Pressure drop Water flow calculations

Although excluded-volume effects are well-accepted in polymer chromatography, the preceding arguments are not without controversy in the petroleum literature because of the way that the apparent polymer viscosity in porous media was determined. In our work, we simply report the resistance factor (i.e., the brine mobility before polymer injection divided by the polymer-solution mobility). This is a well-defined parameter that derives directly from the Darcy equation and measurements of pressure drops and flow rates. Advocates of the depletion-layer effects use a different method to determine apparent polymer viscosity in porous media. Specifically, they flush water through the core after polymer injection to determine the permeability reduction or residual resistance factor. The resistance factor during polymer injection is then divided by the residual resistance factor to determine the apparent polymer viscosity in porous media. Unfortunately, several experimental factors can lead to incorrect measurement of high residual resistance factors, which, in turn, lead to calculation of unexpectedly low apparent polymer viscosities in porous media. 

Example 9 Pipe Distrihator A 3-in schedule 40 (inside diameter 7.793 cm) pipe is to be used as a distributor for a flow of 0.010 mVs of water (p = 1,000 kg/m, i= 0.001 Pa s). The pipe is 0.7 m long and is to have 10 holes of uniform diameter and spacing along the length of the pipe. The distributor pipe is submerged. Calculate the required hole size to limit maldistribution to 5 percent, and estimate the pressure drop across the distributor. 

Cascade coolers are a series of standard pipes, usually manifolded in parallel, and connected in series by vertically or horizontally oriented U-bends. Process fluid flows inside the pipe entering at the bottom and water trickles from the top downward over the external pipe surface. The water is collected from a trough under the pipe sections, cooled, and recirculated over the pipe sections. The pipe material can be any of the metallic and also glass, impeiMous graphite, and ceramics. The tubeside coefficient and pressure drop is as in any circular duct. The water coefficient (with Re number less than 2100) is calculated from the following equation by W.H. McAdams, TB. Drew, and G.S. Bays Jr., from the ASME trans. 62, 627-631 (1940). 

Example 13 Packed Column Pressure Drop Air and water are flowing coiinterciirrently through a bed of 2-inch metal Pali rings. The air mass velocity is 2.03 kg/s-m (1500 Ihs/hr-fd), and the liquid mass velocity is 12.20 kg/s-m (9000 Ihs/hr-fr). Calculate the pressure drop hy the generalized pres-... 

For liquids flowing in pipes the pressure drop is commonly taken proportional to a power of the flow rate, usually around 2. One of the simplest correlations used in water distribution network calculation is the Hazen-Williams formula,3... 

You have purchased a centrifugal pump to transport water at a maximum rate of 1000 gpm from one reservoir to another through an 8 in. sch 40 pipeline. The total pressure drop through the pipeline is 50 psi. If the pump has an efficiency of 65% at maximum flow conditions and there is no heat transferred across the pipe wall or the pump casing, calculate ... 

The relationship between flow rate, pressure drop, and pipe diameter for water flowing at 60°F in Schedule 40 horizontal pipe is tabulated in Appendix G over a range of pipe velocities that cover the most likely conditions. For this special case, no iteration or other calculation procedures are required for any of the unknown driving force, unknown flow rate, or unknown diameter problems (although interpolation in the table is usually necessary). Note that the friction loss is tabulated in this table as pressure drop (in psi) per 100 ft of pipe, which is equivalent to 100pef/144L in Bernoulli s equation, where p is in lbm/ft3, ef is in ft lbf/lbm, and L is in ft. 

A column 0.6 m diameter and 4 m high is, packed with 25 mm ceramic Raschig rings and used in a gas absorption process carried out at 101.3 kN/m2 and 293 K. If the liquid and gas properties approximate to those of water and air respectively and their flowrates are 2.5 and 0.6 kg/m2s, what is the pressure drop across the column In making calculations, Carman s method should be used. By how much may the liquid flow rate be increased before the column floods ... 

Pressure driven membrane process, 78 507 Pressure-driven membranes, in water treatment, 26 111 Pressure drop, 77 804 from area change, 73 261-262 in cake filtration, 77 330-332, 333-335 flow maldistribution and, 73 270 from flow turning, 73 262 frictional, 73 260-261 in gas adsorption, 7 657-658 in hyperbar vacuum filtration, 77 377 shellside tube bundle, 73 262-263 in vacuum filtration, 77 349-350 Pressure drop calculations, in heat exchanger design, 73 259-260 Pressure drop information, for resins, 74 399... 

Air and water flow at 8 x 10 3 kg/s and 0.4 kg/s upwards in a vertical, smooth-wall tube of internal diameter dt = 20 mm and length L = 1.3 m. Using the homogeneous flow model, calculate the pressure drop across the tube (neglecting end effects). The fluids are at a temperature of 20 °C and the expansion of the air may be assumed to be isothermal. The exit pressure is 1 bar. 

Empirical equations are also available to calculate the pressure drop for slurries flowing through pipelines [Condolios and Chapus (1963b)]. Durand and Condolios (1955) found the following equation to fit the experimental data for sand-water mixtures flowing above the minimum velocity in horizontal pipes ... 

Nguyen et al. [205] used a technique in which a constant mass flow rate of water-saturated air was forced through a water-saturated sample. It was explained that the shear force of the gas flow dragged water out of the sample. In addition, the saturated air was needed in order to prevent water loss from the sample by evaporation. Once a steady state was achieved, the pressure difference between the inlet and outlet of the apparatus was recorded. After the tests were completed, the sample was weighed to obtain its water content. Thus, the relative permeability was calculated from the pressure drop, the water content in the sample, and the mass flow rate [205]. 

Pressure drop Flow of air through the fluid-bed processor is created by the blower or a fan located downstream from the process chamber. This fan imparts motion and pressure to air using a paddle-wheel action. The moving air acquires a force or pressure component in its direction of motion because of its weight and inertia. This force is called velocity pressure and is measured in inches or millimeters of water column. In operating duct systems, a second pressure that is independent of air velocity or movement is always present. Known as static pressure, it acts equally in all directions. In exhaust systems, such as fluid-bed processors, a negative static pressure exists on the inlet side of the fan. Total pressure is thus a combination of static and velocity pressures. Blower size is determined by calculating... 

A column of water 28 inches high exerts a head pressure of 1 psi, as shown in Fig. 11.3. To determine the pressure drop of water flowing through a hole, in pounds per square inch, we would calculate... 

The correlation of Eckert (Fig. 13.37) combines a pressure drop relation and safe flow rates insofar as staying away from the flooding point is concerned. A flooding line corresponds to pressure drops in excess of 2 in. water/ft. In use, a pressure drop is selected, and the correlation is applied to find the corresponding mass velocity G from which the tower diameter then is calculated. Another correlation recommended by a manufacturer of packings appears in Figure 13.40. Example 13.16 compares these correlations for a specific case they do not compare any more closely than could be expected from the scatter of flooding data. 

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