Pressure tap locations

Fig. 7. Orifice plate pressure tap locations. A, corner taps B, flange taps C, D taps D, 1/2 D taps and E, pena contracta taps. See text.

The experimental equipment is shown in Figure 3.45, where the approximate pressure tap locations are also illustrated. The range of variables studied was as follows (Kopalinsky and Bryant, 1976) ... 

The core - flood apparatus is illustrated in Figure 1. The system consists of two positive displacement pumps with their respective metering controls which are connected through 1/8 inch stainless steel tubing to a cross joint and subsequently to the inlet end of a coreholder 35 cm. long and 4 cm. in diameter. Online filters of 7 im size were used to filter the polymer and brine solutions. A bypass line was used to inject a slug of surfactant solution. Two Validyne pressure transducers with appropriate capacity diaphragms are connected to the system. One of these measured differential pressure between the two pressure taps located about one centimeter from either end of the coreholder, and the other recorded the total pressure drop across the core and was directly connected to the inlet line. A two - channel linear strip chart recorder provided a continuous trace of the pressures. An automatic fraction collector was used to collect the effluent fluids. 

In-situ emulsion formation, as proposed by Kamath et al(19), with DAS surfactants may cause higher pressure drops across the core. This is because of the blocking tendency of the emulsion which has lower mobility. This could explain the earlier plugging of the core compared to other runs. Effluent pH and viscosity showed behavior similar to the previous runs. It is worthwhile noting here that such pressure drops were not manifested by face plugging of the core near the entrance. This was confirmed by simultaneously monitoring the pressure at the inlet end of the core as well as the differential pressure across the two pressure taps located about 1 cm. from each end of the core. The inlet end pressure transducer showed reasonably low pressures throughout the run for each experiment. 

The orifice coefficient shown in Fig. 10-8 is valid to within about 2-5% (depending upon the Reynolds number) for all pressure tap locations except pipe and vena contracta taps. More accurate values can be calculated from Eq. (10-10), with the parameter expressions given in Table 10-1 for the specific orifice and pressure tap arrangement. 

Figure 10-10 Orifice pressure tap locations. (From Miller, 1983.)...

Figure 5-1. Orifice pressure tap locations. 2 1/2D and 8D pipe taps are not recommended in iSO 5167 or ASME fiuid meters. D and D/2 taps are now used in place of...

Figure 5.20 shows the orifice (discharge) coefficient as a function of the orifice Reynolds number ( Rerf) and p = d D. There are a variety of standard orifice plate and pressure tap designs (e.g., Miller, 1983). The ASME specifications for the most common concentric square-edged orifices are shown in Figure 5.21. The various pressure tap locations are illustrated in Figure 5.22. Radius taps, for which the location is scaled to the pipe diameter, are the most reliable. Comer taps and flange taps are the most convenient, as they can be installed in the orifice flange and so do not require...

FIGURE 5.22 Orifice pressure tap locations. (From Miller, R. W., Flow Measurement Engineering Handbook, McGraw-Hill, New York (1983).)... 

The discharge coefficient corrects the theoretical equation for the effects of the approaching velocity profile, the assumption of no energy loss between the pressure taps and pressure tap location and is defined as... 

Fig. 6.14. Plan view of a melter furnace showing suggested furnace pressure tap locations selected to avoid both impulse and suction effects of burner jets or flue.

Example 5.2—Calculation of Polymer Mobility. Data for toe flow of a partially hydrolyzed polyaciylamide through a lO-in.-long Berea sandstone core were obtained by injecting polymer solution at a constant frontal-advance rate and measuring the pressure drop between pressure taps located 8 in. apart. The following data are avallablefiO ky,=516 md, Ap = 1.18 psi, distance between pressure taps is 0.667 ft, frontal-advance rate, v, is 1.85 ft/D, and porosity is 0.21. Determine toe polymer mobility in md/cp from these data. 

Orifice. Equation (M-13) is used for measuring the flow rate of water with orifice and Eq. (M-14) for measuring the rate of flow of air. Interim Supplement 19.5 on Fluid Meters gives the tables of the values of discharge coefficient C for various pipe diameters as a function of diameter ratio P and pipe Reynolds number R, based on orifice diameter d. Excerpts from the tables in the Supplement are given in Table M-7 for the three types of pressure-tap locations. The values below the stepped line are extrapolations and are subject to larger tolerance as given in Table II-V-1 in the Supplement. 

---