHD channel, the direction of the field being transverse to the flow in the horizontal plane. This configuration is the most efficient in its use of magnetic... 

The oxygen release rate is directly proportional to the cross-sectional area of the candle for a specific composition and also depends on the linear bum rate. Lower fuel contents decrease the bum rate slightly, eg, ca 2 wt % iron is the lower limit for rehable room temperature operation. Low temperature starts require at least 3.5 wt % iron. Another factor is direction of flow of the evolved gas. If the hot oxygen flows over the unbumed portion of the candle, as much as 15% rate iacreases can be produced. The bum time is halved for each 3.4 MPa (500 psi) pressure rise. The highest pressure that can be produced is ca 138 MPa (20,000 psi). 

Pour typical weU patterns for contaminant plume containment are described in Ref. 16. The first is a pair of injection-production weUs. The second is a line of downgradient pumping weUs. The third is a pattern of injection-production weUs around the boundary of a plume. The fourth, the double-cell system, uses an inner ceU and outer recirculation ceU, with four ceUs along a line bisecting the plume in the direction of flow. Two other methods of plume containment are bio filters and a fuimel-and-gate system, which are described in the in bioremediation section. 

Viscosity is defined as the shear stress per unit area at any point in a confined fluid divided by the velocity gradient in the direc tiou perpendicular to the direction of flow. If this ratio is constant with time at a given temperature and pressure for any species, the fluid is caUed a Newtonian fluid. This section is limited to Newtonian fluids, which include all gases and most uoupolymeric liquids and their mixtures. Most polymers, pastes, slurries, waxy oils, and some silicate esters are examples of uou-Newtouiau fluids. 

The physical properties of spray-dried materials are subject to considerable variation, depending on the direction of flow of the inlet gas and its temperature, the degree and uniformity of atomization, the solids content of the feed, the temperature of the feed, and the degree of aeration of the feed. The properties of the product usually of greatest interest are (1) particle size, (2) bulk density, and (3) dustiness. The particle size is a function of atomizer-operating conditions and also of the solids content, liquid viscosity, liquid density, and feed rate. In general, particle size increases with solids content, viscosity, density, and feed rate. 

Figure 6.25 Low-power scanning electron micrograph of small tubelike organisms in Figs. 6.17 and 6.20. Note how all organisms (except one) point into the direction of flow.

Metal loss of the type illustrated in Fig. 11.14 occurred on the internal surface at the midsection of the tube. Note the erosion grooves oriented in the direction of flow. Metal loss at the inlet end was much more severe and had produced a smooth, relatively featureless contour (Fig. 11.15). Eroded areas were free of corrosion products and deposits. 

Use unique containers (e.g., colors, shapes) where appropriate Identify all process and utility lines (written material name and color coded) Indicate direction of flow, where applicable... 

Transport across tire direction of flow can be determined using Pick s hrst law of diffusion for dre flux of material in particles/cm sec in a steady, time-independent state... 

The temperature gradient in the direction of flow can be measured directly with Pt-resistance thermometers, but it is difficult and expensive. When this is small, it is better to calculate from the material balance and thermochemical properties. 

In a recuperative heat exchanger, each element of heat-transferring surface has a constant temperature and, by arranging the gas paths in contra-flow, the temperature distribution in the matrix in the direction of flow is that giving optimum performance for the given heat-transfer conditions. This optimum temperature distribution can be achieved ideally in a con-tra-flow regenerator and approached very closely in a cross-flow regenerator. 

In Chapter 3 it was pointed out that certain rod-like polymers showed many of the attributes of liquid crystals in the melt. In particular, these molecules were oriented in shear to such an extent that interchain entanglement was small and the melts had a low viscosity. On cooling of the melt these rod-like molecules remained oriented, effectively self-reinforcing the polymer in the direction of flow. The essential differences in the properties of liquid crystal polymers... 

The drying of the curd is completed by passing through a rotary drier such as the Pillet-Bordeaux. In this machine the curd passes down a chute with hot air running counter to the direction of flow of material. Strict temperature control is essential, the maximum discharge temperature being below 65°C. If such control is not made then the resin will be dark in colour. 

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