Data normalization normalized pressure drop

Figures 14 and 15 show the normalized pressure drop factor for a densely packed bed of monosized spherical particles. For Rem < 7,fv is fairly independent of Rern, and at high Rem values, it increases fairly linearly with Rem. The data points are the experimental results taken from Fand et al. (110), where the bed diameter is D = 86.6 mm and the particle diameter is ds = 3.072 mm. One can observe that the 2-dimen-sional model of Liu et al. (32), referred to as equation 107, agrees with the experimental data fairly well in the whole range of the modified Reynolds number. From Figure 14, one observes a smooth transition from the Darcy s flow to Forchheirner flow regime. The one-dimensional model of Liu et al. (32) (i.e., equation 106) showed only slightly smaller fv value. Hence, the no-slip effect or two-dimensional effect for this bed is small. As shown in Figures 14 and 15, the Ergun equation consistently underpredicts the pressure drop. The deviation becomes larger when flow rate is increased.

Figures 21 and 22 show the normalized pressured drop estimated by equation 128 for a packed D = 5.588 mm, ds = 3.040 mm, and e = 0.5916. The experimental data are taken from Fand and Thinakaran (92). We can observe that the approximate solution, equation 128, predicts fairly well the experimental results and is very good in representing the exact numerical solution of the governing equations. For clarity, Figure 21 is an expanded region for the small Rem values. Even with this scale, we observe that the approximate solution is very close to the exact numerical solution.

It was found that equation 128 is a good prediction for the normalized pressure drop factor when used for data in Figures 14-22. The use... 

Figure 22. Normalized pressure drop factor variation with Re m for a packed bed of monosized spherical particles at high flow rate. The symbols represent the experimental data taken from reference 92.

Figure XXIV-6 schematically shows the PEACER primary system with a nodal scheme for pressure drop calculation. Flow velocity data for the pressure drop calculation have been determined under steady state normal operation. The primary pressure drop distribution is...

Performance Data for Direct-Heat Tray Dryers A standard two-truck diyer is illustrated in Fig. 12-48. Adjustable baffles or a perforated distribution plate is normally employed to develop 0.3 to 1.3 cm of water-pressure drop at the wall through which air enters the truck enclosure. This will enhance the uniformity of air distribution, from top to bottom, among the trays. In three (or more) truck ovens, air-reheat coils may be placed between trucks if the evaporative load is high. Means for reversing air-flow direction may also be provided in multiple-truck units. 

When evaluating a material for the purpose of establishing dense-phase and long-distance suitability, it is important to undertake all the necessary tests (e.g., particle sizing, particle and bulk densities, fluidization and deaeration). Also, if possible, it is useful to compare such results with those obtained on previously conveyed similar materials (e.g., fly ash). However, it should be noted that such an evaluation only is a qualitative one and it is not possible to predict say, minimum air flows or pipeline pressure drop based on such data (i.e., pilot-scale tests normally are required to confirm minimum velocities, friction factors, etc., especially over long distances and for large-diameter pipes). 

For each thickness, at least 10 different flow rate measurements were obtained in order to cover the range of flow rates that a DL experiences during normal fuel cell operation. To obfain fhe corresponding permeabilify, fhe pressure drop resulfs were ploffed as a function of the mass flow rate. After this, the Forchheimer equation was fitted to the plotted data to determine the viscous and inertial permeabilities. As expected, the in-plane permeabilities of each sample DL maferial decreased when the compression pressure was increased. It is also important to mention that these tests were performed in two perpendicular directions for each sample in order to determine whether any anisotropy existed due to fiber orienfation. 

Typical flux data with two interpromoter spacings (AL) are shown in Figure 28 as a function of the cross-flow rate. The flux Increased by a factor of 3 for the best case. Though Probstein did not plot his data in this way, it is Interesting to note that the empty channel flux has a predictable 0.33 power dependence on tangential velocity. With the turbulence promoters, the slope shifts closer to the 0.7-0.8 power dependence normally observed in turbulent flow. Unfortunately, data are not available in Probstein s paper on the increased pressure drop associated with the turbulence promoters, but it would appear that the flux to power ratio is greatly improved with turbulence promoters. 

As mentioned, the aim of the study is to develop desulfurization equipment of industrial interest so understanding its general performance is important. Several sets of typical operation data measured under stable operations are listed in Table 7.5. The comparable data are depending on coal type, S02 content in flue gas ranges from 1400 to 11400 mg/m while the permitted discharge level in China is normally 1200 mg/m3. The data show that the designed equipment exhibits satisfactory global performance and meets the requirements for desulfurization by wet process. Under moderate operation conditions, the content of S02 in the cleaned gas can achieve a much lower level than that permitted. Even if the mole ratio of Ca/S is as low as 1.0, a sulfur-removal efficiency of nearly 90% can be achieved (see the fourth row in Table 7.5) while the pressure drop across the reactor is very small, ca. 400 Pa only. 

Grootenhuis (Proc. Inst. Mech. Eng. [London], A168, 837—846 [1954]) presents data which indicate that for a series of screens, the total pressure drop equals the number of screens times the pressure drop for one screen, and is not affected by the spacing between screens or their orientation with respect to one another, and presents a correlation for frictional losses across plain square-mesh screens and sintered gauzes. Armour and Cannon (AIChE J., 14,415-420 [1968]) give a correlation based on a packed bed model for plain, twill, and dutch weaves. For losses through monofilament fabrics see Pedersen (Filtr. Sep., 11, 586-589 [1975]). For screens Inclined at an angle 0, use the normal velocity component V ... 

H. L. LaNieve IE, and D. C. Bogue, Correlation of Capillary Entrance Pressure Drops with Normal Stress Data, J. Appl. Polym. Sci., 12, 353 (1968). 

Backwashing is necessary to keep the bed in a hydraulically classified condition, to minimize pressure drop, and to remove resin fines and suspended solids that have been filtered out of the influent water. Normal practice is to backwash at the end of each run for about 15 min, so as to obtain about 50 to 75 percent bed expansion. The flow rate required to achieve this expansion is obtained from the manufacturers data. As noted in the statement of the example, an appropriate flow rate in this case is 6.4gal/(min)(ft2). The total backwash rate is thus [6.4gal/(min)(ft2)](14ft2) = 90 gal/min. The total water requirement, then, is (90 gal/min)(15 min) = 1350 gal (5.11 m3). 

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